Federal Motor Vehicle Safety Standards; Minimum Sound Requirements for Hybrid and Electric Vehicles

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA-2016-0125]

RIN 2127-AK93

Federal Motor Vehicle Safety Standards; Minimum Sound Requirements for Hybrid and Electric Vehicles

AGENCY:

National Highway Traffic Safety Administration (NHTSA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

To reduce the risk of pedestrian crashes, especially for the blind and visually-impaired, and to satisfy the mandate in the Pedestrian Safety Enhancement Act (PSEA) of 2010 this final rule establishes a new Federal motor vehicle safety standard (FMVSS) setting minimum sound requirements for hybrid and electric vehicles. This new standard requires hybrid and electric passenger cars, light trucks and vans (LTVs), and low speed vehicles (LSVs) to produce sounds meeting the requirements of this standard. This final rule applies to electric vehicles (EVs) and to those hybrid vehicles (HVs) that are capable of propulsion in any forward or reverse gear without the vehicle's internal combustion engine (ICE) operating. This standard will help to ensure that blind, visually impaired, and other pedestrians are able to detect and recognize nearby hybrid and electric vehicles, as required by the PSEA.

DATES:

Effective date:

This rule is effective February 13, 2017.

Compliance date:

Initial compliance is required, in accordance with the phase-in schedule, on September 1, 2018. Full compliance is required on September 1, 2019.

Petitions for reconsideration:

Petitions for reconsideration of this final rule must be received not later than January 30, 2017.

Incorporation by Reference:

The incorporation by reference of certain publications listed in the standard is approved by the Director of the Federal Register as of February 13, 2017.

ADDRESSES:

Petitions for reconsideration of this final rule must refer to the docket and notice number set forth above and be submitted to the Administrator, National Highway Traffic Safety Administration, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

For non-legal issues, Mr. Mike Pyne, Office of Crash Avoidance Standards (telephone: 202-366-4171) (fax: 202-493-2990). Mr. Pyne's mailing address is National Highway Traffic Safety Administration, NVS-123, 1200 New Jersey Avenue SE., Washington, DC 20590.

For legal issues, Mr. Thomas Healy, Office of the Chief Counsel (telephone: 202-366-2992) (fax: 202-366-3820). Mr. Healy's mailing address is National Highway Traffic Safety Administration, NCC-112, 1200 New Jersey Avenue SE., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary

A. Summary of Requirements of the Final Rule

B. Costs and Benefits

II. Background and Summary of Notice of Proposed Rulemaking

A. Pedestrian Safety Enhancement Act and National Traffic and Motor Vehicle Safety Act

B. Safety Problem

C. Research on Vehicle Emitted Sounds and Detectability

D. Notice of Proposed Rulemaking

E. Summary of Comments to the NPRM

III. Final Rule and Response to Comments

A. Summary of the Final Rule

B. Applicability of the Standard

C. Critical Operating Scenarios

D. Crossover Speed

E. Acoustic Parameters for Detection of Motor Vehicles

F. Acoustic Parameters for Recognition of Motor Vehicles

G. Frequency (Pitch) Shifting and Volume Change

H. Sameness

I. Customer Acceptance

J. Test Conditions

K. Test Procedure

L. Phase-in of Requirements

IV. International Harmonization and Stakeholder Consultation

V. Analysis of Costs, Benefits, and Environmental Effects

A. Benefits

B. Costs

C. Comparison of Costs and Benefits

D. Retrospective Review

E. Environmental Assessment

VI. Regulatory Notices and Analyses

Executive Order (E.O.) 12866 (Regulatory Planning and Review), E.O. 13563, and DOT Regulatory Policies and Procedures

Executive Order 13609: Promoting International Regulatory Cooperation

National Environmental Policy Act

Regulatory Flexibility Act

Executive Order 13132 (Federalism)

Executive Order 12988 (Civil Justice Reform)

Unfunded Mandates Reform Act

Paperwork Reduction Act

Executive Order 13045

National Technology Transfer and Advancement Act

Executive Order 13211

Regulation Identifier Number (RIN)

I. Executive Summary

The PSEA requires NHTSA to establish performance requirements for an alert sound that is recognizable as a motor vehicle in operation that allows blind and other pedestrians to detect nearby electric vehicles or hybrid vehicles operating at lower speeds. This final rule establishes FMVSS No.141,

Minimum Sound Requirements for Hybrid and Electric Vehicles,

which requires hybrid and electric passenger cars and LTVs with a gross vehicle weight rating (GVWR) of 4,536 kg (10,000 lbs.) or less and LSVs, to produce sounds meeting the requirements of this standard so both blind and sighted pedestrians can more easily detect and recognize by hearing these vehicles. Both blind and sighted pedestrians have greater difficulty detecting hybrid and electric vehicles at low speeds than vehicles with ICE engines because hybrid and electric vehicles produce measurably less sound at those speeds.

1

At higher speeds, in contrast, tire and wind noise are the primary contributors to a vehicle's noise output, so the sounds produced by hybrid and electric vehicles and ICE vehicles are similar.

1

Garay-Vega, L; Hastings, A.; Pollard, J.K.; Zuschlag, M. & Stearns, M. (2010, April). Quieter Cars and the Safety of Blind. Pedestrians: Phase 1. DOT HS 811 304. Washington, DC: National Highway Traffic Safety Administration.

Hybrid vehicles with gross vehicle weight rating (GVWR) of 4,536 kg (10,000 lbs.) or less are 1.18 times more likely than an ICE vehicle to be involved in a collision with a pedestrian and 1.51 times more likely to be involved in a collision with a pedalcyclist. NHTSA assumes that this difference in accident rates is mostly attributable to the pedestrians' inability to detect the presence of these vehicles through hearing.

To further evaluate the assumption that the difference in crash rates is mostly attributable to differences in vehicle emitted sound, the agency conducted research to see if there was a difference in the ability of pedestrians to detect approaching hybrid and electric vehicles versus ICE vehicles. The agency also conducted research to examine how the frequency composition of a sound influenced the ability of pedestrians to detect that sound in the presence of ambient noise. Section II.C provides much more information on this research and how the agency used it in the context of this rulemaking.

A. Summary of Requirements of the Final Rule

On January 14, 2013, NHTSA published a notice of proposed rulemaking (NPRM) specifying minimum sound requirements for hybrid and electric vehicles.

2

The NPRM discussed three alternative means for the agency to establish requirements for, and measure compliance with, minimum levels of vehicle emitted sound. In the NPRM, the agency proposed its preferred alternative which was to establish minimum requirements for vehicle emitted sound using a psychoacoustic model. Sounds meeting the proposed requirements would contain acoustic elements designed to enhance detection and to aid pedestrians in recognizing the sound as coming from a motor vehicle. We believed that the preferred alternative placed the greatest emphasis on ensuring the vehicle emitted sounds were detectable to pedestrians. In addition to the preferred alternative, the NPRM also discussed minimum sound requirements for HVs and EVs designed to resemble sounds produced by ICE vehicles. This alternative would place a greater emphasis on recognizability than the preferred alternative. Compliance with both of these alternatives would be determined using a compliance test that measured the sound produced by the vehicle.

2

78 FR 2797.

In order to provide an alternative that would allow the most flexibility in the types of sounds that manufacturers could choose to add to vehicles to alert pedestrians, we also discussed using human factors testing to determine whether a sound used to alert pedestrians was recognizable as a motor vehicle.

After careful consideration of all available information, including the public comments submitted in response to the NPRM,

3

the agency has decided to adopt the preferred alternative in the NPRM and many of the elements of the proposed rule. In the final rule, as proposed, the agency requires hybrid and electric vehicles to emit sound while the vehicle is stationary with the vehicle propulsion system activated. (However, in the final rule this requirement does not apply to vehicles that are parked with the propulsion system activated—see below.) Also as proposed, the agency requires hybrid and electric vehicles to emit minimum sound levels while in reverse and while the vehicle is in forward motion up to 30 km/h. The final rule also adopts the agency's proposal to conduct compliance testing outdoors.

3

“Federal Motor Vehicle Safety Standards; Minimum Sound Requirements for Hybrid and Electric Vehicles,” 78 FR 2798 (January 14, 2013).

With regard to the scope of the final rule and what level of sound to emit and when, however, the agency is adopting numerous changes to the proposal in response to additional analysis conducted by the agency and in response to comments, including the following:

• The final rule will only apply to four-wheeled hybrid and electric vehicles with a gross vehicle weight rating (GVWR) of 4,536 kg (10,000) pounds or less. The NPRM proposed that this rule would also apply to hybrid and electric vehicles with a GVWR over 4,536 kg (10,000) pounds and to electric motorcycles. We believe that we do not have enough information at this time to apply the minimum acoustic requirements of this final rule to these vehicles.

• In this final rule, the agency is reducing the number of one-third octave bands for which there are minimum requirements. The NPRM proposed that vehicles would have to emit sound meeting minimum requirements in eight one-third octave bands. To comply with this final rule, hybrid and electric vehicles will instead have to meet a requirement specifying either two or four one-third octave bands. Vehicles complying with the four-band requirement must meet minimum sound pressure levels in any four non-adjacent one-third octave bands between 315 Hz and 5000 Hz, including the one-third octave bands between 630 Hz and 1600 Hz (these bands were excluded in the NPRM). Vehicles complying with the two-band requirement must meet minimum sound pressure levels in two non-adjacent one-third octave bands between 315 Hz and 3150 Hz. For the two-band requirement, one band must be below 1000 Hz and the second band must be at or above 1000 Hz, and the two bands used to meet the two-band requirement also must meet a minimum band sum requirement.

• The NPRM proposed that the fundamental frequency of the sound emitted by a hybrid or electric vehicle must vary as the vehicle changes speed by one percent per km/h for speeds between 0 and 30 km/h to allow pedestrians to detect vehicle acceleration and deceleration. This requirement was referred to as “pitch shifting,” and it is not required in the final rule. Instead, the final rule assists pedestrians in detecting increases in vehicle speed by requiring vehicle-emitted sound to increase in sound pressure level by a specified amount as the vehicle's speed increases. The agency acknowledges that the concept of increasing sound pressure level with increased speed is not a direct replacement for pitch shifting, but we believe it is a reasonable alternative that will provide useful audible information to pedestrians about the operating state of nearby vehicles.

• The NPRM proposed that sound emitted by hybrid and electric vehicles must contain one tone no higher than 400 Hz and emit broadband content including each one-third octave band from 160 Hz to 5000 Hz so that sounds emitted by these vehicles would be recognizable as motor vehicles. The final rule does not adopt these proposed requirements. We believe that pedestrians will use other cues to recognize EVs and HVs such as the location of the sound source and the frequency and level changes caused by the motion of the sound.

• In order to ensure that hybrid and electric vehicles of the same make, model, and model year emit the same sound, as required by the PSEA, the NPRM proposed that vehicles of the same make, model, and model year must emit the same level of sound, within 3 dB(A), in each one-third octave band from 160 Hz to 5000 Hz. We have instead decided to ensure that EVs and HVs of the same make, model, and model year emit the same sound by requiring that all vehicles of the same make, model, and model year use the same alert system hardware and software, including specific items such as the same digital sound file where applicable, to produce sound used to meet the minimum sound requirements in today's final rule.

• The NPRM proposed that each hybrid and electric vehicle must meet minimum sound requirements anytime the vehicle's propulsion system is activated, including when the vehicle is stationary. The final rule requires each hybrid and electric vehicle to meet minimum sound requirements any time the vehicle's propulsion system is activated, including when the vehicle is stationary, unless the vehicle's gear selector is in the “park” position or the parking brake is applied (the latter for HVs and EVs with manual transmissions).

• The NPRM proposed a phase-in schedule that required each manufacturer of hybrid and electric vehicles to begin meeting the requirements of the final rule with 30 percent of the hybrid and electric vehicles they produce three years before the date for full compliance established in the PSEA. In the final rule, we have modified the phase-in schedule to provide additional time for compliance

for manufacturers of light vehicles; 50 percent of each manufacturer's HV and EV production must comply with this final rule one year before the date for full compliance established in the PSEA of September 1, 2019.

B. Costs and Benefits

As discussed in detail in Section V of this notice, the benefits of this final rule will accrue from injuries to pedestrians that will be avoided, based on the anticipated ability of this rule to reduce the pedestrian injury rate for HVs and EVs to that of ICE vehicles. As discussed in Section II.B, a traditional analysis of pedestrian fatalities is not appropriate for this rulemaking. If we assume that HVs and EVs increase their presence in the U.S. fleet to four percent of all vehicle registrations in model year 2020, a total of 2,464 injuries to pedestrians and pedalcyclists would be expected over the lifetime of the 2020 model year fleet due to the pedestrians' and pedalcyclists' inability to detect these vehicles by their sense of hearing. Taking into account the agency's estimate of detectability of vehicle alert sounds complying with this final rule, which is discussed in the Final Regulatory Impact Assessment, we estimate that the benefit of reducing the pedestrian and pedalcyclist injury rate per registered vehicle for EVs HVs to ICE vehicles when four percent of the fleet is HVs and EVs would be 2,390 fewer injured pedestrians and pedalcyclists. We do not include any quantifiable benefits in pedestrian or pedalcyclist injury reduction for EVs because we believe it is reasonable to assume that EV manufacturers would have installed alert sounds in their cars without passage of the PSEA and this proposed rule.

4

We also estimate that this rule will result in 11 fewer injured pedestrians and pedalcyclists caused by LSVs.

4

As further discussed in the agency's Final Regulatory Impact Analysis, due to foresight on the part of light electric vehicle manufacturers, paired with consumer expectations and style choices, light vehicle EVs are all assumed to be equipped with speaker systems. NHTSA assumes the sound alert benefits for these vehicles are attributable to the market and not the rule. This assumption makes our benefit figures conservative. On the other hand, we did not assume that electric LSVs would be voluntarily equipped with speaker systems since none of these vehicles were known to have such systems currently.

5

Scaled benefits and costs for low-speed vehicles (LSVs) are estimated to be directly proportional to costs for light vehicles based on sales. Scaled costs include both installation costs for the system and fuel costs.

Table 1—Discounted Benefits for Passenger Cars and LTVs, MY2020, 2013$

3%

Discount

Pedestrians

3%

Discount

factor

Total

monetized

benefits

Total ELS

Pedalcyclists

3%

Discount

factor

Total

monetized

benefits

Total ELS

Total PED + CYC

3%

Discount

factor

Total

monetized

benefits

Total ELS

(PC)

0.8024

$132.3M

9.70

0.80243

$168.8M

14.55

0.8024

$301.1M

24.25

(LTV)

0.7867

7.9M

0.58

0.78673

9.4M

0.80

0.7867

17.4M

1.39

Total

0

140.3M

10.29

0

178.3M

15.35

0

318.5M

25.64

7% Discount

7%

Discount

factor

Total

monetized

benefits

Total ELS

7%

Discount

factor

Total

monetized

benefits

Total ELS

7%

Discount

factor

Total

monetized

benefits

Total ELS

(PC)

0.6268

$102.5M

7.50

0.62684

$130.5M

11.24

0.6268

$233.0M

18.74

(LTV)

0.6077

6.1M

0.45

0.60775

7.2M

0.61

0.6077

13.3M

1.06

Total

0

108.6M

7.94

0

137.7M

11.85

0

246.3M

19.80

Table 2—Total Costs for PCs and LTVs, MY2020, 2013$

Sales

Sales

impacted

Fuel

costs/veh

Fuel costs

(total)

Avg.

install

costs/veh

Install

costs

total

Total

cost/veh

Total costs

3% discount:

(PC)

8,000,000

483,462

$4.70

$2,272,270

$74.36

$35,951,512

$79.06

$38,223,782

(LTV)

8,000,000

46,428

5.30

246,067

71.97

3,341,333

77.27

3,587,400

Total

16,000,000

529,889

$4.75

$2,518,337

$74.15

$39,292,845

$78.91

$41,811,182

7% discount:

(PC)

8,000,000

483,462

$3.80

$1,837,155

$74.36

$35,951,512

$78.16

$37,788,667

(LTV)

8,000,000

46,428

4.20

194,996

71.97

3,341,333

76.17

3,536,329

Total

16,000,000

529,889

3.84

2,032,151

74.15

39,292,845

77.99

41,324,996

Table 3—Costs and Scaled Benefits for LSVs, MY2020

5

Discount

rate

(%)

Sales ratio

LSV to light

vehicle

(%)

Sales

Scaled costs

Scaled

injuries

(undisc.)

