Federal Motor Vehicle Safety Standards; Stability and Control of Medium and Heavy Vehicles During Braking

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 92-29; Notice 10]

RIN 2127-AF96

Federal Motor Vehicle Safety Standards; Stability and Control of

Medium and Heavy Vehicles During Braking

AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION: Final rule, petitions for reconsideration.

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SUMMARY: This document responds to petitions for reconsideration of

final rules that amended FMVSS No. 105, Hydraulic Brake Systems, and

FMVSS No. 121, Air Brake Systems, to require medium and heavy vehicles

to be equipped with an antilock brake system (ABS). In response to the

petitions, this document requires continuous power for trailer ABS

systems, in place of the dedicated power and separate ground previously

required, and delays the implementation date for the in-cab trailer

malfunction indicator by four years. It also extends by three years the

period in which exterior ABS failure indicators are required on

trailers.

DATES: Effective Dates: The amendments to 49 CFR 571.121 are effective

March 1, 1997.

Compliance Dates: Compliance with the amendments to paragraphs

S5.1.6.2(b) and S5.2.3.2 of 49 CFR 571.121 will be required on and

after March 1, 2001. Compliance with the amendments to paragraph

S5.1.6.3 for truck tractors will be required on and after March 1, 1997

and for single unit vehicles will be required on and after March 1,

1998. Compliance with the amendments to paragraph S5.2.3.2 will be

required on and after March 1, 2001. Compliance with the amendments to

S5.2.3.3 will be required on and after March 1, 1998.

Petitions for Reconsideration: Any petitions for reconsideration of

this rule must be received by NHTSA no later than April 1, 1996.

ADDRESSES: Petitions for reconsideration of this rule should refer to

the above referenced docket numbers and should be submitted to:

Administrator, National Highway Traffic Safety Administration, 400

Seventh Street, SW., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

For non-legal issues: Mr. Robert M. Clarke, Office of Crash

Avoidance, National Highway Traffic Safety Administration, 400 Seventh

Street, SW., Washington, DC 20590 (202) 366-5278.

For legal issues: Mr. Marvin L. Shaw, NCC-20, Rulemaking Division,

Office of Chief Counsel, National Highway Traffic Safety

Administration, 400 Seventh Street, SW., Washington, DC 20590 (202)

366-2992.

SUPPLEMENTARY INFORMATION:

I. Background.

II. Petitions for Reconsideration.

III. NHTSA's Decision and Analysis of Issues.

A. Agency's Decision.

B. Trailer Powering.

1. Background and Previous NHTSA Rulings.

2. Petitions for Reconsideration of December 1995 Final Rule

3. Agency's Decision

C. In-Cab Trailer Malfunction Indicators

D. External Trailer Malfunction Indicators

I. Background

Section 4012 of the Motor Carrier Act of 1991, a part of the

Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, P.L.

102-240, directed the Secretary of Transportation to initiate

rulemaking concerning methods for improving braking performance of new

commercial motor vehicles, including truck tractors, trailers, and

their dollies. Congress specifically directed that such a rulemaking

examine antilock systems, means of improving brake compatibility, and

methods of ensuring effectiveness of brake timing. The Act required

that the rulemaking be consistent with the Motor Carrier Safety Act of

1984 (49 U.S.C. Sec. 31136) and be carried out pursuant to, and in

accordance with, the National Traffic and Motor Vehicle Safety Act of

1966 (now recodified as 49 U.S.C. Sec. 30101 et seq. (Safety Act)).

On March 10, 1995 (60 FR 13216, 60 FR 13297), NHTSA issued final

rules that required medium and heavy vehicles 1 to be equipped

with an antilock brake system (ABS) to improve their directional

stability and control during braking. The March 1995 final rules also

reinstated stopping distance requirements for air-braked heavy vehicles

and established stopping distance requirements for hydraulic-braked

heavy vehicles.

\1\ Hereinafter referred to as ``heavy vehicles''

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In addition to the ABS requirement, the ABS final rule required

truck

[[Page 5950]]

tractors and other towing vehicles to supply dedicated, full time

electrical power to a trailer ABS and required truck tractors and other

towing vehicles to be equipped with two separate in-cab lamps: one

indicating malfunctions in the towing vehicle ABS and the other

indicating malfunctions in the ABS on one or more towed trailers and/or

dollies. The rule also required all trailers, including dollies,

produced during an eight-year transition period, to be equipped with an

external malfunction indicator. In response to petitions for

reconsideration of these requirements, NHTSA published a final rule on

December 13, 1995 (60 FR 63965) affirming its decision to require these

features.

II. Petitions for Reconsideration of December 1995 Final Rule

NHTSA received petitions for reconsideration of the December 1995

amendments to the final rule from the American Trucking Associations

(ATA) which represents trucking fleets, the National Private Truck

Council (NPTC) which represents private trucking fleets, the Truck

Manufacturers Association (TMA) 2, the Truck Trailer Manufacturers

Association (TTMA) which represents trailer manufacturers, the Heavy

Duty Brake Manufacturers Council (HDBMC) 3 which represents heavy

duty brake component manufacturers, Midland-Grau, Kelsey-Hayes,

Rockwell WABCO, Vehicle Enhancement Systems (VES), AlliedSignal,

General Motors, Ford, and the Recreational Vehicle Industry Association

(RVIA).4

\2\ TMA member companies include Ford, Freightliner, General

Motors, Mack Trucks, Navistar International, PACCAR, and Volvo GM

Heavy Truck.

\3\ HDBMC member companies include Abex, AlliedSignal, Eaton,

Midland-Grau, Ferodo America, Haldex, Lucas, MGM Brakes, Motion

Control/Carlisle, Rockwell, Rockwell WABCO, and Spicer/Dana.

\4\ General Motors, Ford, Kelsey-Hayes, and the RVIA all address

amendments to FMVSS No. 105. In this notice, the agency is

responding to the issues relating to FMVSS No. 121. The agency will

address the petitions raising FMVSS No. 105 issues in a future

notice.

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As did the petitioners for reconsideration of the March 1995 final

rule, all petitioners for reconsideration of the December 1995 final

rule agreed with and supported NHTSA's decision and schedule requiring

all heavy vehicles to be equipped with ABS. ATA, TMA, and TTMA

reference what they refer to as the ATA/TMA/TTMA Industry Consensus

Position ABS Reconsideration petition,5 with which they have

stated their concurrence. The Industry Consensus Position states that

the agency should retain the current overall requirements and timing.

Similarly, TMA stated that its companies ``continue to support the

production, sale, and service of ABS within the specified time

frames.'' Nevertheless, the Industry Consensus Position and each of the

petitioners requested that the agency modify the requirements that

address trailer ABS power and the in-cab trailer malfunction indicator.

Specifically, the Industry Consensus Position is that the agency should

(1) delete the requirement for continuous, dedicated power 6 to

the trailer ABS and replace it with a requirement for continuous power

but no dedicated circuit (with backup power on the stoplamp circuit)

and delete the separate ABS ground requirement, and (2) delay the

effective date for an in-cab trailer warning light, but specify another

date that will accelerate the development of the specific means for

achieving the goal of having that warning light. The petitioners

supporting the Industry Consensus Position explained that the heavy

vehicle manufacturers and users are working together and are committed

to developing and deploying a satisfactory in-cab trailer warning light

within the extended time period requested.

\5\ Hereinafter referred to as ``Industry Consensus Position.''

\6\ The terms continuous power, dedicated power, and connector

are discussed in the next section.

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III. NHTSA's Decision and Analysis of Issues

As explained below, NHTSA has decided to amend FMVSS No. 121

consistent with the Industry Consensus Position and to replace the

requirement for dedicated power to trailer ABS with a requirement for

continuous power. Stoplamp power will continue to be required to

provide back-up power for the ABS. In addition, the agency has decided

to delete the requirement for a separate ABS ground and to allow a

common ground for ABS trailer powering. The agency has also decided to

delay the implemenation date for the in-cab trailer malfunction

indicator until March 1, 2001.

A. Trailer Powering

1. Background and Previous NHTSA Rulings

A trailer's antilock brake system may receive its electrical power

in one of the following ways: (1) intermittent power through the

stoplamp circuit, (2) continuous power through a circuit that is shared

and provides power to more than one electrical component or which is

used to transmit one or more signals, or (3) continuous, dedicated

power through a circuit whose sole function is to provide power to the

trailer ABS. With stoplamp powering, electrical power to the ABS is

only supplied when the brake pedal is applied and the stop lamp switch

is activated. As a result, the trailer ABS must share power with

stoplamp bulbs, which decreases the voltage available for powering the

trailer ABS. With continuous powering, electrical power to the trailer

ABS is present at all times, but other devices could be powered off the

same circuit and multiplexed 7 communication signals could be

carried on the circuit. With dedicated powering, electrical power to

the trailer ABS is present at all times, but no other device can be

powered off this circuit and communications signals cannot be carried

on the circuit.