Scaled ELS

Scaled

benefits

Scaled

benefits minus scaled

costs

3

0.47

2,500

$197,264

11.28

0.1210

$1,502,807

$1,305,543

7

0.47

2,500

194,970

11.28

0.0934

1,161,989

967,019

NHTSA estimates that the fuel and installation cost of adding a speaker system in order to comply with the requirements of this rule is $129.84 per vehicle for unequipped hybrid light vehicles (

i.e.,

vehicles that did not previously have any alert system components installed), and $54.99 for electric light vehicles. We estimate that for model year (MY) 2020, which is the first model year to which the requirements of this final rule will apply to the entire light vehicle fleet, this final rule will apply to 529,889 passenger cars and LTVs. The estimated costs for manufacturers of complying with this rule is $39.29M in MY 2020, and we would expect that due to the additional weight that these components add to the vehicles in which they are installed, if manufacturers make no other changes to reduce vehicle weight, these vehicles would consume an additional 2.3 more gallons of fuel over the lifetime of a passenger car and 2.5 more gallons of fuel over the lifetime of a light truck which would result in an average fuel cost of $4.75 per vehicle for over the lifetime of MY 2020 vehicles subject to the rule at the 3-percent discount rate and $3.84 per vehicle for over the lifetime of MY 2020 vehicles subject to the rule at the 7-percent discount rate.).

To more easily compare the costs and benefits of this rulemaking, we have converted pedestrian and pedalcyclist injuries avoided into equivalent lives saved. We estimate that the impact of this rule in pedestrian and pedalcyclist injury reduction in light vehicles and LSVs will be 25.76 equivalent lives saved at the 3-percent discount rate and 19.92 equivalent lives saved at the 7-percent discount rate (summing values from Table 1 and Table 3). Converting that to dollars, the benefits of this rule for the HV portion of the MY 2020 light vehicle and LSV fleet are $320.0 million at the 3-percent discount rate and $247.5 million at the 7-percent discount rate (Table 4).

6

NHTSA estimates that the cost per equivalent life saved for the light EV, HV, and LSV fleet would range from a cost of $1.67 million to a cost savings of $0.10 million across the 3-percent and 7-percent discount levels, respectively. When compared to our comprehensive cost estimate of the value of a statistical life of $9.2 million, this final rule is cost effective.

6

NHTSA's benefits calculation does not include light EVs because manufacturers of light EVs were already adding sound to those vehicles prior to NHTSA issuing the NPRM. However, this analysis includes LSVs because those vehicles currently do not have added sound.

Table 4—Total Benefits and Costs Summary for Light Vehicles and Low Speed Vehicles, MY2020, 2013$

3% Discount

rate

7% Discount

rate

Total Monetized Benefits

$320.0M

$247.5M

Total Costs (Install + Fuel)

42.M

41.5M

Total Net Impact (Benefit−Costs)

278.0M

205.9

II. Background and Summary of Notice of Proposed Rulemaking

A. Pedestrian Safety Enhancement Act and National Traffic and Motor Vehicle Safety Act

On January 4, 2011, the Pedestrian Safety Enhancement Act of 2010 (Pub. L. 111-373) was signed into law. The Pedestrian Safety Enhancement Act (PSEA) requires NHTSA to conduct a rulemaking to establish a Federal Motor Vehicle Safety Standard (FMVSS)

7

requiring an “alert sound”

8

for pedestrians to be emitted by all types of motor vehicles

9

that are electric vehicles

10

(EVs) or hybrid vehicles

11

(HVs). Trailers are specifically excluded from the requirements of the PSEA.

7

NHTSA is delegated authority by the Secretary of Transportation to carry out Chapter 301 of Title 49 of the United States Code.

See

49 CFR 501.2. This includes the authority to issue Federal motor vehicle safety standards.

See

49 U.S.C. 30111.

8

The definition of the term “alert sound” is discussed below.

9

Section 2(4) of the PSEA defines the term “motor vehicle” as having the meaning given such term in section 30102(a)(6) of title 49, United States Code, except that such term shall not include a trailer (as such term is defined in section 571.3 of title 49, Code of Federal Regulations). Section 30102(a)(6) defines “motor vehicle” as meaning a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line.

10

Section 2(10) of the PSEA defines “electric vehicle” as a motor vehicle with an electric motor as its sole means of propulsion.

11

Section 2(9) of the PSEA defines “hybrid vehicle” as a motor vehicle which has more than one means of propulsion. As a practical matter, this term is currently essentially synonymous with “hybrid electric vehicle.”

The PSEA requires NHTSA to establish performance requirements for an alert sound that allows blind and other pedestrians to reasonably detect a nearby EV or HV. The PSEA defines “alert sound,” as that term is used in the statute, as a vehicle-emitted sound that enables pedestrians to discern the presence, direction,

12

location, and operation of the vehicle.

13

Thus, in order for a vehicle to satisfy the requirement in the PSEA to provide an “alert sound,” the sound emitted by the vehicle must satisfy that definition. The alert sound must not require activation by the driver or the pedestrian, and must allow pedestrians to reasonably detect an EV or HV in critical operating scenarios such as constant speed, accelerating, or decelerating.

12

The PSEA does not specify whether vehicle “direction” is to be defined with reference to the vehicle itself (thus meaning forward or backward) or the pedestrian.

13

PSEA Section 2(2).

In addition to those operating scenarios, the definition of alert sound in the PSEA requires the agency to establish requirements for a sound while the vehicle is stationary but active and when the vehicle is operating in reverse. PSEA states that the alert sound must allow pedestrians to “discern vehicle presence, direction, location, and operation.”

14

We read the requirement that pedestrians be able to “discern vehicle presence” along with the requirements that the sound allow pedestrians to discern direction, location, and operation. The term “presence” means something that is in the immediate vicinity. The term “operation” means a state of being functional or operative. Read together, the definition of alert sound requires that pedestrians be able to detect vehicle presence when the vehicle is in operation. A vehicle with its gear selector not in “park” is in an operational state even though it may not be moving. It is therefore the agency's position that the provision of the PSEA that requires pedestrians to be able to detect the presence of a vehicle in operation requires that the vehicle emit a minimum sound level when its gear selector is in any position other than “park,” whether that be when the vehicle is moving forward, stationary, or operating in reverse.

14

Public Law 111-373, 2(2), 124 Stat. 4086 (2011).

The agency believes that it is reasonable to conclude that Congress intended the term “operation” in the PSEA to be the condition in which a driver is operating the vehicle, as opposed to just the operation of the vehicle's propulsion system. It is the operation of the vehicle by a driver, not the operation of the vehicle's propulsion system, that creates the safety risk to pedestrians who fail to detect hybrid and electric vehicles. Consequently, when the vehicle's gear selector is in “park,” the propulsion system may or may not be activated but, in such a condition when the propulsion system is activated, the vehicle is not operable by the driver until the gear selector is moved from “park” to some other gear selector position. Therefore, we have determined that the PSEA does not require us to establish minimum sound requirements for when a vehicle has its gear selector control in the “park” position.

Because the PSEA directs NHTSA to issue these requirements as an FMVSS under the National Traffic and Motor Vehicle Safety Act (Vehicle Safety Act),

15

the requirements must comply with that Act as well as the PSEA. The Vehicle Safety Act requires each safety standard to be performance-oriented, practicable

16

and objective

17

and meet the need for safety. In addition, in developing and issuing a standard, NHTSA must consider whether the standard is reasonable, practicable, and appropriate for each type of motor vehicle covered by the standard.

15

49 U.S.C. Chapter 301.

16

In a case involving passive occupant restraints, the U.S. Circuit Court of Appeals for the District of Columbia said that the agency must consider public reaction in assessing the practicability of required safety equipment like an ignition interlock for seat belts. Pacific Legal Foundation v. Department of Transportation, 593 F.2d 1338 (D.C. Cir. 1978). cert. denied, 444 U.S. 830 (1979).

17

In a case involving passive occupant restraints, the U.S. Circuit Court of Appeals for the 6th Circuit said, quoting the House Report (H.R. 1776, 89th Cong. 2d Sess. 1966, p. 16) for the original Vehicle Safety Act, that “objective criteria are absolutely necessary so that `the question of whether there is compliance with the standard can be answered by objective measurement and without recourse to any subjective determination.' ”

Chrysler

v.

Department of Transportation,

472 F.2d 659 (6th Cir. 1972).

As an FMVSS, the minimum sound standard in today's final rule will be enforced in the same fashion as other safety standards issued under the Vehicle Safety Act. Thus, violators of the standard will be subject to civil penalties.

18

Vehicle manufacturers will be required to conduct a recall and provide remedy without charge if their vehicles are determined to fail to comply with the standard or if the vehicle's alert sound were determined to contain a safety related defect.

19

18

49 U.S.C. 30112 and 30165.

19

49 U.S.C. 30118-30120.

Under the PSEA, the standard must specify performance requirements for an alert sound that enables blind and other pedestrians to reasonably detect EVs and HVs operating below their crossover speed.

20

The PSEA specifies several requirements regarding the performance of the alert sound to enable pedestrians to discern the operation of vehicles subject to the Act. First, the alert sound must be sufficient to allow a pedestrian to reasonably detect a nearby EV or HV operating at constant speed, accelerating, decelerating or operating in any other scenarios that the Secretary deems appropriate.

21

Second, it must reflect the agency's determination of the minimum sound level emitted by a motor vehicle that is necessary to allow blind and other pedestrians to reasonably detect a nearby EV or HV operating at or below the crossover speed.

22

Today's final rule will ensure that EVs and HVs are detectable to pedestrians by specifying performance requirements for sound emitted by these vehicles so that they will be audible to pedestrians across a range of ambient noise environments, including those typical of urban areas.

20

Section 2(3) of the PSEA defines “crossover speed” as the speed at which tire noise, wind resistance, or other factors make an EV or HV detectable by pedestrians without the aid of an alert sound. The definition requires NHTSA to determine the speed at which an alert sound is no longer necessary.

21

PSEA Section 3(a). Under the PSEA, as with most legislation like it, the Secretary of Transportation delegates responsibility for achieving the legislation's objectives to the appropriate Department of Transportation Administration, in this case NHTSA.

22

PSEA Section 3(b).

Nothing in the PSEA specifically requires the alert sound to be electrically generated. Therefore, if manufacturers wish to meet the minimum sound level requirements specified by the agency through the use of sound generated by the vehicle's power train or any other vehicle component, there are no conflicts with the PSEA to limit their flexibility to do so.

The alert sound must also reflect the agency's determination of the performance requirements necessary to ensure that each vehicle's alert sound is recognizable to pedestrians as that of a motor vehicle in operation.

23

We note that the requirement that the alert sound be recognizable as a motor vehicle in operation does not mean that the alert sound be recognizable as a vehicle with an internal combustion engine (ICE). The PSEA defines “conventional motor vehicle” as “a motor vehicle powered by a gasoline, diesel, or alternative fueled internal combustion engine as its sole means of propulsion.”

24

We believe that if Congress had intended the alert sound required by the PSEA to be recognizable as an ICE vehicle, Congress would have specified that the sound must be recognizable as a “conventional motor vehicle” in operation rather than a motor vehicle because Congress acts purposefully in its choice of particular language in a statute.

25

23

PSEA Section 3(b)(2).

24

PSEA Section 2(5).

25

See Keene Corp.

v.

United States,

508 U.S. 200, 208 (1993) (stating the cannon of statutory construction that “where Congress includes particular language in one section of a statute but omits it in another . . ., it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion.”).

While the mandate that NHTSA develop performance requirements for an alert sound that is recognizable as a motor vehicle does not mean that the sound must be based solely on sounds produced by ICE vehicles, the mandate does impose substantive requirements that the agency must follow during the rulemaking. The Vehicle Safety Act defines a motor vehicle as a “vehicle driven or drawn by mechanical power and manufactured primarily for use” on public roads.

26

The requirement that the agency develop performance requirements for recognizability means that the pedestrian alert sound required by this standard must include acoustic characteristics common to all sounds produced by vehicles driven by mechanical power that make those sounds recognizable as a motor vehicle based on the public's experience and expectations of those sounds.

26

49 U.S.C. 30102(a)(6).

The PSEA mandates that the standard shall not require the alert sound to be dependent on either driver or pedestrian activation. It also requires that the safety standard allow manufacturers to provide each vehicle with one or more alert sounds that comply, at the time of manufacture, with the safety standard. Thus, a manufacturer may, if it so chooses, equip a vehicle with different sounds to denote different operating scenarios, such as stationary, forward or reverse. Each vehicle of the same make and model must emit the same alert sound or set of sounds. The standard is required to prohibit manufacturers from providing anyone, other than the manufacturer or dealers, with a device designed to disable, alter, replace or modify the alert sound or set of sounds emitted from the vehicle. This language prohibits NHTSA from allowing

manufacturers from installing an off switch or volume control switch that allows the driver to turn off or turn down the alert sound used to meet the requirements of this standard.

Additionally, vehicle manufacturers, distributors, dealers, and motor vehicle repair businesses would be prohibited from rendering the sound system inoperative under Section 30122 of the Vehicle Safety Act. A manufacturer or a dealer, however, is allowed to alter, replace, or modify the alert sound or set of sounds in order to remedy a defect or non-compliance with the safety standard.

It is the agency's intention that the requirements of this standard be technology neutral. For this reason, we have chosen to establish minimum sound requirements for a vehicle-level test, as opposed to a component-based bench test or some other type of test, to ensure any kind of technology used can be properly tested.

The agency interprets the requirement in the PSEA that each vehicle of the same make and model emit the same sound as applying only to sound added to a vehicle for the purposes of complying with this standard. We also interpret the PSEA requirement that NHTSA prohibit manufacturers from providing anyone with a means of modifying or disabling the alert sound and the prohibition on making required safety systems inoperative contained in Section 30122 of the Vehicle Safety Act as applying only to sound added to a vehicle for the purposes of complying with this proposed standard.

Many changes to a vehicle could affect the sound produced by that vehicle. In issuing this proposal the agency does not wish to prevent manufacturers, dealers, and repair businesses from making modifications to a vehicle such as adding a spoiler or changing the vehicle's tires that may have the effect of changing the sound produced by the vehicle.

The PSEA requires that the final rule provide a phase-in period, as determined by the agency. In response to that requirement, full compliance with the standard must be achieved for all vehicles manufactured on or after September 1st of the calendar year beginning three years after the date of publication of the final rule. This final rule is establishing the requirement for 100-percent compliance for all light vehicles subject to the requirements of this rule produced for sale in the U.S. by all manufacturers no later than September 1, 2019. This requirement includes a one-year, 50-percent phase-in period beginning September 1, 2018.

B. Safety Problem

Comparing the Vehicle-to-Pedestrian Crash Experience of ICE Vehicles to HVs and EVs

Crash Risk

Public safety advocacy groups have raised pedestrian safety concerns regarding HVs because a vehicle using an electric motor may be quieter than an ICE vehicle and may not emit the sounds that non-motorists rely on for warning as vehicles approach them.

In 2009, NHTSA released the report “Incidence of Pedestrian and Bicyclist Crashes by Hybrid Electric Passenger Vehicles” which found that, when comparing similar vehicles, 77 out of 8,387 total HVs reported to be in any crash incident were involved in pedestrian crashes, and 3,578 out of 559,703 total ICE vehicles were involved in similar pedestrian crashes.

27

The report used data collected from 12 individual states. The years for which data were available varied across different states. Generally, the data used ranged from the years 2000 to 2006. The ratio of pedestrian crashes to overall crashes was 40-percent higher for HVs than for other vehicles. In situations involving certain low-speed maneuvers, HVs were twice as likely to be involved in a pedestrian crash as ICE vehicles in similar situations.

27

R. Hanna (2009) Incidence of Pedestrian and Bicyclists Crashes by Hybrid Electric Passenger Vehicles, Report No. DOT HS 811 204. U.S. Dept. of Transportation, Washington, DC.

Available at

http://www-nrd.nhtsa.dot.gov/Pubs/811204.PDf

.

In 2011 NHTSA released a second report “Incidence Rates of Pedestrian And Bicyclist Crashes by Hybrid Electric Passenger Vehicles: An Update” which verified these previous findings

28

by adding additional years of state crash files as well as by increasing the number of states included in the analysis from 12 to 16, which increased the number of crashes included in the analysis. Overall, a statistical approach referred to as odds ratios indicated that the odds of an HV being in either a pedestrian or bicycle crash is greater than the odds of an ICE vehicle being in a similar crash, 19-percent higher for pedestrian crash odds and 38-percent higher for bicycle crash odds.

29

The crash factors of speed limit, vehicle maneuver, and location were examined to determine the relative incidence rates of HVs versus ICE vehicles and whether the odds ratio was different under different circumstances. The analysis also indicated that the largest differences between the involvement of HVs and ICE vehicles in pedestrian crashes occur with speed limits of 35 mph and lower and during certain maneuvers typically executed at low speed such as making a turn, starting up, and pulling into or backing out of a parking space. HVs were about 1.38 times more likely to be involved in a pedestrian crash than a vehicle with an ICE during a low speed maneuver. The results of the updated analysis show trends similar to those first reported in our 2009 analysis. The sample sizes of pedestrian and bicycle crashes were re-examined to verify that there was sufficient statistical power in this updated analysis.

28

Wu, et al. (2011) Incidence Rates of Pedestrian And Bicyclist Crashes by Hybrid Electric Passenger Vehicles: An Update, Report No. DOT HS 811 526. Dept. of Transportation, Washington, DC. Available at

http://www-nrd.nhtsa.dot.gov/Pubs/811526.pdf

.

29

The incidence rates for pedestrian and pedalcyclist crashes involving HVs and EVs were calculated from the State data by comparing the pedestrian and pedalcyclist crash rates for all HVs contained in the State data set with the crash rates for all ICE vehicles from that data set. Because this proposal does not apply to HVs that always have their ICE turned on while moving, the agency removed the Honda Civic and the Honda Accord from the HV category and included those vehicles in the calculations as ICE vehicles in estimating the incidence rate used in the benefit calculations.

The state data set that NHTSA used to determine the pedestrian and pedalcyclist crash rates for HVs did not include any information about the vision status of the pedestrians involved in the crashes, so we were unable to determine whether any of the pedestrians involved in these crashes were blind or visually-impaired.

While this updated analysis provides insightful comparisons of the incidence rates of HVs versus ICE vehicles involved in pedestrian crashes, there are some limitations to consider: The use of data from 16 states cannot be used to directly estimate the national problem size; and there is still not enough data to draw conclusions in all scenarios of interest such as for individual low-speed maneuvers such as making a turn, starting up, or in parking lots.

It has been an ongoing concern that HVs have a very small share among all vehicles (approximately 0.5 percent). The conditional probability of HV pedestrian or pedalcyclist crashes is very small if whole populations of both HV and ICE are included. Therefore, the sample size of HV may have an impact on the comparison of crash rates between HVs and ICE vehicles. For this reason, NHTSA has further updated the comparison between HV and ICE crash data in order to include additional HV crashes.

In our recent calculations

30

we used the latest State data available up to 2011 from the same 16 states, in which the sample sizes of HV vehicles of all crashes are increased to 68,950 (with 420 pedestrian crashes for all hybrid vehicle models). The earlier research obtained the pedestrian crash odds ratios of HV versus ICE vehicle with much smaller sample sizes. The new analysis showed that after the Honda Civic and Accord models are moved from the hybrid category to the ICE category the odds ratio of HV vs. ICE pedestrian crashes for all speeds is 1.21 and the odds ratio for slower speed maneuvers is 1.52. This analysis also shows that the odds ratio of HV vs. ICE pedalcyclist crashes is 1.58 for all speeds including all speed maneuvers, and 1.50 for slower maneuvers.

30

Wu, J., 2015, “Updated Analysis of Pedestrian and Pedalcyclist Crashes of Hybrid Vehicles with Larger Samples and Multiple Risk Factors.”

In the NPRM, the agency asked for comments on whether the differences in pedestrian crash rates between HV and ICE vehicles are solely due to pedestrians' inability to detect these vehicles based on sound, or whether there may be other factors that we have not identified that affect the difference in crash rates.

Ideally, in order to determine whether this lack of sound is causing accidents, NHTSA would have compared accident rates for HVs and EVs with and without sound. However, there have not been enough HVs and EVs with sound for a long enough period of data to be able reasonably conduct this analysis. NHTSA has also been unable to directly measure the pedestrian and pedalcyclist crash rates per mile travelled for HVs and EVs to the rates for ICEs because the Agency does not have data on VMT for HVs and EVs. Therefore, we have instead used the number of other types of crashes vehicles are involved in and using that as a proxy for VMT. While this is a standard technique in analyzing crash risk, it does raise the possibility that there may be other explanations than the lack of sound for hybrids having higher-than-average rates of pedestrian and pedalcyclist crashes relative to other crashes.

Various comments noted that the agency should consider the possibility that factors other than sound will have an impact on the difference in crash rates between HVs and ICE vehicles. Commenters stated that driver characteristics and higher rates of exposure to pedestrians were factors that could contribute to the higher rate of pedestrian crashes among HVs when compared to ICE vehicles.

Nissan North America, Inc. (Nissan) stated that NHTSA should take into account the fact that the “making a turn” and “backing” maneuvers, which constitute a majority of the low speed maneuvers examined in the agency's crash analysis, are maneuvers during which it is difficult for drivers to detect pedestrians. American Honda Motor Co. (Honda) stated that NHTSA should examine whether there is a significant difference between HEV/EV pedestrian crashes and ICE pedestrian crashes for vehicles starting from stationary.

Advocates stated that elevated crash rates between EVs/HEVs and pedestrians and pedalcyclists, concerns of blind advocacy groups, and the international attention focused on the issue support the conclusion that minimum sound requirements for EVs and HEVs will reduce the rate of pedestrian crashes involving these vehicles. The Insurance Institute for Highway Safety stated that, according to research from the Highway Data Loss Institute (HDLI), hybrid vehicles where 17.2 percent more likely to cause injuries to pedestrians than their ICE vehicle counterparts.

Agency Response to Comments

After review of the comments received on the NPRM, we utilized a multivariate logistic regression model to examine whether other variables besides type of powertrain in the State Data System contributed to increased risk of pedestrian collisions. In addition, we utilized the calculated odds ratio to compare HVs and ICEs using a case-control analysis. The variables that NHTSA examined in the regression are: Whether the vehicle was an HV or ICE; whether the vehicle was involved in a low-speed maneuver at the time of the crash; city size; driver age; vehicle age; and calendar year. The results of the regression analysis show that an HV may have 1.18 times higher likelihood of hitting a pedestrian than an ICE after accounting for these other confounding risk factors included in the State Data System. NHTSA believes that our case-control analysis, the results of our multivariate logistic regression, and the results of HDLI's research show that there is a difference in crash rates between HVs and ICE vehicles that is attributable to sound. We note that we were unable to calculate a statistically significant difference in crash rates between HVs and ICE vehicles for pedestrian crashes when the vehicle was starting from a stopped position because of the small number of crashes involving HVs in the State Data System.

We have considered the fact that many of the crashes in the low-speed maneuver data in our crash analysis include crashes in which the driver was making a turn or backing and may have had an obstructed view of the pedestrian. Because backing crashes are addressed by our recent final rule to increase the field of view requirements of FMVSS No. 111,

Rear Visibility,

we have adjusted our benefits calculation for this rulemaking to remove those crashes addressed by FMVSS No. 111. Also, the fact that the driver's view may have been obstructed supports the need to establish minimum sound requirements for HVs and EVs so that pedestrians can detect when those vehicles are pulling out or approaching in situations in which the pedestrian is potentially obscured from the driver's view.

Fatalities

The Fatality Analysis Reporting System (FARS) contains a census of all traffic fatalities. HVs and EVs that struck and killed a pedestrian were identified using the Vehicle Identification Numbers (VINs) contained in the 2001 through 2009 FARS files. During this period, there were 53 pedestrian fatalities attributed to crashes involving 47 HVs and three EVs. Almost all of these fatalities (47 of the 53) involved vehicles that were identified as passenger vehicles. In 2008, there were 10 HVs or EVs that struck and killed 10 pedestrians, and in 2009, there were 11 HVs or EVs that struck and killed 11 pedestrians.

However, these fatalities are not included in the target population for analysis under this rulemaking for two reasons. The first is that pedestrian fatalities are not as likely to occur at low speeds for which the rate of HV pedestrian collisions is significantly higher than collisions between ICE vehicles and pedestrians. Today's final rule establishes minimum sound requirements for hybrid and electric vehicles operating at speeds up to 30 km/h (18.6 mph). A majority of pedestrian fatalities occur when the vehicle involved in the collision is not travelling at a low speed. Overall, 67 percent of the pedestrian fatalities involving HVs or EVs and with known speed limits occurred at a speed limit above 35 mph.

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For all pedestrian fatalities with known speed limits, 62 percent occurred at a speed limit above 35 mph and 61 percent of those

involving passenger vehicles occurred at a speed limit above 35 mph.

32

The goal of this rule is to prevent injuries to pedestrians that result from pedestrians being unable to hear nearby hybrid and electric vehicles operating at low speeds. At speeds of 35 mph and above, at which a majority of fatal crashes involving pedestrians occur, it is very unlikely that lack of sound is the cause as the sound levels produced by hybrid and electric vehicles at those speeds are the same as the sound levels produced by ICE vehicles. Establishing minimum sound requirements for hybrid and electric vehicles operating at speeds up to 30 km/h is expected to prevent injury crashes but not necessarily have an impact on those crashes involving pedestrian fatalities, based on existing data.

31

For those pedestrian fatalities that occurred on roads with a posted speed limit of 35 mph or less, we do not have any data on actual travel speed of the vehicles involved. Therefore, we are not able to tell if the vehicles involved were travelling at a speed at which they would be required to meet the requirements of the final rule.

32

Data particularly tied to other speeds, such as 20 mph, is not available because of the structure of the databases used,

i.e.,

the relevant data variable is whether the speed limit was above or below 35 mph at the crash location.

The second reason is that the rate of pedestrian fatalities per registered vehicle for HVs and EVs is not larger (and is in fact smaller) than that for ICE vehicles. Using 2008 data, the fatality rate for pedestrians in crashes with HVs and EVs is 0.85 fatalities per 100,000 registered vehicles, and the corresponding rate for ICE vehicles is 1.57 per 100,000 vehicles.

There also could be fatalities involving HVs and EVs that occur in non-traffic crashes in places such as driveways and parking lots. However, a comprehensive search for HVs and EVs involved in pedestrian fatalities could not be undertaken because NHTSA's Not in Traffic Surveillance (NiTS) system does not provide VINs, and a search for model names that indicate hybrid or electric vehicles did not identify any crashes involving pedestrian fatalities.

Low-Speed Vehicles

NHTSA has no data on pedestrian or pedalcyclist crash rates for low-speed vehicles due to the low rate of sales of these vehicles as a percentage of the light vehicle fleet. NHTSA also has not found any examples of crashes involving LSVs and pedestrians or pedalcyclists that appear to be caused by the lack of sound in LSVs. However, we assume that the safety problem with these vehicles will be similar to that for HVs based on the acoustic profile of these vehicles.

Need for Independent Mobility of People Who Are Visually-Impaired

In addition to addressing the safety need in the traditional sense of injuries avoided as a result of preventing vehicle-pedestrian crashes, NHTSA believes it is important to note another dimension of safety that should be taken into account with respect to pedestrians who are blind or visually-impaired. Pedestrians who are blind or visually-impaired need to be able to travel independently and safely throughout their communities without fear and risk of injury, both as a result of collisions with motor vehicles and as a result of other adverse events in the environments they must negotiate. To a far greater extent than is the case for sighted people, vehicle sounds help to define a blind or visually-impaired person's environment and contribute to that person's ability to negotiate through his/her environment in a variety of situations.

33

33

National Federation of the Blind (2011) How People Who are Blind Use Sound for Independent Travel, memorandum to the docket, NHTSA-2011-0148-0028, Washington, DC. That memorandum is the source for this information.

The modern white cane and the techniques for its use help the user to navigate and allow sighted people to recognize that a person is blind or visually-impaired. Today, the “structured discovery” method of teaching independent travel for visually-impaired people emphasizes learning to use information provided by the white cane, traffic sounds, and other cues in the environment to travel anywhere safely and independently, whether the individual has previously visited the place or not.

Whether a blind or visually-impaired person uses a white cane or guide dog, the primary purpose of both travel tools is to help the blind traveler identify and/or avoid obstacles in his or her path using the sense of touch. The remaining information needed by a blind or visually-impaired person to safely and independently travel is provided primarily through the sense of hearing.

When traveling with a white cane or guide dog, the primary sound cue used by blind pedestrians is the sound of vehicle traffic, which serves two purposes: navigation and collision avoidance. Navigation involves not only ascertaining the proper time to enter a crosswalk and maintain a straight course through an intersection while crossing, but also the recognition of roadways and their traffic patterns and their relationship to sidewalks and other travel ways a blind or visually-impaired person might use.

Sound emitted by individual vehicles, as opposed to the general sound of moving traffic, is critical. The sound of individual vehicles helps to alert blind travelers to the vehicle's location, speed, and direction of travel. For example, a blind or visually-impaired person moving through a parking lot can hear and avoid vehicles entering or exiting the lot or looking for parking spaces; a blind person walking through a neighborhood can hear when a neighbor is backing out of a driveway. The vehicle sound also indicates to a blind or visually-impaired pedestrian whether a vehicle is making a turn, and if so, in which direction. The sound of individual vehicles also allows the blind traveler to detect and react to unusual or unexpected vehicle movement. The sound of a vehicle that has an activated starting system but is stationary (usually referred to as “idling” for vehicles with internal combustion engines) alerts the blind or visually-impaired traveler to the fact that the vehicle is not simply parked and that it may move at any moment. If a blind person is approaching a driveway and notes a vehicle that is stationary but running he or she will wait for the vehicle to pull out, or for an indication that it will not, for example by noting that the vehicle remains stationary for some time, indicating that the driver has no immediate plans to move.

In the NPRM, the agency described how the acoustic cues provided by vehicles help blind pedestrians discern changes in the road-way, determine whether an intersection has a traffic control device, and navigate intersections with unusual characteristics such as three-way intersections or roundabouts. The sounds made by traffic including the sounds of idling vehicles allow blind pedestrians to determine when it is safe to cross the street and maintain a straight travel path while walking through the intersection.

Using the white cane or guide dog and the sound of traffic, people who are blind or visually-impaired have been able to navigate safely and independently for decades. Blind and visually-impaired people travel to school, the workplace, and throughout their communities to conduct the daily functions of life primarily by walking and using public transportation. Safe and independent pedestrian travel is essential for blind or visually-impaired individuals to obtain and maintain employment, acquire an education, and fully participate in community life. Short of constantly traveling with a human companion, a blind or visually-impaired pedestrian simply cannot ensure his or her own safety or navigate effectively without traffic sound. To the extent that there are more and more HVs and EVs on the road that are hard to

detect, people who are blind or visually-impaired will lose a key means—the sound of traffic—by which they determine when it is safe to cross streets, but also by which they orient themselves and navigate safely throughout their daily lives, avoiding dangers other than automobiles.

C. Research on Vehicle Emitted Sounds and Detectability

Early Research on Quiet Vehicles and Public Meeting

NHTSA began collaborating with a working group within the Society of Automotive Engineers International (SAE) in August 2007 to identify effective ways to address the safety issue of quiet hybrid and electric vehicles. This working group included representatives from the Alliance of Automobile Manufacturers, Global Automakers, the visually impaired community and NHTSA.

On June 23, 2008, NHTSA held a public meeting to bring together government policymakers, stakeholders from the visually impaired community, industry representatives, and public interest groups to discuss the technical and safety policy issues associated with hybrid vehicles, electric vehicles, and quiet internal combustion engine (ICE) vehicles, and the risks they present to visually impaired pedestrians. After this public meeting, NHTSA issued a research plan to investigate hybrid and electric vehicles and pedestrian safety.

34

The objectives of the research plan were to identify critical safety scenarios for visually impaired pedestrians, identify requirements for blind pedestrians' safe mobility (emphasizing acoustic cues from vehicles and ambient conditions), identify potential countermeasures, and describe the countermeasures' advantages and disadvantages.

34

A copy of the research plan is available at

www.regulations.gov

(Docket No. NHTSA-2008-0108-0025).