\7\ Multiplexing is defined by the Society of Automotive

Engineers's (SAE's) Multiplex Subcommittee as ``The process of

combining several messages for transmission over the same signal

path.''

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Trailers do not typically have their own electrical power source.

Thus, an electrical connector is needed to provide electrical current

between a tractor and a trailer. At present, the most common electrical

connector used for this purpose in the United States is the SAE J560

plug/receptacle, which was developed in the 1950s and has been in

widespread use ever since. This connector has seven pins, providing

seven electrical paths: Pin one is used as a common ground for the

other six positive power pins; pin two is used to power clearance and

side marker lamps; pin three is used to power the left hand turn

signal; pin four is used to power the stoplamp; pin five is used to

power the right hand turn signal and hazard signal; pin six is used to

power the taillamp, marker lamps, and license plate lamps; and pin

seven is an auxiliary circuit that is not currently used in most

vehicle combinations. In the past, it has been common practice to power

trailer ABSs exclusively from pin 4, the stoplamp circuit. This

involves sharing power with the stoplamp bulbs which are only activated

when the brakes are applied.

In a fleet study 8 that NHTSA conducted to support the current

ABS rulemaking, the agency evaluated other ABS powering approaches,

including a single 13-pin connector, a separate six-pin connector, and

another separate connector known as the International

[[Page 5951]]

Standards Organization (``ISO'') connector. These other powering

approaches used dedicated electrical circuits, including separate,

fully dedicated positive and ground wires, to power the trailer ABS.

8 ``An In-Service Evaluation of the Performance,

Reliability, Maintainability, and Durability of Antilock Braking

Systems for Semitrailers,'' U.S. Department of Transportation/ NHTSA

Report No. DOT HS 808 059, October 1993

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In the March 1995 final rule, NHTSA decided to require dedicated

powering for trailer ABSs and to require that towing vehicles have a

corresponding separate circuit. (60 FR 13248-13250) The agency

explained that this requirement provides the most dependable source of

electrical power from the tractor to ensure the functioning of the

trailer's ABS.

In petitions for reconsideration of the March 1995 final rule,

American Automobile Manufacturers Association (AAMA), Midland-Grau, and

TTMA requested that NHTSA interpret the requirement for dedicated power

so that the ABS powering circuit need not be exclusively used for ABS.

AAMA and Midland-Grau requested the agency to allow other uses for this

circuit, such as powering interior van trailer lights and multiplex

signaling. ATA reasserted its concern that the requirement for a

separate circuit would be costly and would create operational problems,

because it would result in the use of a second tractor/trailer

electrical connector, which would be used only infrequently, until the

number of tractors and trailers with ABS increased, to the point where

a high percentage of vehicles in combination would be ABS equipped. ATA

stated a strong preference for a requirement that would allow the

continued use of the SAE J560 connector. In a September 6, 1995 letter,

ATA requested that the agency interpret the requirement for a separate

electrical circuit in such a way as to allow the continued use of the

SAE J560 connector.

In the December 1995 final rule responding to petitions for

reconsideration, NHTSA denied the petitioners' request to permit other

uses for the separate ABS circuit. Based on information available at

that time, NHTSA concluded that it was necessary for the ABS on towed

vehicles to receive full-time power through a dedicated circuit to

reduce the possibility of the ABS being inoperative due to lack of

power. The agency found no basis in the publicly available data on

which to alter its view that the dedicated circuit was necessary.

2. Petitions for Reconsideration of December 1995 Final Rule

In response to the December 1995 final rule, each petitioner

supported the Industry Consensus Position to permit continuous powering

to the trailer ABS. TMA stated that new information and industry

commitments support a decision to delete the dedicated powering

requirement and replace it with a continuous powering requirement. TMA,

Midland-Grau, ATA, AlliedSignal, HDBMC, and VES supplied data which

indicated that adequate levels of electrical power could be supplied to

trailer ABSs on non-dedicated circuits. Midland-Grau strongly supported

the continuous powering requirement with the stoplamp circuit as a back

up, provided that the ABS circuit could be used to power warning and

other monitoring systems. ATA supported the Industry Consensus

Position. That organization continues to believe that intermittent

powering through the stoplamp circuit provides adequate electrical

energy to power the trailer ABS, citing its analysis of additional data

and industry commitments to upgrade tractor electrical systems.