In 2009 NHTSA issued the report “Incidence of Pedestrian and Bicyclist Crashes by Hybrid Electric Passenger Vehicles,” discussed in Section II.B of this notice, and a report titled “Research on Quieter Cars and the Safety of Blind Pedestrians, A Report to Congress.”

35

The report to Congress briefly discussed the quieter vehicle safety issue, how NHTSA's research plan would address the issue, and the status of the agency's implementation of that plan.

35

Research on Quieter Cars and the Safety of Blind Pedestrians, A Report to Congress. U.S. Dept. of Transportation, Washington, DC, October 2009, available at

http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2010/RptToCongress091709.pdf

.

In 2010 through 2014 the agency continued relevant quiet car research as briefly discussed below.

Phase 1 Research

In April 2010, NHTSA issued a report that began addressing the tasks listed in the research plan. This report, titled “Quieter Cars and the Safety of Blind Pedestrians: Phase I,” documents the overall sound levels and general spectral content for a selection of ICE vehicles and HVs in different operating conditions, evaluates vehicle detectability for two background noise levels, and considers the viability of countermeasure concepts categorized as vehicle-based, infrastructure-based, and systems requiring vehicle-pedestrian communications.

36

36

Garay-Vega, et al. (2010) Quieter Cars and the Safety of Blind Pedestrians: Phase I, Report No. DOT HS 811 304, U.S. Dept. of Transportation, Washington, DC. Available at

http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2010/811304rev.pdf

.

The results show that the overall sound levels for the HVs tested are noticeably lower at low speeds than for the ICE vehicles tested. Overall, study participants were able to detect any vehicle sooner in the low ambient noise condition. ICE vehicles tested were detected sooner than their HV counterpart vehicles except for the test scenario in which the target vehicle was slowing down. In this scenario, HVs were detected sooner because of the distinctive sound emitted by the regenerative braking system on the HVs. Response time to detect a target vehicle varies by vehicle operating condition, ambient sound level, and vehicle type (

i.e.,

ICE vehicle versus HV or EV mode).

As part of Phase 1 research, NHTSA sought to identify operating scenarios necessary for the safety of visually impaired pedestrians. The researchers identified these scenarios based on crash data, literature reviews, and unstructured conversations with blind pedestrians and orientation and mobility specialists. Scenarios were defined by combining pedestrian vehicle environments, vehicle type, vehicle maneuver/speed/operation, and considerations of ambient sound level. The operating scenarios identified in Phase 1 were: Vehicle approaching at low speed; vehicle backing out (as if coming out of a driveway); vehicle travelling in parallel and slowing (like a vehicle that is about to make a turn); vehicle accelerating from a stop; and a vehicle that is stationary.

In Phase 1, NHTSA also compared the auditory detectability of HVs and ICE vehicles by pedestrians who are legally blind. Forty-eight independent travelers, with self-reported normal hearing, listened to binaural

37

audio recordings of two HVs and two ICE vehicles in three operating conditions, and two different ambient sound levels. The operating conditions included a vehicle: Approaching at a constant speed (6 mph); backing out at 5 mph; and slowing from 20 to 10 mph (as if to turn right). The ambient sound levels were a quiet rural (31.2 dB(A)) and a moderately noisy suburban ambient (49.8 dB(A)). Overall, participants took longer to detect the two HVs tested (operated in electric mode), except for the slowing maneuver. Vehicle type, ambient level, and operating condition had a significant effect on response time.

37

Binaural recordings reproduce the acoustic characteristics of the sound similar to how a human perceives it. Binaural recordings reproduce a more realistic three dimensional sensation than conventional stereo and are intended for playback through headphones, rather than loudspeakers.

Table 5 shows the time-to-vehicle arrival at the time of detection by vehicle type, and ambient condition. Considering all three independent variables, there was a main effect of vehicle, vehicle maneuver, and ambient sound level. Similarly, there were interaction effects between vehicle type and ambient, vehicle type and maneuver, ambient and vehicle maneuver, and a three way interaction between ambient, vehicle type and vehicle maneuver.

Table 5—Average Time-to-Vehicle Arrival by Scenario, Vehicle Type, and Ambient Sound

Scenario

Low ambient

HVs

ICE

vehicles

High ambient

HVs

ICE

vehicles

Approaching at 6 mph

4.8

6.2

3.3

5.5

Backing out at 5 mph

3.7

5.2

2.0

3.5

Slowing from 20 to 10 mph

2.5

1.3

2.3

1.1

The Phase 1 research showed that HVs were more difficult for pedestrians to detect by hearing than ICE vehicles. The Phase 1 research report also discussed various countermeasures to mitigate pedestrian safety risks associated with quiet vehicles. The Phase 1 report also concluded that a vehicle-based audible alert signal was the countermeasure that both provided all the necessary information to blind pedestrians to make safe travel decisions and produced benefits for other pedestrians and for pedalcyclists.

Phase 2 Research

In October 2011 NHTSA released a second report examining issues involving hybrid and electric vehicles and blind pedestrian safety titled “Quieter Cars and the Safety of Blind Pedestrians, Phase 2: Development of Potential Specifications for Vehicle Countermeasure Sounds.”

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The Phase 2 research developed various methods to specify a sound to be used as a vehicle-based audible alert signal that could be used to provide information at least equivalent to the cues provided by ICE vehicles, including speed change, and evaluated sounds using human factors testing to examine whether the sounds could be detected and recognized as vehicle sounds. This research used acoustic data acquired from a sample of ten ICE vehicles to examine the sound levels at which synthetic vehicle sounds used could be set, and used psychoacoustic models to examine issues of detectability and masking of ICE-like sounds and alternative sounds, and also included a human factors study to examine the detectability of synthetic sounds.

38

Garay-Vega, et al. (2011) Quieter Cars and the Safety of Blind Pedestrians, Phase 2: Development of Potential Specifications for Vehicle Countermeasure Sounds, Report No. DOT HS 811 496. Dept. of Transportation, Washington, DC. Available at

http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2011/811496.pdf

.

The methods for specifying sounds discussed in the Phase 2 final report assumed that the vehicle acoustic countermeasure should:

• Provide information at least equivalent to that provided by ICE vehicles, including speed change; and

• Provide for detection of a vehicle in residential, commercial, and other suburban and urban environments in which blind pedestrians would expect to be able to navigate using acoustic cues.

Note:

Human factors tests for Phase 2 were conducted in an ambient of approximately 58-61 dB(A).

As part of the Phase 2 research, Volpe conducted a human factors study to compare the auditory detectability of potential sounds for hybrid and electric vehicles operating at a low speed and how those sounds compared to an ICE control vehicle. The human factors testing in Phase 2 suggested that synthetic sounds resembling an ICE produce similar detection distances as actual ICE vehicles. In some instances, the results indicated that synthetic sounds designed according to psychoacoustic principles can produce double the detection distances relative to the reference vehicle. The results also suggested that synthetic sounds that contain only the fundamental combustion noise are relatively ineffective. None of the analyses found a significant effect of vision ability.

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Participants who were legally blind, on average, were no better or worse than sighted participants in detecting the approach sounds.

39

All participants were required to wear a blindfold during the study.

Phase 3 Research

In order to develop possible test procedures and requirements for an FMVSS proposing to establish minimum acoustic requirements for hybrid and electric vehicles, NHTSA initiated a third phase of research to develop an objective, repeatable test procedure and objective specifications for minimum sound requirements. NHTSA's Vehicle Research and Test Center (VRTC), as part of its effort to develop a test procedure, conducted acoustic measurements and recordings of several HVs and EVs and those vehicle's ICE pair vehicles.

40

Volpe used these recordings as well as data from the Phase 1 and Phase 2 research to identify parameters and criteria for sounds to be detectable and recognizable as a motor vehicle.

40

Evans and Harris. (2012) Quieter Vehicle Performance Test Development Research Report, U.S. Dept. of Transportation, Washington, DC. Available at

www.regulations.gov

, Document ID: NHTSA-2011-0148-0047.

VRTC Acoustic Measurements

The primary focus of Phase 3 research conducted by VRTC was to develop an objective and repeatable test procedure to measure vehicle-emitted sound. This work consisted mainly of evaluation of the new SAE J2889-1,

Measurement of Minimum Noise Emitted by Road Vehicles,

test method, and several variations used to test operating conditions that were not included in SAE J2889-1, and development of a practical test procedure for collecting test track acoustic data from HVs, EVs and ICE vehicles. The data collected was then evaluated to begin establishing potential performance criteria. The draft version of SAE J2889-1 used by VTRC included recommended procedures for measuring minimum sound pressure levels of vehicle-emitted sound but did not include any recommended performance requirements for minimum levels of vehicle-emitted sound. SAE J2889-1 was still in draft form at the start of the research, but the version published in September 2011 was not significantly different from the draft.

The research was conducted using three HVs, one EV, and four ICE vehicles. The vehicles were used to gather sample data on the difference in sound pressure levels between ICE sounds and EV or HV sounds. VRTC also gathered data to determine how synthetic vehicle sounds emitted from speakers projected around the vehicle, as referred to as the directivity of the sound, and sound quality levels. Some of the hybrid and electric vehicles were tested with multiple alert sounds. Some of the hybrid and electric vehicles were also tested with no alert sound at all, to examine the difference between the sound pressure level produced by hybrid and electric vehicles and ICE vehicles.

One of the purposes of the Phase 3 acoustic measurements was to gather additional data on the difference in sound levels between ICE vehicles and EVs and HVs operating in electric mode. For the pass-by tests at 10 km/h in Phase 3, the ICE vehicles were between 6.2 and 8.5 dB(A) louder than the EV/

HVs without added sound. At 20 km/h the difference between the HV/EVs and ICE vehicles varied, but the average delta was 3.5 dB(A) louder for the ICE vehicles. At 30 km/h the sound levels of the HV/EVs approached the levels of the ICE vehicles and the individual measurements for the two types of vehicles have considerable overlap. Table 6 shows the results of HV/EV vehicles with no sound alert as compared to their ICE counterparts.

Table 6—Pass-By Sound Level for HV/EV Vehicles Without Alert Sound Versus Counterpart ICE Vehicles

Manufacturer

Speed, km/h

HV/EV Sound Level, dB

ICE Sound Level, dB

ICE minus HEV/EV, dB

Nissan

10

50.5

56.6

6.1

20

60.0

62.3

2.3

30

66.5

68.1

1.6

Prototype Vehicle G

10

51.4

59.9

8.5

20

60.5

63.1

2.6

30

67.0

67.5

0.5

Prototype Vehicle H

10

51.2

59.7

8.5

20

59.3

64.5

5.2

30

65.3

69.2

3.9

Average

10

51.0

58.7

7.7

20

59.9

63.3

3.4

30

66.3

68.3

2.0

The measurements from the startup and stationary but active scenarios were used to measure the directivity of the vehicles' sound. The purpose of measuring the directivity pattern of the vehicles was to compare the directivity pattern of ICE vehicles to those hybrid and electric vehicles equipped with a speaker system. For the ICE vehicles, the sound pressure level behind the vehicle was 6 to 10 dB lower than that directly in front of the vehicle. For the hybrid and electric vehicles with a speaker system, the sound level behind the vehicle was 12 to 15 dB lower behind the vehicle. There was a systematic difference from left to right for some vehicles, particularly with an artificial sound.

Volpe Acoustic Analysis

As another part of the Phase 3 research, Volpe conducted an analysis of existing acoustic data and data collected during the previously mentioned VTRC testing to develop recommendations for performance requirements for minimum levels of vehicle emitted sound to be proposed in the NPRM. This work consisted of examining the frequency ranges, minimum sound levels for selected one-third octave bands, and requirements for broadband noise and tones as possible criteria for setting minimum requirements for vehicle-emitted sound. Evaluations were conducted using a loudness model

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to determine when the sounds might be detectable in a given ambient. Of the several different loudness models examined by Volpe, Moore's Loudness provided the most pertinent information about the perceived loudness and detectability of a sound. Two approaches were used to identify potential detectability specifications for alert sounds to be included in the NPRM: (1) Sound parameters based on a loudness model and detection distances and (2) sound parameters based on the sound of ICE vehicles.

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Loudness models are computer simulations used to estimate the minimum sound levels needed for alert sounds to be detectable in the presence of ambient noise.

Volpe's work in developing the sound specifications based on a loudness model and detection distances was guided by several aspects of the agency's Phase 1 and Phase 2 research. Volpe analyzed the acoustic data of the sounds used in the human factors research in Phase 2 from a psychoacoustic perspective to determine the loudness of the sounds and whether the sounds would be detectable in several different ambient environments. Because the response of the study participants in the human factors experimentation in Phase 2 varied significantly due to variations in the ambient,

42

Volpe determined that any analysis of sounds using a loudness model should use a synthetic ambient that did not vary with respect to the frequency profile or overall sound pressure level. Volpe used a synthetic ambient sound with the loudness model during Phase 3 in developing the specifications contained in the NPRM.

42

Garay-Vega, et al. (2011) Quieter Cars and the Safety of Blind Pedestrians, Phase 2: Development of Potential Specifications for Vehicle Countermeasure Sounds, Report No. DOT HS 811 496. Dept. of Transportation, Washington, DC. Available at

http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2011/811496.pdf

.

This research showed that pedestrians' ability to detect synthetic sounds would be maximized if the alert signal contains detectable components over a wide frequency range. The research also explored how tones and broadband content could enhance the detectability of synthetic alert sounds. The report used acoustic data for directivity to estimate minimum sound levels for `reverse' or `backing' maneuvers. Volpe then used the results of this analysis of the detectability of sounds as estimated by psychoacoustic models to make recommendations for potential minimum sound levels for the NPRM.

In addition to using psychoacoustic models to develop recommendations for minimum sound specifications, Volpe created a set of minimum sound specifications based on the sound produced by ICE vehicles. Volpe considered multiple minimum sound specifications in an attempt to derive at the most optimal approach for defining sound specification requirements in order to provide recommendations for a variety of sound specifications for NHTSA to seek comment on in the NPRM. Volpe created the specification based on the sound produced by ICE vehicles (using data captured during Volpe's Phase 2 research) and recordings of vehicles provided by automobile manufacturers. Volpe aggregated this data to create minimum acoustic specifications based on the mean sound levels of ICE vehicles and the mean sound levels of ICE vehicles minus one standard deviation.

Agency Research and Analysis Conducted Since the NPRM

After the NPRM was issued, NHTSA conducted research to examine additional aspects of minimum sound requirements for hybrid and electric vehicles. The research involved human

factors testing and acoustic modeling to examine the detectability of sounds with different acoustic characteristics. The research also involved acoustic measurement of heavy-duty vehicles and motorcycles, analysis of indoor testing conducted by Transport Canada, and additional light vehicle testing to refine the test procedure proposed in the NPRM. The research is documented in multiple separate research reports and is summarized below. In some cases, as identified below, more details of the research are provided in the appropriate sub-sections of Section III of this preamble. In those cases, the agency discusses the important aspects of the research that were utilized to make decisions finalized in this rule.

Human Factors Research and Acoustic Modeling

In the NPRM, NHTSA proposed minimum sound pressure levels for a specific set of one-third octave bands that included low frequency bands (315, 400, and 500 Hz) and high-frequency bands (2000, 2500, 3150, 4000, and 5000 Hz) for various operating conditions. These proposed specifications for minimum sound pressure levels were identified based on a psychoacoustic loudness modeling approach and safe detection distances.

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After the NPRM was published, the agency conducted a study to quantify the differences between predicted detection levels of vehicle sounds in the presence of an ambient (as indicated by the loudness model) and the actual responses by participants listening to these vehicle sounds through headphones. This was done in order to evaluate the accuracy of the psychoacoustic model in predicting when sounds would be detected. The study also explored the effect of different factors such as the number of bands at threshold, adjacent and non-adjacent bands, and signal type (

e.g.,

pure tones, bands of noise).

44

In addition to the human factors study, Volpe also conducted an analysis of acoustic data in order to predict the probability that a sound would be detected in different ambients as the number of one-third octave bands making up the sound changes.

43

Hastings, et al. (2012). Research on Minimum Sound Specification for Hybrid and Electric Vehicles. Docket NHTSA-2011-0148-0048.

44

Hastings, et al. Detectability of Alert Signals for Hybrid and Electric Vehicles: Acoustic Modeling and Human Subjects Experiment. (2015) Washington, DC: DOT/NHTSA.