Nevertheless, ATA agreed to a requirement for continuous power instead

of stoplamp power, if the trailer ABS power supply circuit could be

used for other purposes.

All petitioners opposed the requirement for dedicated powering with

a separate ground. TMA, ATA, Midland-Grau, AlliedSignal, and HDBMC

stated that the separate ground requirement, which is an integral part

of dedicated powering, requires the use of diodes in the trailer ABS's

electrical control unit (ECU) which reduce the voltage available for

trailer ABS. They further stated that requiring two grounds could

create ``ground loop circuits,'' which may create unexpected voltage

differences between various electrical systems on vehicles. This may

result in electrical shorting and the possibility of electrical fires.

In support of their petitions, the petitioners provided new

information relating to the voltage requirements of the new generation

of ECUs, the amperage requirements of new modulators, and the voltage

losses associated with dedicated power circuits. The petitions also

stated that the petitioners are committed to meeting new voluntary

powering standards and to completing the development of a new

generation of electronic communications systems.

3. Agency's Decision

The agency's decisions are based on the new information provided in

the public record by the petitioners, as described above and discussed

more fully below. Based on this information, as well as recent studies

9 by the agency, NHTSA has decided to amend FMVSS No. 121

consistent with the Industry Consensus Position and to replace the

requirement for dedicated power to the trailer ABS with a requirement

for continuous power. Stoplamp power will continue to be required to

provide back-up power for the trailer ABS. In addition, the agency has

decided to delete the requirement for a separate ABS ground and to

allow a common ground for ABS trailer powering. The agency emphasizes

that continuous power rather than intermittent power through the

stoplamp circuit is needed as a primary powering source to ensure the

safe operation and reliability of trailer ABS and to provide the

capability to signal a continuous warning of a trailer ABS malfunction

to the cabs of towing units.

\9\ Winkler, C.B., Bogard, S.E., Bowen, M.A., Ganduri, S.M., and

Lindquist, D.J. ``An Operational Field Test of Long Combination

Vehicles Using ABS and C-Dollies'', University of Michigan

Transportation Research Institute Report No. 95-45-2, under USDOT/

NHTSA Contract No. DTNH22-92-D-07003, November 1995

Flick, M. A., ``NHTSA's Heavy Duty Vehicles Brake Research

Program Report Number 10--Evaluation of Trailer Antilock Braking

Systems Electrical Powering'', USDOT Report No. HS 808 249, March

1995.

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With respect to the safe operation of trailer ABS, an agency report

10 indicated that a problem can occur if power is interrupted to a

trailer ABS while it is cycling. Specifically, under lightly loaded or

empty trailer operating conditions on low coefficient of friction

surfaces, if a brake application that activates the ABS is fully

released and then fully applied again, the resulting interruption of

electrical current through the stoplamp circuit can cause the

reactivated ABS ECU to misinterpret the wheel speed signals it is

receiving. The ECU could interpret the signals as meaning that the

vehicle is stopped and thereupon allow the brakes to be fully applied.

This would result in locked trailer wheels. Notwithstanding the fact

that this type of brake application might occur infrequently in real-

world operating conditions, this possibility underlines the importance

of continuous powering as the primary method of powering trailer ABS,

and indicates that the stoplamp circuit should not be relied on as more

than a back-up to primary continuous powering. Data submitted by

Midland-Grau support the agency's position.

\10\ USDOT Report No. HS 808 249, March 1995.

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With respect to the reliability of trailer ABS, NHTSA's decisions

in earlier rulemakings focused on ensuring that the trailer ABS

received adequate voltage. In the March 1995 final rule,

[[Page 5952]]

the agency specified a requirement for a dedicated trailer ABS power

circuit as the best means to ensure adequate voltage levels (i.e., 9-10

volts) for trailer ABSs. The agency believed that a separate ground

wire was also needed to ensure sufficient capacity to provide a return

path for electrical current that would not be subject to excessive

voltage drops because the ground wire carried too much current. This

belief rested on data from the agency's fleet studies.

On the basis of this new information in the petitions for

reconsideration, NHTSA has determined that a continuous, but non-

dedicated, source of power and a shared ground will provide sufficient

power to the trailer ABS. The HDBMC petition stated that all current

versions of trailer ABSs function at levels as low as 8.5 volts, and

that ABS modulators have now been designed to draw a maximum of 3 amps.

The agency agrees with the HDBMC petition that the information

previously available indicating that trailer ABSs require 9-10 volts to

remain functional, and that ABS modulators draw 2-6 amps of current,

has been superceded. This information about the lower power needs of

new ABS systems indicates that a dedicated power source and a separate

ground wire are not necessary for ABS power.

The agency agrees with petitioners that the addition of a separate

ground wire would necessitate adding diodes to the trailer ECU powering

circuitry to prevent inadvertent ground loops that may result in

electrical short circuits or electrical fires. These added diodes would

result in a 0.7 volt decrease to the trailer ECU, an outcome

inconsistent with ensuring adequate power levels.

Based on the above considerations, NHTSA has decided to modify

sections 5.1.6.3 and 5.5.2 to require continuous power to trailer ABSs,

to permit the circuit to be shared with other devices and to allow

trailer ABS powering circuits to share a common ground with other

electrical powering circuits.

Powering electrical devices other than the trailer ABS from the ABS

power circuit has the potential to compromise the circuit's ability to

power the trailer ABS. A recently completed study on long combination-

unit vehicles (LCVs) 11 highlights the need to design all the

elements of tractor/trailer electrical system to ensure adequate

electrical power levels. Among other things, that study considered

whether sufficient voltage could be supplied to the rear trailers and

dollies of multiple trailer combinations (especially triple trailer

combinations) on the same circuit. The study found that even with

special wiring and well maintained connectors, it was necessary for the

electrical systems of tractors to supply 13.3 volts and for the ABS on

dollies and trailers to operate on no more than 9.0 volts in order to

ensure that sufficient electrical power could be supplied. Some of the

tractors in the test program were not able to consistently provide the

13.3 volts of electrical power through the stoplamp circuit, and some

of the ABSs needed more than 9.0 volts. In some cases, trailing unit

ABSs ceased functioning. Accordingly, a manufacturer can ensure

adequate powering for trailer ABSs by providing adequately sized

electrical wiring in both towing and towed units, by providing towing

units with heavy duty electrical charging systems, and by employing low

voltage demand lighting systems.

\11\ University of Michigan Transportation Research Institute

Report No. 95-45-2, under USDOT/NHTSA Contract No. DTNH22-92-D-

07003, November 1995

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The agency agrees with Midland-Grau's position that the only other

devices which should share this circuit are warning, monitoring, or

other signaling/communications devices. Additional uses that would not

likely pose problems are low power demand components or devices which

are powered when the vehicle is stopped or in reverse, conditions in

which the ABS would not be in use. However, the agency has decided not

to specify the devices that may share the use of the trailer ABS power

circuit. The agency is confident heavy vehicle manufacturers and users

recognize the need for appropriate restrictions and notes that industry

is working, through various SAE and other technical committees, to

establish performance standards for electrical systems that power

tractor and trailer ABS systems. These anticipated industry standards

are expected to include objective performance test procedures,

measurement criteria, and, in some cases, target performance levels.

Several of the petitioners specifically referenced SAE J2272, Truck

Tractor Power Output for Trailer ABS, and its TMC equivalent, RP137,

Antilock Electrical Supply for Tractors Through the SAE J560 Connector,

and indicated that they were committed to designing and using products

that meet these specifications. TTMA stated that it was developing a

comparable companion standard for trailer electrical systems.

NHTSA will monitor these efforts to develop consensus industry

standards and the commitment made by heavy vehicle manufacturers and

users to meet these voluntary standards. Efforts to develop consensus

on this topic have been under way since 1988, when WABCO submitted a

petition on trailer ABS powering schemes (53 FR 39751, October 12,

1988). The agency anticipates that this powering issue can be resolved

without further delays in the implementation schedule for the trailer

powering and in-cab indicator requirements.