The key performance metrics for the human factors study were the response time and associated time-to-vehicle arrival. Response time is the elapsed time, in seconds, from the start of the trial to the instant the participant presses the push-button as an indication he/she detected the target signal. The time-to-vehicle arrival is the elapsed time, in seconds, from first detection of a target signal to the instant the vehicle passes the pedestrian location. The detection distance is the separation between the vehicle and the pedestrian location at the moment of detection. The detection distance can be computed from the time-to-vehicle arrival and vehicle speed. Signals meeting the minimum sound levels, computed according to the approach described in the NPRM, are expected to be detectable at least 2.0 seconds or 5 meters away (for a vehicle approaching at 10 km/h). Table 7 shows the time-to-vehicle arrival and detection distances for the signals examined in this study. The signals used in the study included sounds developed by Volpe to test different hypotheses involving the detection model, recordings of prototype synthetic sounds provided by vehicle manufacturers, and a recording of an ICE vehicle. The “Source” column in Table 7 describes the origin of each sound.

Table 7—Sound Stimuli Tested

Signal ID

Significant component frequencies, Hz

Levels, dB(A)

Source

Comment

Time-to-vehicle arrival, s

Vehicle distance at detection, m

3

315, 400, 500, 630, 2000, 2500, 3150, 4000, 5000

Threshold

Simulation

Tone @315 Hz, TNR 9 dB

4.9

13.6

6

315, 400, 500, 630, 2000, 2500, 3150, 4000, 5000

Threshold

Simulation

Tone @630 Hz, TNR 9 dB

4.3

11.9

9

315, 400, 500, 630, 2000, 2500, 3150, 4000, 5000

Threshold

Simulation

Tone @2500 Hz, TNR 9 dB

4.5

12.5

10

315, 400, 500, 630, 2000, 2500, 3150, 4000, 5000

Threshold

Simulation

NNPRM + 630 Hz

4.4

12.2

11

315

Threshold

Simulation

Single Noise Band

2.3

6.4

12

630

Threshold

Simulation

Single Noise Band

2.9

8.1

13

2500

Threshold

Simulation

Single Noise Band

2

5.6

14

315, 400, 500, 2000, 2500, 3150, 4000, 5000

Threshold

Simulation

NPRM

4.3

11.9

15

50 to 10,000

Threshold

Simulation

Noise in all Bands

4.6

12.8

17

315, 400, 500

46, 54, 48

Prototype Recording

ASG as Recorded (No calibration)

5.8

16.1

18

315, 400, 500, 2000, 2500, 3150, 4000, 5000

Threshold

Prototype Recording

ASN (Calibrated to match NPRM)

4.5

12.5

19

2500

56

Prototype Recording

ASN as Recorded (No calibration)

5.8

16.1

20

315, 400, 500, 2000, 2500, 3150, 4000, 5000

Threshold

Prototype Recording

ASV Sound4 (Calibrated to match NPRM)

6.7

18.6

23

4000, 5000, 6300, 8000, 10000

37, 36, 34, 32, 31

ICE Recording

ASF ICE (No Calibration)

3.1

8.6

25

315, 400, 500

Threshold

Simulation

Low Frequency Noise

4.2

11.7

26

315, 630, 2000, 5000

Threshold

Simulation

Non-adjacent Noise

4.5

12.5

27

630, 800, 1000, 1250, 1600

Threshold

Simulation

Mid-frequency Noise

3.7

10.3

28

800, 2500

39, 45

Simulation

1 below threshold, 1 at threshold

2.2

6.1

29

800, 2500

45, 39

Simulation

both below threshold

1.4

3.9

30

800, 2500

50, 50

Simulation

1 ~ threshold, 1 above threshold

3.6

10.0

31

2000, 2500, 3150, 4000, 5000

Threshold

Simulation

High Frequency Noise

3.2

8.9

32

315

Threshold

Simulation

Pure Tone

3.1

8.6

33

630

Threshold

Simulation

Pure Tone

2.9

8.1

34

2500

Threshold

Simulation

Pure Tone

2.4

6.7

The data showed that all signals tested in the study exceeded the 2.0-second detection criterion except for signal 29, which was detected 1.4 seconds before pass-by.

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Exceeding the 2.0-second detection criterion was expected for signals with content in more than one one-third octave band, since the modeled thresholds were based on a signal with content in a single band. Content in multiple one-third octave bands could increase the time-to-vehicle arrival if subjects aggregated the energy across bands or if they utilized a `best' single band strategy. That is, with more one-third octave bands, the signal can be more easily detected either because it is stronger overall or because, given the many possible random factors that could affect detectability, more components creates a greater probability that at least one band will be easier to detect.

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Signal 29 had two components, and the levels were set below the minimum detection thresholds.

An ICE vehicle (signal 23), without calibration to minimum one-third octave band levels for detection used in the NPRM, was detected 3.1 seconds away on average. Two prototype alert signals (signals 17, 19), without calibration to minimum one-third octave band levels for detection used in the NPRM, were detected 5.8 seconds away. In general, signals with a pure tone (signals 32, 33, 34) were detected sooner than signals with a single band of noise at the same frequency (signals 11, 12, 13). For example, the average time-to-vehicle arrival was 3.1 seconds for a pure tone at 315 Hz and 2.3 seconds for a single band of noise at the same frequency. A statistical analysis also found that the interaction of sound type (tones or noise) and frequency was significant.

The study results indicated that, except for frequency sensitivity for high frequency components, the modeling approach for determining detection thresholds was conservative, meaning that the study participants were able to detect sounds sooner than predicted by the model. In order to correct for frequency sensitivity differences and to develop the best agreement between modeled detection thresholds and those of the participants so that the minimum one-third octave band levels for detection in the final rule more closely align with pedestrians' ability to detect sounds in the real world, Volpe performed a linear regression to reconcile the predicted detection values in the model and the performance of the participants in the experiment.

In order to ensure that the model was as predictive of real-world experience as possible, that is, in order to obtain the best agreement between modeled detection thresholds and those of the participants, and also to correct for frequency sensitivity differences, Volpe did a series of linear regressions using different loudness metrics. The best agreement between modeled and actual participant detection times occurred when a detection threshold of 0.079 sones

46

per ERB was used

47

(see Figure 1). The R-squared value achieved for this model was 0.72, indicating that the model performs well on average although, as anticipated, outcomes are not always exactly the same due to random variation and other differences between the model predictions and participant performance. Thus, the agency chose to use the detection threshold of 0.079 sones per ERB in the Moore's model as the basis for deriving the revised minimum levels for each of the one-third octave bands in the final rule.

46

Sone is a unit of subjective loudness on a linear scale. The Moore's Loudness model used by the agency in the NPRM and this final rule utilizes loudness (in sones) and partial loudness (in sones per equivalent rectangular bandwidth or “ERB”) parameters as a basis for determining thresholds,

i.e.,

minimum sound levels, required for vehicle detection.

47

Hastings A.; and McInnis, C. “Detectability of Alert Signals for Hybrid and Electric Vehicles: Acoustic Modeling and Human Subjects Experiment” Docket NHTSA-2011-0148. Washington, DC: DOT/NHTSA.

ER14DE16.000

The agency also conducted an analysis of acoustic recordings to evaluate the detectability of signals with varying numbers of non-adjacent components in the presence of additional ambient conditions different from the standardized ambient used to develop the one-third octave band minimum levels for detectability in the NPRM or this final rule. The analysis provides an estimate of how often pedestrians would be able to detect a sound signal in a 55 dB(A) ambient, with expected spectral variation, as a function of the number of one-third octave bands meeting the revised minimum thresholds.

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Ambient data were collected at 17 locations along Centre Street in Newton, Massachusetts, signalized and stop-controlled intersections (some with relatively high traffic volume and some removed from the main road), one-way streets, and side streets or driveways. The spectral shape of the ambient varies from sample to sample, as would be expected given the different locations in which they were collected. Some samples are dominated by low frequency content while other samples are dominated by high frequency content or have a mix of high and low frequency content. Each ambient sample was normalized to an overall sound pressure level of 55 dB(A), so that the effect of the spectral content of each ambient on the detectability of a signal could be examined in isolation from other variables. This analysis differs from the modeling approach used to develop the minimum one-third octave band levels for detection in the NPRM and the final rule because that approach used a single ambient that was chosen for consistency in development of minimum standards. NHTSA refers to the resistance to masking of a signal evaluated using this analysis as the “robustness” of the signal. Signals evaluated for robustness contained from one to seven non-adjacent components within the 315 to 5000 Hz frequency range. In most cases, these signals were scaled so that the components just met the minimum one-third octave band levels for detectability derived from the human factors study.

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For practical reasons, this analysis is limited in that it includes 17 measurement locations for the ambient that are in one State, Massachusetts. Also, ambient samples were not categorized or weighted according to `preferred crossable' opportunities for pedestrians.

This analysis predicted that, as ambient conditions vary, the probability that at least one component is detectable increases with increasing number of components when each component is set to the minimum detection levels calculated based on the human factors study. This is true for all operating conditions. For signals with content in 1, 2, 3, 4, 5, 6, and 7 one-third octave bands, the predicted probabilities were about 55, 81, 93, 97, 98, 100, and 100 percent, respectively. The analysis indicates that there is a rapid increase in detectability as the number of components increases from 1 band to 4 bands when each band is set at the specified minimum detectable level. Additional bands beyond 4 do not appear to increase the detectability level significantly. An eight-band sound was not included in the analysis because eight non-adjacent one-third octave bands do not fit in the frequency range over which we are establishing minimum requirements in the final rule. This analysis also showed that some signals with content in only 2 one-third octave bands are expected to be detected with the same frequency in multiple ambients as signals with content in 4 one-third octave bands. Because signals with content in 2 one-third octaves bands could be equally detectable as sounds with content in 4 one-third octave bands the agency decided to include minimum requirements for content in either 2 or 4 one-third octave bands in the final rule.

Heavy Vehicle and Motorcycle Testing

The research NHTSA conducted prior to the NPRM focused exclusively on

light vehicles. However, since issuing the NPRM, the agency has conducted some acoustic measurements on hybrid and electric heavy-duty vehicles (GVWR over 10,000 lb.) and electric motorcycles.

49

The test protocol used for those measurements followed procedures in SAE-2889-1 (May 2012).

49

Hastings, et al. Acoustic Data for Electric Heavy Vehicles and Electric Motorcycles. (2014) DOT/NHTSA.

Two electric motorcycles were tested at the Transportation Research Center in Columbus, Ohio, on a test surface conforming to ISO 10844-2011 specifications. NHTSA was able to apply the proposed test procedure to the motorcycles without major issues.

50

The overall sound pressure levels for a 2012 model Brammo Enertia were 57.0, 63.2 and 66.5 dB(A) for the 10, 20, and 30 km/h pass-by, respectively. The overall sound pressure levels for a 2012 model Zero S were between 6.2 to 7.9 dB lower with 49.1, 57.0 and 59.6 dB(A) for the 10, 20, and 30 km/h pass-by, respectively.

50

One notable change is that the motorcycles were run just to the right of the center of the lane with respect to the direction of travel. This was done so the motorcycles' tires were not rolling on the painted center line, since it was important to keep the tires on the portion of the test track which had pavement meeting the ISO specification (the painted center line is not intended to meet the ISO specification.) Additionally, motorcycles were not tested in reverse since they did not have reverse capabilities.

The one-third octave band levels for the two motorcycles were computed and compared to the minimum levels needed for detection (as determined in NHTSA's research described in Section II.C

51

) in the frequency range from 315 Hz to 5000 Hz. Results for the 2012 Brammo Enertia show that the measured levels were equal or greater than the minimum levels in two bands for the 10 km/h pass-by and in three bands for the 20 km/h pass-by. Sound levels for the Enertia for the 30 km/h pass-by did not meet the minimum levels for detection in any one-third octave bands from 315 Hz to 5000 Hz. Sound levels for the 2012 Zero S did not meet the minimum levels for detection in any of the bands for all pass-by tests (

i.e.,

10, 20, and 30 km/h). While there is an appreciable difference between the two models tested, these results indicate that both models operate quietly over all or part of the range of speeds up to 30 km/h. As discussed in Section III.B, the agency has determined that, as with other types of hybrid and electric vehicles, it is appropriate that the requirements of this final rule should apply to hybrid and electric motorcycles.

51

Hastings, et al. Detectability of Alert Signals for Hybrid and Electric Vehicles: Acoustic Modeling and Human Subjects Experiment. (2015) Washington, DC: DOT/NHTSA. As described in this report, the minimum levels needed for detection were determined using an acoustic loudness model that was adjusted for actual human hearing responses to vehicle sounds and other sounds by using the results of a series of human factors experiments conducted by Volpe for NHTSA.

NHTSA also collected acoustic data for a pure electric heavy vehicle (Navistar eStar two-axle delivery van) on a surface compliant with ISO 10844 and suitable for heavy vehicles. No issues were encountered in applying the test protocol to the heavy vehicle tested. It is important to note that only this one delivery truck was tested. The agency was unable to obtain electric or hybrid heavy-duty vehicles with different sizes and configurations for testing. The overall sound pressure levels for the Navistar eStar were 55.4, 64.5, 73.4, and 75.2 dB(A) for the stationary, 10, 20, and 30 km/h pass-by scenarios, respectively. The acoustic measurements for this vehicle were computed and compared to the minimum levels needed for detection in the frequency range from 315 Hz to 5000 Hz.

52

The data showed that the measured one-third octave band levels for the e-Star heavy vehicle are equal to or greater than the minimum levels for detection in seven bands for stationary, nine bands for the 10 km/h pass-by, eight bands for the 20 km/h pass-by, and seven bands for the 30 km/h pass-by. Thus, this vehicle generated appreciable sound at low speeds without the addition of a pedestrian alert system, and we would expect this vehicle to be detectable. However, because this testing was limited to only one electric truck, the agency is not able to reach any general conclusions that hybrid and electric heavy vehicles should be exempt from the final rule.

52

Hastings, et al. Detectability of Alert Signals for Hybrid and Electric Vehicles: Acoustic Modeling and Human Subjects Experiment. (2015) Washington, DC: DOT/NHTSA.

The agency also collected “screening” data for four hybrid and electric heavy-duty vehicles. Screening tests were conducted in the field (not on ISO 10844 sound pads) at convenient locations using portable sound level meters. We note that the test protocol used for the screening tests did not fulfill all the parameters stated in SAE-J2889-1, and the measurements may not have been within the constraints of the SAE standard for acoustic environment, operating conditions, test surface, number of microphones, and microphone position. The results obtained from screening data therefore may deviate appreciably from results obtained using protocols and test conditions that strictly adhere to the SAE standard. Data were collected at three locations, Dayton, Ohio; Washington, DC; and Cambridge, Massachusetts. The four vehicles in the screening tests were all transit buses and included a New Flyer diesel-electric hybrid bus in Washington, DC; a trackless electric trolley bus and a diesel-electric hybrid trolley bus in Dayton, and a Neoplan trackless electric trolley bus in Cambridge. Each vehicle was tested in as many of the applicable operating scenarios (stationary, 10, 20, and 30 km/h pass-by) as possible. However, due to vehicle or site limitations, not all vehicles were tested in all of those operating scenarios.

The screening data showed that the overall levels for these vehicles range from 55.9 to 59.0 dB(A) for a stationary test; 61.7 to 69.3 dB(A) for a 10 km/h pass-by test; and 66 to 70.3 dB(A) for a 20 km/h pass-by test. The acoustic measurements for these vehicles were computed and compared to the NPRM minimum levels for detection in the frequency range from 315 Hz to 5000 Hz, for the eight bands included in the NPRM.

53

The data showed that the measured levels for the heavy vehicles tested are equal to or greater than the minimum levels in five to seven bands for stationary; five to eight bands for the 10 km/h pass-by; two to five bands for the 20 km/h pass-by; and seven bands for the 30 km/h pass-by. The screening data were informative about hybrid and electric medium-duty and heavy-duty vehicle noise levels, but they were not intended to be conclusive, and thus the agency did not determine from this testing that it would be appropriate to exclude medium and heavy vehicles from the final rule.

53

Hastings, et al. Detectability of Alert Signals for Hybrid and Electric Vehicles: Acoustic Modeling and Human Subjects Experiment. (2015) Washington, DC: DOT/NHTSA.

Analysis of Indoor Test Data

NHTSA also analyzed acoustic data measured in hemi-anechoic chambers equipped with a chassis dynamometer.

54

The data acquired at indoor test facilities included measurements of electric, hybrid, and internal combustion engine vehicles. NHTSA's analyses examined ambient noise, repeatability, and reproducibility of the indoor acoustic measurements. Acoustic data were collected at two indoor facilities: The General Motors Milford Proving Grounds (MPG), in Milford, MI and the International Automotive Components (IAC) facility,

in Plymouth, MI. Indoor test data was provided to NHTSA by Transport Canada.

55

Outdoor test data were collected by NHTSA's Vehicle Research and Test Center (VRTC) at the Transportation Research Center (TRC), East Liberty, OH, and NHTSA did a comparison of indoor and outdoor measurements. The dataset available to support these analyses included eight vehicles. Test vehicles were transported between the Milford and Plymouth facilities so that the exact same vehicles were used at both indoor test sites. Vehicle make and model were consistent between indoor and outdoor testing,

56

but the outdoor test results have been aggregated over several testing efforts and do not in all cases represent the exact same test vehicles.

54

Hastings, et al. Analysis of Acoustic Data for Hybrid and Electric Vehicles measured on Hemi-Anechoic Chambers. Washington, DC: DOT/NHTSA. A hemi-anechoic chamber is a specially-designed room with walls that absorb sound waves for better acoustic analysis.

55

Whittal, I.; Jonasch, R.; and Meyer, N. Quiet Vehicle Sounds Test Data (2013) Transport Canada. Docket NHTSA-2011-0148-0321.

56

Indoor results from a 2012 Nissan Leaf were compared to outdoor results from a 2010 Nissan Leaf.

Repeatability at each indoor test site was evaluated by computing the standard error of the mean for each one-third octave band from the sound pressure measurements, considering each measurement as an estimate of the mean for each vehicle. The standard errors for these two indoor test sites were typically around 0.5 to 0.75 dB for the 315 Hz one-third octave band and above. This indicates that about 95 percent of measured one-third octave band levels for a given vehicle and operating speed will be within a range of ±1 to ±1.5 dB and, when estimating a mean value using four samples, the mean value should be within about 0.5 to 0.75 dB of the true mean with 95-percent confidence.

Measurement reproducibility between the two indoor test sites was evaluated by comparing the average values of each vehicle at each one-third octave band for each speed. The differences between sites were about 2 dB on average at 10 km/h and only about 1 dB on average at 20 and 30 km/h. Although the average difference is generally less than 2 dB between the two sites, differences for specific vehicle/speed/frequency pairs are still significant. When considering site-to-site differences, the 95-percent confidence intervals for estimated means range from ±2.5 dB to ±6.7 dB depending on the one-third octave band. Bands at and below 400 Hz consistently have standard deviations greater than 2 dB and bands 500 Hz and above typically have standard deviations less than 2 dB (exceptions being 630 Hz and 800 Hz). The reproducibility between sites appears good. We believe the measurement differences are due to inherent test variability, as discussed in section III.K of this document, and also to differences in each site's dynamometer/tire interaction.

In addition to comparing the two indoor test sites to one another, both facilities were also compared with outdoor measurements made at TRC. Measurement reproducibility between each indoor test facility and the outdoor test facility was evaluated by comparing the average sound pressure levels of each vehicle at each one-third octave band for each speed at the respective sites. Results showed that the indoor facilities tend to have higher sound pressure levels, especially at 20 and 30 km/h. Because the differences are smaller at 10 km/h, it is not likely that the differences in acoustic reflections from the indoor floor and the outdoor pavement are causing the difference. Rather, it is likely that the tire/dynamometer interaction is producing the higher sound pressure levels. Considering confidence intervals of estimated mean values for individual vehicle/speed/frequency pairs, the standard deviation between TRC and MPG was as high as 5 dB and the standard deviation between TRC and IAC was as high as 4.7 dB. Therefore, tolerance values associated with 95-percent confidence intervals would be as large as ±9.8 and ±9.2 dB respectively.

These confidence intervals include site-to-site differences and differences as a result of using different vehicles and in some cases different model years. It is anticipated that this confidence interval would be reduced if identical vehicles were tested. This indoor/outdoor analysis involved only a very limited amount of data and the data in some cases was not from the exact same vehicle. The agency would prefer to conduct additional testing in a more highly controlled fashion to allow for more conclusive results. In the absence of that, we have not changed our position on using outdoor testing as proposed in the NPRM.

Acoustic Measurements of Hybrid and Electric Vehicles

NHTSA's VRTC conducted additional acoustic measures for hybrid vehicles, electric vehicles, low speed electric vehicles, and internal combustion engine (ICE) vehicles to collect additional sound measurements and to evaluate the repeatability of the test procedure proposed in the NPRM.

57

Sound levels were measured while vehicles were stationary and while they were driving or coasting past microphones at constant speeds of 10, 20, and 30 km/h.

57

Garrott, W. R., Hoover, R. L., Evans, L. R., Gerdus, E., and Harris, J. R., “2012 Quieter Vehicle Testing Report: Measured Sound Levels for Electric, Hybrid Electric, and Low Speed Vehicles” Washington, DC, DOT/NHTSA, November 2016.

The repeatability of the measurement of the sound pressure level was assessed by performing multiple tests with one vehicle (a 2010 Ford Fusion) on one surface. The TRC ISO-compliant surface was used for this work and tests were performed twice a month from April to October 2012. Each test consisted of eight individual measurements for each scenario. Results showed that the 95-percent confidence interval of the overall sound pressure level ranged from ±0.7 dB to ±1.9 dB for the various scenarios. There was no significant systematic change in overall sound pressure levels over the six month period.

Data were also collected at different ISO 10844-compliant surfaces to examine test reproducibility. The reproducibility of sound pressure levels was estimated by testing the 2010 Ford Fusion twice on two other ISO-compliant surfaces (at Ford Motor Company Proving Ground in Romeo, Michigan, and at the Navistar Test Track in Fort Wayne, Indiana). The average sound pressure levels for all scenarios on the other ISO surfaces fell within the experimental errors of the average sound pressure levels measured on the TRC ISO surface. The 95-percent confidence interval of site-to-site variation for overall sound pressure level ranged from ±0.6 dB to ±2.1 dB and the 95-percent confidence estimates for reproducibility, including the repeatability of the measurements, ranged from ±1.3 dB to ±2.4 dB.

To determine if acoustic testing locations could include test areas with surfaces that are not ISO-compliant, the agency investigated using correction factors to adjust data from non-ISO-compliant surfaces, the agency compared overall sound pressure levels measured on ISO 10844-compliant surfaces to overall sound pressure levels measured on three other asphalt surfaces of varying characteristics. The alternative surfaces were located at TRC in East Liberty, OH, and included: A new asphalt surface in the vehicle dynamics area; a sealed asphalt surface; and a skid calibration lane. These pavements were appropriate examples of potential test surfaces that are not ISO-compliant to examine the impact that testing using different surfaces may have on measuring vehicle sound.

Overall sound pressure levels on the three asphalt surfaces were compared to the results on the TRC ISO surface using the 2010 Ford Fusion, and an EV with

an active external sound generator, as well as an EV without an active external sound generator. Results showed that one surface tended to produce overall sound pressure levels significantly lower than the ISO-compliant surface at 0 and 10 km/h. Researchers concluded that this was due to greater absorptivity of this asphalt composition. The other two surfaces tended to generate results not significantly different than the ISO-compliant surface when the vehicles were stationary or traveling at 10 km/h. On these surfaces, sound levels increased more rapidly than for the ISO surface as the vehicle speed increased. The overall sound pressure levels at 20 and 30 km/h tended to be significantly higher for these two surfaces compared to the ISO surface. Researchers concluded that these surfaces tended to generate more tire noise than the ISO-compliant surface. An attempt to use the data from the Ford Fusion to normalize the sounds from the different surfaces was unsuccessful. Consequently, we did not conclude that it is feasible to test on surfaces other than an ISO-compliant one.

To examine the sound levels emitted by low speed electric vehicles (LSVs), VRTC tested five of examples of these vehicles. LSVs typically are lighter than EVs and often use different tires, so it was prudent to conduct separate measurements of LSVs rather than assume they are as quiet as EVs. The sound levels produced by the LSVs were very similar to those of the EVs, with the main difference being that four of the LSVs were equipped with back-up beepers of varying sound pressure levels. Other than during reverse acceleration, the LSVs showed overall sound levels with standard deviations ranging from about 1 to 2.5 dB.

To provide data for the agency's analysis of the crossover speed of HVs and EVs, the agency tested additional HVs and one EV as well as a number of ICE peer vehicles (in cases where a peer vehicle was available for the HVs and the EV selected for testing) and compared the ICE peer vehicle test results to the HV and EV results. At 10 km/h, the three HVs tested (none with external sound generators) had an average SPL 2.4 dB lower than their ICE peer vehicles. An EV without an active external sound generator had an average SPL 7.3 dB lower than its ICE peer vehicle. At 20 km/h, the three HVs (none with external sound generators) had an average sound pressure level 1.1 dB lower than their ICE peer vehicle and the EV without external sound had an average sound pressure level of 3.5 dB below its ICE peer vehicle. At 30 km/h the HVs and EV had sound pressure levels that were not significantly different from their ICE peer vehicles. One-third octave band data and comparisons were also reported.

In addition, the agency compared the sound pressure levels of ICE vehicles in motion with their engines running to the same ICE vehicles coasting past the microphones with their engines turned off. These comparisons were made at 10, 20, and 30 km/h. The sound pressure levels for the vehicles with their engines running were an average of 7.9 dB higher than in the coasting (engine-off) condition at 10 km/h (min. 4.3 dB, max. 11.6 dB); 2.2 dB higher than in the coasting (engine off) condition at 20 km/h (min. 0.6 dB, max. 5.7 dB); and 0.9 dB higher than in the coasting (engine off) condition at 30 km/h (min. 0.5 dB; max. 1.7 dB).

D. Notice of Proposed Rulemaking

In the NPRM we proposed to apply the minimum sound requirements to all hybrid and electric passenger cars, light trucks and vans (LTVs), medium and heavy-duty trucks and buses, low speed vehicles (LSVs), and motorcycles, that are capable of propulsion in any forward or reverse gear without the vehicle's ICE operating.

The proposed minimum sound requirements would apply to these HVs and EVs in three circumstances: (1) When operating up to 30 km/h (18 mph), (2) when the vehicle's starting system is activated but the vehicle is stationary,

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and (3) when the vehicle is operating in reverse. The NPRM also contained requirements for the sound produced by hybrid and electric vehicles to increase and decrease in pitch as the vehicle increases and decreases speed so that pedestrians would be able to detect those changes. We proposed a crossover speed of 30 km/h because this was the speed at which tire noise, wind resistance noise, and other noises from the vehicle become the dominant noise and eliminate the need for added alert sounds.

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The NPRM contained minimum sound requirements for the stationary but active condition because the definition of alert sound in the PSEA requires the agency to issue minimum sound requirements to allow pedestrians to detect the operation of nearby hybrid and electric vehicles, including those vehicles that are operating but stationary.

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For additional details about how and why the agency selected the crossover speed of 30 km/h refer to section III.D. in this document.

The agency proposed to require HVs and EVs to make a minimum amount of sound in each of eight different one-third octave bands, under each of several test conditions. The agency developed the minimum sound levels for each one-third octave band using a detection model that estimated the distance at which a pedestrian would be able hear a given sound in the presence of a given ambient sound profile. In the NPRM, NHTSA proposed to require eight one-third octave bands with the perspective that required sounds should be detectable in a wide variety of ambients, including ambients that had different acoustic characteristics from the ambient that we used with our detection model. The NPRM also required that sound produced by EVs and HVs be recognizable to pedestrians as motor vehicle sounds by containing low frequency tones and broadband content because these are characteristics commonly associated with sounds produced by internal combustion engines.

The compliance test procedure specified in the NPRM was to be performed outdoors and was based in part on SAE J2889-1 SEPT 2011. The compliance test procedure contained tests for stationary, reverse, and pass-by tests conducted at 10 km/h, 20 km/h, and 30 km/h. We explained in the NPRM that NHTSA believed that outdoor pass-by testing would be preferable to indoor testing in hemi-anechoic chambers using dynamometers because outdoor testing is more representative of the real-world interactions between pedestrians and vehicles. We also expressed concern that specifications for indoor testing were not as developed and did not have the same level of objectivity, repeatability, and reproducibility as test specifications for outdoor testing.

The NPRM proposed a phase-in schedule consistent with the PSEA which would require “full compliance with the required motor vehicle safety standard for motor vehicles manufactured on or after September 1st of the calendar year that begins 3 years after the date on which the final rule is issued.” In the NPRM we stated that if the final rule was issued January 4, 2014, compliance would commence on September 1, 2015, which would mark the start of a three-year phase-in period. The NPRM proposed the following phase-in schedule:

• 30 percent of the subject vehicles produced on or after September 1 of the first year of the phase-in;

• 60 percent of the subject vehicles produced on or after September 1 of the second year of the phase-in;

• 90 percent of the subject vehicles produced on or after September 1 of the third year of the phase-in; and

• 100 percent of all vehicles produced on or after, by September 1 of

the year that begins three years after the date that the final rule is issued.

In the NPRM, we tentatively concluded that this phase-in schedule was reasonable for manufacturers and allowed the fastest implementation of the standard for pedestrian safety.

E. Summary of Comments to the NPRM

The agency received comments to the NPRM from a wide variety of commenters, including trade associations,

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vehicle manufacturers,

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advocacy groups,

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suppliers,

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academia,

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standards-development organizations,

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governments,

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and approximately 225 individuals.

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The trade associations representing manufacturers that submitted comments included the International Motorcycle Manufacturers Association (IMMA), the Truck and Engine Manufacturers Association (EMA), the Electric Drive Transportation Association (EDTA), the Motorcycle Industry Council (MIC) and the Organization Internationale DES Constructeurs d' Automobiles (OICA). The Alliance of Automobile Manufacturers and Global Automakers submitted a joint comment that is referenced here as the “Alliance/Global” comment.

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Such as Toyota Motor North America (Toyota), Volkswagen Group of America (Volkswagen), Porsche Cars North America (Porsche), Ford Motor Company (Ford), American Honda Motor Co. (Honda), Mercedes-Benz USA (Mercedes), General Motors Company (General Motors), Mitsubishi Motors R&D of America (Mitsubishi), Chrysler Group LLC (Chrysler), Navistar, Inc. (Navistar), Nissan North America, Inc. (Nissan) and BMW of North America, LLC (BMW).

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The public safety advocacy groups submitting comments to the proposal included National Federal of the Blind (NFB), National Council of State Agencies of the Blind, the Advocates for Highway Safety (the Advocates), Noise Pollution Clearinghouse, the Insurance Institute for Highway Safety (IIHS), Safe Kids Worldwide, the World Blind Union, and American Council of the Blind (ACB).

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Such as Denso International America, Inc. (Denso) and Hear for Yourself, LLC.

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Such as the Mercatus Center at George Mason University, Western Michigan University (Western Michigan), and Accessible Designs for the Blind (ADB).

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SAE International.

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The European Commission Enterprise and Industry Directorate-General (DG Enterprise), and the Disability and Communication Access Board of Hawaii.

The primary issues raised by the advocacy groups and manufacturers concerned our proposal to require sound while hybrid and electric vehicles are stationary but active and our proposal to establish minimum sound requirements up to a speed of 30 km/h. Manufacturers and trade association groups argued that a sound at stationary is not required for safety. These commenters stated NHTSA should instead mandate a commencing motion sound that activated when the driver of an HV/EV removed her foot from the brake pedal. Manufacturers and trade associations also commented that the agency should only establish minimum sound requirements up to 20 km/h, arguing that above 20 km/h tire and wind noises are the dominant contributors to the sound produced by moving vehicles, and provide enough sound for pedestrians to safely detect hybrid and electric vehicles.

NFB and ACB supported the agency's proposal to require that hybrid and electric vehicles produce sound in the stationary but active operating condition, because it would help blind and visually-impaired pedestrians be aware of nearby vehicles and avoid collisions. NFB, ACB, and Advocates also supported the agency's proposal to establish minimum sound requirements for speeds up to 30 km/h, stating that they believe that the agency's research supports establishing minimum sound requirements to those limits.