After evaluating these voluntary standards, NHTSA may consider

further rulemaking to amend FMVSS No. 121 to require minimum voltage

levels at the tractor or to limit the use of the ABS power circuit if

such requirements appear necessary to ensure the adequacy of power to

the trailer ABS. Such a rulemaking action would be consistent with the

President's Regulatory Reinvention Initiative which encourages

regulatory agencies, when appropriate, to adopt voluntary standards

established and followed by the private sector.

B. Trailer Malfunction Indicators

FMVSS No. 101, Controls and Displays, sets forth requirements for

the location, identification, and illumination of motor vehicle

controls and displays. Table 2(a) of the standard lists various

telltales that are required in a motor vehicle to advise the driver of

the status of a variety of vehicle systems. For air brake equipped

trucks, these include telltales for brake system air pressure and for

ABS malfunction in the truck.

In the March 1995 final rule, NHTSA required lamps in the cab of

truck tractors to indicate any malfunction with the ABS of any towed

vehicles. (60 FR 13244, 13245) The agency also required trailers to

supply trailer ABS malfunction signals to the tractor. The agency

explained that it is essential that a driver be notified about an ABS

malfunction in the trailer, so that the problem can be corrected. The

agency cited results from the ABS fleet study which indicated that

drivers are more likely to observe a tractor in-cab indication of a

trailer ABS malfunction than they are a trailer-mounted lamp. The study

also noted that some trailer ABS malfunctions were present for a long

time, and not reported, because the drivers did not notice that the

trailer-mounted malfunction lamps were activated. Based on these

findings, the agency decided that it was necessary to require an in-cab

trailer ABS malfunction warning light to adequately ensure that such

malfunctions would be detected and corrected.

In response to the March 1995 final rule, ATA petitioned the agency

to delete the requirement for in-cab indication of trailer ABS

malfunctions.

[[Page 5953]]

It argued that such a requirement was unnecessary and would needlessly

complicate the electrical system of the tractor and the electrical

connector arrangement between tractors and trailers.

In the December 1995 final rule, NHTSA denied ATA's request to

delete the in-cab malfunction lamp for the trailer ABS. In explaining

that the in-cab trailer malfunction lamp is necessary, the agency

referenced a study that showed that an in-cab malfunction lamp is a

more effective means of making the driver aware of an ABS malfunction,

compared with an external malfunction lamp on the trailer.12 NHTSA

also disagreed with ATA's statement that the requirement for two

malfunction indicators unreasonably complicates the electrical systems

in combination vehicles, based on comments by brake and vehicle

manufacturers stating that it was appropriate to have an indicator in

the towing unit cab.

\12\ ``An In-Service Evaluation of the Performance, Reliability,

Maintainability, and Durability of Antilock Braking Systems for

Semitrailers,'' U.S. Department of Transportation/NHTSA Report No.

DOT HS 808 059, October 1993.

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In response to the December 1995 final rule, the Industry Consensus

Position stated that ultimately it is essential to provide drivers an

in-cab indication of a trailer(s) ABS malfunction, but that requiring

the in-cab indicator by 1997 would likely impede the implementation of

a new high speed data transmission protocol SAE J1939 that is now being

developed by the SAE. This new protocol is expected to become the

recognized method for providing signaling capability between tractors

and trailers for a wide variety and number of devices and systems,

including trailer ABS malfunction indications. The Industry Consensus

Position is that delaying the implementation date of the in-cab

malfunction warning requirement for trailer ABS malfunctions to March

1, 2001, would provide sufficient time to fully develop the SAE J1939

protocol and would thus preclude the need for a two-step implementation

process.

Based on information provided in the petitions, NHTSA has decided

to grant the requested delay for the trailer in-cab malfunction

indicator. By delaying the requirement, the agency will enable the

manufacturers to move directly and promptly to in-cab failure

indicators that will use the new SAE protocol, thereby saving the cost

of installing indicators based on current technology. The delay will

also avoid the compatibility problems between new and old tractors and

trailers in the field and the associated costs and potential

maintenance problems associated with such a transition. The petitions

indicate a strong commitment to develop an SAE J1939-based final

solution. The agency anticipates that heavy vehicle manufacturers and

users will be able to develop and implement SAE J1939 and that further

delays in the implementation of this requirement will neither be

requested nor necessary.

NHTSA further notes that the external trailer indicator will still

advise a driver about a trailer ABS malfunction during this interim

period, when an in-cab indicator is not required. Notwithstanding the

need to rely on the external trailer indicator during this interim

period, NHTSA continues to view the in-cab trailer ABS malfunction

indicator as the best method for informing a driver of a trailer ABS

malfunction, based on the data and other information referenced in the

final rule.