Manufacturers and groups that represent manufacturers were supportive of the concept of adding sound to EVs and HVs to enhance pedestrian detection but expressed concern that the minimum sound requirements proposed in the NPRM were more restrictive than necessary to accomplish this goal. They argued that sounds meeting the requirements proposed in the NPRM would be annoying to consumers and might negatively affect sales of hybrid and electric vehicles. Regarding the agency's proposed compliance test procedure, manufacturers and groups that represent manufacturers requested the option to conduct compliance testing in indoor hemi-anechoic chambers using dynamometers, arguing that that is a more accurate and consistent method of testing because it is a more controlled environment that minimizes the kind of ambient variations that are expected in outdoor environments. They also raised issues regarding the agency's proposed method of measuring a vehicle's change in pitch as it increases or decreases speed, commenting that pitch shifting should be measured using a component-level test,

i.e.,

a bench test procedure, rather than testing the entire vehicle.

Manufacturers also disagreed with the agency's estimate of the cost of speaker systems needed to produce sounds capable of complying with the requirements in the NPRM, stating that speakers capable of producing the low frequency content specified in the proposed minimum sound requirements were more expensive than the agency estimated.

Organizations that represent manufacturers of motorcycles and heavy-duty and medium-duty vehicles took issue with the agency's basis for applying the rule to the vehicles they manufacture, stating that the agency had not shown a safety need based on crash data. They stated that the final rule should not apply to those vehicles because hybrid and electric motorcycles and heavy- and medium-duty trucks and buses do not pose an increased risk to pedestrians over ICE vehicles.

A number of individual commenters either expressed general support for the rule or general opposition to increasing the amount of sound produced by hybrid and electric vehicles. Several individuals also questioned why the agency was limiting the scope of the proposed rule to hybrid and electric vehicles. These commenters stated that the minimum sound requirements in the NPRM should apply to all vehicles including ICE vehicles that do not produce enough sound to be safely detected by pedestrians.

III. Final Rule and Response to Comments

A. Summary of the Final Rule

Today's final rule generally adopts the proposed standard but modifies the requirements in several ways. As proposed, we will require hybrid and electric vehicles to emit sound at minimum levels while the vehicle is stationary (although not necessarily at all times when the vehicle propulsion system is active); while the vehicle is in reverse; and while the vehicle is in forward motion up to 30 km/h. Today's final rule also adopts the agency's proposal to conduct compliance testing outdoors.

The agency is adopting numerous changes to the proposal in response to additional analysis conducted by the agency and in response to the comments on the proposal. The most significant change relates to the scope of the final rule. This final rule only applies to hybrid and electric passenger cars and LTVs with a GVWR of 4,536 kg (10,000) pounds or less and LSVs. This final rule does not apply to medium and heavy duty trucks and buses with a GVWR over 4,536 kg (10,000) pounds or to motorcycles. Based on a review of the available acoustic data regarding these vehicles and the comments, we have determined that we do not have enough information at this time to apply this final rule to medium and heavy duty vehicles and motorcycles.

We have determined the final rule should apply to LSVs, because unlike electric motorcycles and medium and heavy duty trucks and buses with a GVWR over 4,536 kg (10,000) pounds, we have acoustic data showing that LSVs are quiet. Therefore, we do not have any justification to exclude them

from the coverage of the final rule given the requirements of PSEA.

We have also made significant changes to the detectability specifications in the NPRM,

i.e.,

what sounds HV/EVs are permitted to make that the agency would consider compliant with the standard. After further consideration of the NPRM specifications, we are establishing new specifications in this final rule that provide greater flexibility for manufacturers in this respect, but that will still allow pedestrians to safely detect EVs and HVs. Specifically, whereas in the NPRM we proposed that HV/EVs would have to meet minimum acoustic requirements in eight separate one-third octave bands, in this final rule, the agency is providing two alternative acoustic specifications, either of which the agency would consider to be compliant, and both of which reduce the number of one-third octave bands for which there are minimum levels. Under the first compliance option, hybrid and electric vehicles would have to meet minimum acoustic requirements in four one-third octave bands instead of eight. Under the second compliance option, hybrid and electric vehicles would have to meet minimum acoustic requirements in two one-third octave bands, plus meet an overall sound pressure minimum.

Under the four one-third octave band compliance option, the minimum sound requirements for each band would be slightly lower than the values proposed in the NPRM and the overall sound pressure of sounds meeting the four one-third octave band compliance option will be similar to those meeting the proposed requirements for eight bands in the NPRM. Under the two one-third octave band compliance option, the minimum sound requirements for each band are lower than those of the eight one-third octave band proposal in the NPRM for the low and mid frequency bands and higher than the minimum values in the NPRM for the high frequency one-third octave bands centered at 4000 Hz and 5000 Hz. Neither the four-band compliance option nor the two-band compliance option include requirements for tones or broadband content contained in the NPRM.

For both the two-band and four-band compliance options, the final rule expands the range of acceptable one-third octave bands to include those between 630 Hz and 1600 Hz (these bands were excluded in the NPRM). Reducing the number of required one-third octave bands while expanding the number of possible bands that manufacturers can use to meet the minimum requirements provides additional flexibility to manufacturers for designing pedestrian alert systems. Sounds meeting these new requirements will have a similar overall sound pressure level to those meeting the requirements in the NPRM. These changes preserve the agency's goal of establishing requirements that will lead to pedestrian alert sounds that are detectable in ambient sound environments with different spectral shapes. The detectability specifications are discussed further in Section III.E of this final rule.

The agency originally proposed to require “pitch shifting,” meaning that as HV/EVs increased or decreased in speed (from stationary up to the cutoff of 30 km/h), the frequency of the sound produced by the HV/EV had to vary up or down with speed by one percent per km/h. After further consideration, we have concluded that the proposed pitch shifting compliance test is likely to have repeatability issues and may involve subjective assessments in compliance evaluations. For those reasons, and also in response to information raised in manufacturers' comments, the agency has decided instead to require simply that the vehicle-emitted sound increase and decrease in volume by a specified amount as the vehicle's speed increases and decreases. The agency believes this revised requirement, like the proposed pitch shifting requirement, will appropriately convey to pedestrians when a vehicle is accelerating or decelerating. This approach also has a testing advantage in that changes in vehicle speed and corresponding changes in vehicle-produced sound can be determined using the same data collected during the stationary and constant-speed pass-by tests. This issue is discussed further in Section III.G of this final rule.

The agency also proposed to require the pedestrian alert sound to contain a low frequency tone under 400 Hz to aid recognizability by pedestrians, stating that this would make the required alert sounds more similar to ICE vehicle sounds which typically include low frequencies. Based on additional analysis indicating that low-frequency tones are not essential for vehicle-emitted sounds to be recognized as motor vehicles in operation, and manufacturer comments arguing that low-frequency tones would be intrusive to vehicle occupants and expensive to reproduce, we have decided against including the proposed requirement in the final rule. Section III.F discusses this issue in more detail.

Also to aid recognizability, we originally proposed to require that the vehicle-emitted sounds contain broadband sound between 160 Hz and 5000 Hz. This means sound across a wide range of frequencies, and reflects the fact that ICE vehicles produce broadband sound when operating at low speed. We agree with commenters that this requirement is not critical for sound recognition because we believe that pedestrians will use other sound cues that provide more information in order to recognize sounds meeting the requirements of the final rule as vehicle-emitted sounds. In addition to the revised requirement that the alert sound level must increase as a vehicle increases speed, we believe that pedestrians would use other cues to recognize EVs and HVs such as the location of the sound source and the frequency and level changes caused by the motion of the sound, so tones and broadband content are not essential for these vehicles to be recognizable. This issue is discussed more in Section III.F of this final rule.

With regard to test procedures, the final rule also makes a number of changes from the proposal. We have modified the procedure for determining whether the sound produced by two hybrid or electric vehicles of the same make, model, and model year is the same. After further analysis, we have determined that requiring the sound produced by two hybrid or electric vehicles of the same make, model, and model year to be within three dB(A) for every one-third octave band between 315 Hz and 5000 Hz would not guarantee that the sound produced by the two vehicles would be the same. We have instead decided to ensure that EVs and HVs of the same make, model, and model year produce the same sound by requiring that all vehicles of the same make, model, and model year use the same alert system hardware and software, including specific items such as the same digital sound file where applicable, to produce sound used to meet the minimum sound requirements in today's final rule. We have also made numerous other changes to the proposed test procedures in response to comments.

While we have retained the requirement that EVs and HVs must generate an alert when stationary, the final rule requires an alert only when a vehicle's transmission gear selector is not in the “Park” position. We have changed the test procedure accordingly, and we will test this condition with the vehicle's gear selector in “Drive” or any forward gear. We believe that this modification to the stationary requirement will provide pedestrians with a way to detect those vehicles that

pose the greatest risk to them (

i.e.,

those vehicles that could begin moving at any moment) while ensuring that EVs and HVs do not produce unwanted sound in situations in which they do not pose a threat to pedestrians, such as when they are parked. The final rule requirements and procedures also address vehicles with manual transmission. Test procedures are discussed in more detail in Sections III.J and III.K of this preamble.

With regard to the phase-in schedule for the standard, we have simplified the proposed phase-in schedule by shortening it to include a single year of phase-in, rather than the three-year phase-in that the agency proposed in the NPRM. This simplification provides somewhat greater lead-time and responds to vehicle manufacturers' comments that the proposed phase-in was unnecessarily complex. Half of each manufacturer's HV and EV production must comply with this final rule by September 1, 2018, and 100 percent of each manufacturer's HV and EV production must comply with this final rule by September 1, 2019. The phase-in does not apply to multi-stage and small volume manufacturers: 100 percent of their HV and EV production must comply with this final rule by September 1, 2019.

B. Applicability of the Standard

Definition of a Hybrid Vehicle

The PSEA defines “hybrid vehicle” as “a motor vehicle which has more than one means of propulsion.” As discussed in the NPRM, we concluded that the definition in the PSEA requires the agency to apply the standard only to hybrid vehicles that are capable of propulsion without the vehicle's ICE operating, because if the ICE is always running when these vehicles are operating, then the fact that these vehicles may not provide sufficient sound for pedestrians to detect them cannot be attributed to the type of propulsion. Under the agency's interpretation of the definition of “hybrid vehicle” in the PSEA, more than one means of propulsion therefore means more than one

independent

means of propulsion. This definition of “hybrid vehicle” would exclude from the applicability of the proposed standard those vehicles that are equipped with an electric motor that runs only in tandem with the vehicle's ICE to provide additional motive power, for example a vehicle that cannot operate in a purely electric drive mode.

The NPRM also stated that the PSEA did not limit the definition of “hybrid vehicle” to hybrid-electric vehicles, so the proposed rule would apply to any vehicle with multiple independent means of propulsion. However, the definitions section of the NPRM regulatory text did not include a specific definition of “hybrid vehicle.”

Alliance/Global and OICA disagreed with the agency's proposal that the standard should apply to any vehicle with multiple independent means of propulsion, and argued that it should apply only to those vehicles that have an electric motor as the additional means of independent propulsion. Alliance/Global and OICA stated they do not believe that vehicles with non-electric hybrid powertrains should be subject to the requirements of the final rule, because the agency has not demonstrated that those vehicles are quiet. Alliance/Global and OICA also stated that the final rule should include a definition of “hybrid vehicle” in paragraph S4 of the regulatory text.

Agency Response to Comments

We agree that a definition of “hybrid vehicle” should be included in the rule and have added one. The definition appears in Section S4 of the regulatory text, and is based on the definition for a hybrid vehicle that was presented in the “Application” section of the NPRM preamble, where we stated that a hybrid vehicle is “a motor vehicle that has more than one means of propulsion for which the vehicle's propulsion system can propel the vehicle in the normal travel mode in at least one forward drive gear or reverse without the internal combustion engine operating.”

In response to the industry request to limit the scope of the rule to only HVs with an electric motor as the additional means of propulsion, we are aware that some alternative hybrid vehicles may use something other than an electric drive system in conjunction with an ICE, for example, a hybrid that uses hydraulic or flywheel energy storage in place of electric motor and batteries, although we currently are not aware of hybrid vehicles other than hybrid-electrics that are for sale in the U.S.

Regardless of whether such vehicles are currently available for sale, however, we continue to believe that any hybrid operating under an independent, non-ICE means of propulsion should be required to meet the minimum sound requirements of this standard because we have no evidence that they may

not

be capable of operating as quietly as electric hybrids. From a safety perspective, the agency is concerned with all hybrids that might operate quietly, regardless of the power source for their non-ICE propulsion, and commenters provided no information about whether hybrid vehicles other than hybrid-electrics would be any less quiet than hybrid-electric vehicles when not equipped with pedestrian alert systems. As for hybrids other than electric ones, if the vehicle produces sound levels in excess of those required by this final rule then no additional alert would be required; if not, an additional alert would be required.

Vehicles With a GVWR Over 10,000 lbs.

In the NPRM, we stated that the PSEA requires the agency to apply the requirements of the standard to all hybrid and electric motor vehicles which includes cars, multipurpose passenger vehicles, trucks, buses, low-speed vehicles and motorcycles.

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However, we acknowledged that ICE vehicles with a gross vehicle weight rating (GVWR) over 10,000 pounds (lbs.) have a lower rate of collisions involving pedestrians than light ICE vehicles,

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and we stated that we were not able to calculate a separate incidence rate for collisions between pedestrians and hybrid and electric vehicles with a GWVR over 10,000 lbs. because the number of those vehicles in the on-road vehicle fleet was extremely limited. Because we were not able to calculate a separate incidence rate for collisions involving pedestrians and hybrid and electric heavy vehicles, we did not calculate the benefits of applying the rule to them in the NPRM. We stated in the NPRM that we believe that as the number of these vehicles in the fleet increases, the difference in pedestrian collision rate between heavy HV/EVs and heavy ICE vehicles would be similar to the difference in pedestrian collision rate between light HV/EVs and light ICE vehicles.

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The PSEA specifically excludes trailers from the scope of the required rulemaking.

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For the purposes of this document we refer to all motor vehicles with a GVWR over 10,000 lbs. as “heavy-duty vehicles.”

The agency also recognized at the time of the NPRM that we had very limited data about the sound levels produced by hybrid and electric heavy vehicles. We also acknowledged that there are a limited number of test pads having pavements that meet ISO 10844,

Acoustics—Specification of test tracks for measuring noise emitted by road vehicles and their tires,

that can accommodate the extra weight of heavy vehicles.

Manufacturers and organizations that represent manufacturers of heavy-duty vehicles stated that NHTSA should not apply the final rule to heavy-duty vehicles because the agency had not established that these vehicles are quiet, could not demonstrate a safety need to

merit applying the requirements of the proposal to these vehicles, and had not developed appropriate requirements and compliance tests for these vehicles. Safety advocacy organizations and organizations that represent individuals who are blind and visually-impaired, in contrast, stated that NHTSA should apply the requirements of the final rule to heavy-duty vehicles because these vehicles would pose an increased risk of collision with pedestrians if they were quiet.

EDTA stated in its comments that NHTSA should defer application of minimum sound requirements in the final rule to heavy-duty vehicles, motorcycles and low-speed vehicles until the agency establishes a more complete record showing the need for these vehicles to meet those requirements. EDTA further stated that if the agency found that the requirements in the final rule should apply to heavy-duty vehicles, motorcycles and low-speed vehicles, the agency should develop audibility specifications that reflect the technologies, duty cycles and uses, and sound profiles specific to these types of vehicles.

EMA and Navistar stated that NHTSA should exclude hybrid and electric vehicles with a GVWR over 10,000 lb. from the scope of this rulemaking until the agency identifies a potential unreasonable risk to safety caused by the quiet nature of these vehicles, develops acoustic requirements specifically for these vehicles, and develops appropriate compliance test procedures.

EMA stated that, in addition to the incidence rate of collisions between pedestrians and heavy vehicles, NHTSA also should consider the exposure level of pedestrians to being struck by heavy-duty vehicles. EMA stated that certain heavy vehicles such as truck tractors do not typically operate in environments where pedestrians are present, so their risk of collision with pedestrians is much lower than the risk for passenger cars. In addition to having lower rates of exposure to pedestrians, heavy-duty vehicles make up a small fraction of the on-road vehicle fleet when compared to light vehicles. EMA suggested that the risk of a pedestrian being struck by a heavy-duty vehicle is much lower than the risk of a pedestrian being struck by a light vehicle when the percentage of heavy vehicles in the on-road fleet and their exposure to pedestrians are considered. EMA further suggested that lower rate of collisions with pedestrians and the low exposure show that NHTSA should not apply a single countermeasure with the same test procedures to all hybrid and electric vehicles.

EMA stated that NHTSA does not have any acoustic data that shows that heavy-duty hybrid and electric vehicles are quieter than heavy ICE vehicles and pose a safety risk to blind and other pedestrians. EMA stated that the NPRM did not contain any data comparing the sound produced by heavy-duty ICE vehicles to heavy-duty hybrid and electric vehicles. EMA stated that without acoustic data on heavy vehicles, NHTSA is unable to know what the crossover speeds are for heavy-duty vehicles or whether heavy-duty vehicles produce sufficient sound that they do not need to be equipped with a sound generation device. In addition, EMA stated that the crossover speed developed for light vehicles might be inappropriate for heavy-duty vehicles. Because these vehicles have larger tires than light vehicles and often have more tires and have a less aerodynamic body design they produce more sound than light vehicles under the same operating conditions.

EMA stated in its comments that applying the requirements in the NPRM to heavy-duty vehicles would violate the PSEA because NHTSA has not determined a separate crossover speed for heavy vehicles. EMA stated that to comply with the PSEA NHTSA must determine the crossover speed for each type of heavy-vehicle to which the final rule would apply. EMA stated further that applying the NPRM to heavy-duty vehicles violates the Vehicle Safety Act because the NPRM did not assess whether a different standard was needed for heavy vehicles.

Advocates commented that NHTSA should apply the final rule to hybrid and electric heavy vehicles. Advocates suggested that as advances in alternative energy increase, there will be a greater number of these types of vehicles. Advocates stated “the agency should consider its findings that pedestrians and pedalcyclists, especially the visually-impaired, utilize the different sound of heavy vehicles when compared with light vehicles to modify their estimation of when it is safe to undertake a movement, like crossing a road, which may vary with vehicular traffic.”

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For that reason, Advocates suggested NHTSA should consider establishing different acoustic requirements to ensure that pedestrians and others can accurately identify and distinguish between heavy and light EVs and HVs. Advocates further stated that NHTSA should standardize the backing sound across all heavy vehicles so that pedestrians and bicyclists can differentiate backing heavy vehicles from other vehicles.

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Document No. NHTSA-2011-0148-0270.

ACB and NFB stated that the final rule should apply to heavy-duty hybrid and electric vehicles because these vehicles pose the same safety risks to pedestrians as light vehicles, and the number of these vehicles in the fleet will likely increase in the future.

Western Michigan University stated that if the intent of the rule is to address potential hazards to the travel of blind pedestrians, then potentially quiet hybrid and electric heavy-duty vehicles should be required to meet the minimum sound requirements in the final rule. WMU stated that it was not aware of research on the audibility of hybrid and electric buses or light rail vehicles but that it seemed better to err on the side of caution and include heavy-duty hybrid and electric vehicles in the coverage of the final rule.

Agency Response to Comments

Despite what was proposed in the NPRM, we have decided not to apply the requirements of this final rule to heavy-duty hybrid and electric vehicles. We reached this decision because we do not believe that we currently have enough information to determine whether the acoustic requirements or the crossover speed in this final rule are appropriate for heavy-duty hybrid and electric vehicles. Therefore, we plan to conduct further research on sound emitted by heavy-duty hybrid and electric vehicles before issuing a new NPRM proposing acoustic requirements for these vehicles.

As described in Section II.C, after NHTSA issued the NPRM, we conducted testing to examine the sound levels produced by heavy-duty electric and hybrid vehicles. The agency tested the Navistar eStar Electric Heavy Vehicle following the procedures in SAE J2889-1, MAY 2012, using an ISO asphalt pad meeting the specifications of International Standards Organization (ISO) 10844 “Acoustics—Specification of test tracks for measuring noise emitted by road vehicles and their tyres.”

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The agency compared the acoustic recordings of the Navistar eStar to the four-band acoustic specifications in today's final rule. The eStar met or exceeded a number of minimum one-third octave levels at the 10, 20, and 30 km/h pass-by test conditions. According to the agency's detection model, given a background noise level at the standard ambient, a vehicle is detectable if it

meets or exceeds the minimum levels for detection in at least one of thirteen one-third octave bands. So the eStar without any noise enhancements would be expected to be detectable at least in the standard ambient at the tested pass-by speeds. For the stationary test, the eStar had acoustic content that met or exceeded the minimum values in three non-adjacent one-third octave bands. So in many ambient environments, in addition to the standard ambient, the eStar without any enhancements would be expected to be detectable at stationary.

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Hastings, et al., (2014) Acoustic Data for Hybrid and Electric Heavy-duty Vehicles and Electric Motorcycles.

The agency also conducted screening tests in the field of the sound levels of a selection of other heavy-duty EVs and HVs using a simplified procedure. For these screening tests, NHTSA measured four different electric or hybrid-electric transit buses, as described in the agency's report “Acoustic Data for Hybrid and Electric Heavy-duty Vehicles and Electric Motorcycles”

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which provides details of those measurements.

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These screening tests were basic evaluations of the sound characteristics of these vehicles, and they were conducted at facilities belonging to transit agencies or at other suitable locations. Therefore they did not utilize an asphalt pad meeting the specifications in ISO 10844. Additionally, for these screening tests the agency used hand-held (or tripod-mounted) sound level meters rather than the requisite microphone array specified in SAE J2889-1.

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Hastings, et al., (2014) Acoustic Data for Hybrid and Electric Heavy-duty Vehicles and Electric Motorcycles.

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Using the informal measurement procedures to capture these recordings allowed the agency to gather data on heavy-duty hybrid and electric vehicles without the difficulty and expense of transporting these vehicles to a location where they could tested on a sound pad meeting the specifications of International Standards Organization (ISO) 10844 “

Acoustics—Specification of test tracks for measuring noise emitted by road vehicles and their tyres”

as required by SAE J2889-1.

In conducting these screening measurements, the agency only recorded results for the eight one-third octave bands for which we proposed requirements in the NPRM. The agency compared the measurements to the revised minimum detectability thresholds based on our human factors research.

Of the three vehicles the agency evaluated in the stationary condition, all had sound content in several bands, and all would have been detectable in some ambient conditions according to the agency's detection model. At the 10 km/h pass-by, all of the vehicles tested would be expected to be detectable according to the detection model. At the 20 km/h pass-by, three of the vehicles would be expected to be detectable according to the detection model, and two would have met the requirements of the final rule.

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The agency only tested one of the four vehicles at 30 km/h.

This heavy vehicle screening data showed that some hybrid and electric heavy-duty vehicles may already make sufficient sound in some operating conditions to be detected by pedestrians according to the agency's model. Because the data the agency collected during screening testing is limited in scope and was not obtained on an ISO 10844 compliant surface, the agency needs to conduct further evaluation in this area before we can draw conclusions regarding the sound levels produced by these vehicles.

Furthermore, the agency does not have any data on the crossover speed of heavy vehicles. Given that heavy vehicles have very different tires and wind noise characteristics than light vehicles, and these factors heavily influence crossover speed, it is possible that the light vehicle crossover speed is inappropriate for heavy vehicles. The agency anticipates conducting further research and evaluation to make these determinations and, if it proves necessary, to develop separate acoustic requirements for these vehicles.

Regarding EMA and Advocates comments that the agency should develop a separate acoustic specification for heavy-duty vehicles, for the reasons discussed above NHTSA agrees and plans to conduct further evaluations on this issue.

Given that NHTSA has not yet established that heavy hybrid and electric vehicles are too quiet to be detected without a pedestrian alert system, and the agency has not determined that the same acoustic requirements and crossover speed for light vehicles in today's final rule are appropriate for heavy vehicles, we are excluding both those categories from the applicability section of today's final rule, and we anticipate conducting a separate rulemaking effort to address the potential need for pedestrian alert systems on those vehicles.

Electric Motorcycles

In the NPRM, we stated that we had tentatively concluded that the proposed rule should apply to electric motorcycles, because Congress defined “electric vehicle” broadly in the PSEA and did not exclude motorcycles from the definition. We acknowledged that the agency was not able to determine whether the incidence rate of collisions between pedestrians and electric motorcycles is different than the incidence rate of collisions between pedestrians and motorcycles with ICEs, but stated that we expected that the difference in pedestrian collision rates between electric motorcycles and their traditional ICE counterparts would be similar to the difference in pedestrian collision rates between light HVs and light ICE vehicles should the number of electric motorcycles in the fleet match the current market penetration of light HVs and EVs. Additionally, while we did not have data on the extent to which electric motorcycles are quieter than ICE motorcycles of the same type, we also noted that neither did we have information indicating whether electric motorcycles produced sound levels sufficient to allow pedestrians to detect these vehicles in time to avoid collisions. The NPRM did, however, cite crash statistics contained in BMW's comments on the NOI regarding incidents of motorcycle collisions with pedestrians. BMW cited data from NHTSA's General Estimates System (GES) for the period between 2005 and 2009 shows that 1.07 percent of the pedestrians injured in motor vehicle crashes were injured in crashes involving motorcycles to illustrate the low rates of crashes between motorcycles and pedestrians.

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BMW's comments on the NOI.

Available at

http://www.regulations.gov

, Docket No. NHTSA-2011-0100-0020. Referring to the data cited, BMW argued in its NOI comments that based on the number of crashes between motorcycles and pedestrians and the percentage of all pedestrian crashes involving motorcycles, there is no safety need for minimum sound requirements for electric motorcycles.

We also stated in the NPRM that the proposal was technology-neutral and that it would be possible for electric motorcycles to meet the requirements in the NPRM without the use of a speaker system if they already produced sufficient sound to meet the performance requirements. We sought comment on whether the minimum sound requirements should be applied to electric motorcycles.

The comments that the agency received in response to the NPRM from organizations that represent motorcycle manufacturers for the most part reiterated the concerns expressed by MIC and BMW in response to the NOI. BMW and MIC stated in their comments to the NOI that, because of the unique attributes of motorcycles, there is no safety need for NHTSA to establish minimum sound levels for electric motorcycles. MIC reiterated this point in their NPRM comments. According to

MIC and BMW, motorcycle riders are able to better see and avoid pedestrians than automobile drivers because their view is unobstructed by pillars and sun visors and they are more alert because they themselves are vulnerable road users. BMW and MIC maintained that because motorcycles are unstable at low speeds, riders are required to maintain a high level of alertness, which minimizes the likelihood of collisions with pedestrians during low speed maneuvers.

Also in their NOI comments, both BMW and MIC stated that adding a speaker system to a motorcycle could involve technical challenges not present for other vehicles because there is less space on the motorcycle to install the speaker and the weight of the speaker would have a greater impact on the vehicle's range. MIC and BMW also suggested that electric motorcycles should not be subject to the minimum sound level requirements in this proposal because electric motorcycles are not quiet.

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MIC submitted measurements of overall sound pressure level of two electric vehicle models recorded at 8 km/h (5 mph) and 16 km/h (10 mph) in its comments to the NOI. MIC did not provide any measurements of overall sound pressure level for ICE motorcycles as a comparison.

Available at,

www.regulations.gov

, Docket No. NHTSA-2011-0100-0028.

MIC commented in response to the NPRM that motorcycles should be exempt from meeting the minimum sound requirements in the final rule because motorcycles, both electric and ICE, pose less of a risk to pedestrians than other vehicles, citing statistics that the collision rate between motorcycles and pedestrians is 0.27 percent compared with 0.76 percent for other vehicles under conditions most likely to pose a threat to pedestrians (backing up, turning, entering or leaving parking spaces, starting, or slowing).

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Docket No. NHTSA-2011-0148-0268.

MIC argued that NHTSA's assumption that electric motorcycles will show a similar increase in rate of pedestrian collisions as four-wheeled “HEVs” (MIC's term for hybrid and electric vehicles, collectively) is invalid because four-wheeled HEVs in fact do not pose a greater threat to pedestrians than ICE vehicles. MIC stated that the higher incidence of collisions between pedestrians and HEVs does not mean that HEVs collide with pedestrians at a higher frequency, arguing that NHTSA's comparison of incidence rates of pedestrian collisions between ICEs and HEVs to determine the overall frequency of pedestrian crashes between each group of vehicles is only valid if both classes of vehicles have similar overall crash rates. However, according to MIC, that is not the case, and the difference in overall crash rates is supported by FARS data which indicate that the overall crash rate for HEVs is only half of the overall crash rate for ICEs. MIC stated that the higher incidence rate of HEV-pedestrian collisions is likely to be artificial and driven by demographic factors other than sound, mainly that HEV drivers actually tend to be safer drivers on average, which makes their overall crash rate lower and which inflates their rate of pedestrian crashes as a percentage of all crashes. MIC pointed out that motorcycle pedestrian crash frequency is actually no higher than for ICEs. MIC stated that crash rate differences due to demographic factors are not uncommon and are, for example, what explain large differences in fatality rates between different types of motorcycles (

e.g.,

touring bikes compared to sport bikes). Overall, MIC concluded that, because motorcycles have a lower overall crash rate than four-wheeled vehicles, the risk they pose to pedestrians is actually lower than the incidence rate of motorcycle-pedestrian crashes might indicate.

MIC also argued that it is logical that motorcycles should have a lower rate of collisions with pedestrians because motorcycles require two hands to operate so there is a lower chance of the operator being distracted, which should decrease the risk to pedestrians.

MIC stated that, in addition to having a low rate of crashes involving pedestrians, electric motorcycles are not quiet. MIC referenced a report submitted in response to the NPRM by Brammo, Inc., a manufacturer of electric motorcycles, that MIC believes shows that by design, electric motorcycles are not silent vehicles when moving.

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MIC stated that unlike EV automobiles, the engine and drivetrain are open and exposed to the surrounding environment, and will produce sound levels that exceed the sound level minimums proposed by NHTSA. MIC stated that two motorcycles tested by Brammo, the Empulse and the Enertia Plus, produced sound levels that were 8 to 18 dB(A) higher than the minimum requirements in the NPRM.

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The report submitted by Brammo, Inc. is available through

www.regulations.gov,

Docket No. NHTSA-2011-0148-0268.

MIC also stated that the NPRM did not take into account that motorcycles do not have a reverse gear and therefore do not collide with pedestrians while backing.

MIC stated that NHTSA should not establish minimum sound requirements for electric motorcycles until there is evidence that these vehicles pose a safety risk to pedestrians. MIC stated that if NHTSA does decide to establish minimum sound requirements for motorcycles, it should extend the exemption for small-volume manufacturers indefinitely.

IMMA suggested that electric motorcycles do not introduce a new threat to blind and visually impaired pedestrians because blind and visually impaired pedestrians already are exposed to pedalcyclists on both the road and on sidewalks (and bicycles would not be any louder than electric motorcycles). Operators of electric motorcycles, like pedalcyclists, have the advantage of greater awareness of nearby pedestrians and greater ability to avoid them.

IMMA stated that limited data exists on crashes between motorcycles and pedestrians and pedalcyclists but that there are a significant number of incidences of crashes involving motorcycles and four-wheeled vehicles, which it argued showed the high vulnerability of motorcycle riders and their inherent alertness to other road users including pedestrians. They also commented that motorcycles by design provide the operator with better vision of the surrounding environment which increases awareness of nearby pedestrians and pedalcyclists.

IMMA commented that studies have shown that pedestrians are at greater risk of being struck by HVs while the vehicle is operating in reverse, but this is not a concern for motorcycles because the vast majority of motorcycles do not have a reverse gear and those that do cannot move quickly in reverse.

IMMA stated that preliminary data shows that electric motorcycles are not quiet and suggested that this data, coupled with the fact the electric motorcycles do not pose an increased risk to pedestrians, shows that electric motorcycles should not be subject to the minimum sound requirements in the final rule.

DG Enterprise stated that the detectability parameters determined for EVs and HEVs in the NPRM may require the installation of an alert sound system on other quiet vehicles such as electric motorcycles and mopeds as well as electrically assisted bicycles. DG Enterprise inquired whether NHTSA plans to mandate the installation of and “AVAS” (Acoustic Vehicle Alerting Systems) in all these vehicle categories.

Western Michigan stated that all quiet vehicles traveling at the slow speeds covered by the NPRM

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