C. External Trailer Malfunction Indicator

In previous notices, NHTSA emphasized the interrelationship between

the in-cab trailer malfunction indicator and the external trailer

malfunction indicator. In the September 28, 1993, notice of proposed

rulemaking (60 FR 13221, September 28, 1993) which led to the March

1995 final rule, the agency stated that the eight-year period for the

interim external trailer requirement was intended to represent the

average lifespan of a truck tractor and that

The external lamp would not be necessary on new trailers

manufactured after the end of that period because by that time, a

significant majority of tractors in the heavy vehicle fleet, which

would be responsible for the vast majority of miles driven by

tractors, would be manufactured in compliance with the requirement

for an in-cab lamp capable of receiving a malfunction signal from a

trailer.

In the final rule, the agency reiterated this view, although it

talked in terms of ``ABS and non-ABS equipped tractors'' as a shorthand

for tractors equipped with ABS malfunction indicators.

NHTSA's decision to delay the in-cab malfunction indicator for

trailer ABS from March 1, 1997 until March 1, 2001, will delay the

entry of tractors equipped with such indicators into the fleet. To

provide drivers of tractors without in-cab indicators with a warning of

trailer ABS failure, the agency has decided to extend the transition

period during which a trailer must be equipped with an external

malfunction indicator. The external indicators will be required from

March 1, 1998 until March 1, 2009, three years later than the date

established in the December 1995 final rule. Accordingly, a trailer

must still be equipped with an external ABS indicator during the time

period in which there is no in-cab trailer ABS malfunction indicator

requirement in effect as well as for an additional eight years after

the in-cab trailer malfunction indicator requirement takes effect. As

explained in previous notices, the additional eight-year transition

period represents the typical life cycle of tractors. Based on these

considerations, NHTSA has decided to amend S5.2.3.3 to require each

trailer (including a trailer converter dolly) manufactured on or after

March 1, 1998 and before March 1, 2009 to be equipped with an external

ABS malfunction indicator lamp.

IV. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

This notice has not been reviewed under Executive Order 12866.

NHTSA has considered the impacts of this rulemaking action and

determined that it is not ``significant'' within the meaning of the

Department of Transportation's regulatory policies and procedures. In

connection with the March 1995 final rules, the agency prepared a Final

Economic Assessment (FEA) describing the economic and other effects of

this rulemaking action. Summary discussions of those effects were

provided in the ABS final rule. For persons wishing to examine the full

analysis, a copy is in the docket.

The amendments in this final rule do not make those effects any

more stringent, and in some respects make it easier for a manufacturer

to comply with them. Specifically, by eliminating the requirement for

the dedicated ABS circuit and delaying the trailer in-cab malfunction

indicator by four years, tractor and trailer manufacturers will be able

to develop new methods of communicating trailer ABS information to the

tractor. Thus, for these four years, tractor manufacturers will not

have to provide a trailer in-cab malfunction indicator. After this four

year period, truck and trailer manufacturers will incur some additional

cost associated with ABS communications. This cost will depend on the

communication technique employed, i.e., multiplexing, Radio Frequency

(RF) signaling, or a separate circuit.

B. Regulatory Flexibility Act

NHTSA has also considered the effects of both this final rule or

the original final rule under the Regulatory Flexibility Act. I hereby

certify that it will not have a significant economic impact on a

substantial number of small

[[Page 5954]]

entities. Accordingly, the agency has not prepared a final regulatory

flexibility analysis.

NHTSA concluded that the March 1995 final rule had no significant

impact on a substantial number of small entities. Thus, the revised

final rule, which temporarily reduces costs associated with the March

1995 final rule, will not have a significant economic impact on a

substantial number of small entities.

C. National Environmental Policy Act

NHTSA has analyzed this rulemaking action for the purposes of the

National Environmental Policy Act. The agency has determined that

implementation of this action will not have any significant impact on

the quality of the human environment.

D. Executive Order 12612 (Federalism)

NHTSA has analyzed this action under the principles and criteria in

Executive Order 12612. The agency has determined that this notice does

not have sufficient Federalism implications to warrant the preparation

of a Federalism Assessment. No State laws will be affected.

E. Civil Justice Reform

This final rule does not have any retroactive effect. Under 49

U.S.C. 30103, whenever a Federal motor vehicle safety standard is in

effect, a State may not adopt or maintain a safety standard applicable

to the same aspect of performance which is not identical to the Federal

standard, except to the extent that the State requirement imposes a

higher level of performance and applies only to vehicles procured for

the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial

review of final rules establishing, amending or revoking Federal motor

vehicle safety standards. That section does not require submission of a

petition for reconsideration or other administrative proceedings before

parties may file suit in court.

List of Subjects in 49 CFR Part 571

Imports, Motor vehicle safety, Motor vehicles, Rubber and rubber

products, Tires.

In consideration of the foregoing, the agency is amending Standard

No. 121, Air Brake Systems, in title 49 of the Code of Federal

Regulations at part 571 as follows:

PART 571--[AMENDED]

1. The authority citation for part 571 continues to read as

follows:

Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166,

delegation of authority at 49 CFR 1.50.

2. Section 571.121 is amended by revising S5.1.6.2(b), S5.1.6.3,

S5.2.3.2, S5.2.3.3 and S5.5.2 to read as follows:

Sec. 571.121 Standard No. 121; Air brake systems.

* * * * *

S5.1.6.2 Antilock malfunction signal.

* * *

(b) Each truck tractor manufactured on or after March 1, 2001, and

each single unit vehicle manufactured on or after March 1, 2001, that

is equipped to tow another air-braked vehicle, shall be equipped with

an electrical circuit that is capable of transmitting a malfunction

signal from the antilock brake system(s) on one or more towed

vehicle(s) (e.g., trailer(s) and dolly(ies)) to the trailer ABS

malfunction lamp in the cab of the towing vehicle, and shall have the

means for connection of this electrical circuit to the towed vehicle.

Each such truck tractor and single unit vehicle shall also be equipped

with an indicator lamp, separate from the lamp required in S5.1.6.2(a),

mounted in front of and in clear view of the driver, which is activated

whenever the malfunction signal circuit described above receives a

signal indicating an ABS malfunction on one or more towed vehicle(s).

The indicator lamp shall remain activated as long as an ABS malfunction

signal from one or more towed vehicle(s) is present, whenever the

ignition (start) switch is in the ``on'' (run) position, whether or not

the engine is running. The indicator lamp shall also be activated as a

check of lamp function whenever the ignition is turned to the ``on'' or

``run'' position. The indicator lamp shall be deactivated at the end of

the check of lamp function unless a trailer ABS malfunction signal is

present.

* * * * *

S5.1.6.3 Antilock power circuit for towed vehicles. Each truck

tractor manufactured on or after March 1, 1997, and each single unit

vehicle manufactured on or after March 1, 1998, that is equipped to tow

another air-braked vehicle shall be equipped with one or more

electrical circuits that provide continuous power to the antilock

system on the towed vehicle or vehicles whenever the ignition (start)

switch is in the ``on'' (run) position. Such a circuit shall be

adequate to enable the antilock system on each towed vehicle to be

fully operable.

* * * * *

S5.2.3.2 Antilock malfunction signal. Each trailer (including a

trailer converter dolly) manufactured on or after March 1, 2001, that

is equipped with an antilock brake system shall be equipped with an

electrical circuit that is capable of signaling a malfunction in the

trailer's antilock brake system, and shall have the means for

connection of this antilock brake system malfunction signal circuit to

the towing vehicle. The electrical circuit need not be separate or

dedicated exclusively to this malfunction signaling function. The

signal shall be present whenever there is a malfunction that affects

the generation or transmission of response or control signals in the

trailer's antilock brake system. The signal shall remain present as

long as the malfunction exists, whenever power is supplied to the

antilock brake system. Each message about the existence of such a

malfunction shall be stored in the antilock brake system whenever power

is no longer supplied to the system, and the malfunction signal shall

be automatically reactivated whenever power is again supplied to the

trailer's antilock brake system. In addition, each trailer manufactured

on or after March 1, 2001, that is designed to tow another air-brake

equipped trailer shall be capable of transmitting a malfunction signal

from the antilock brake system(s) of additional trailers it tows to the

vehicle towing it.

* * * * *

S5.2.3.3 Antilock malfunction indicator. In addition to the

requirements of S5.2.3.2, each trailer (including a trailer converter

dolly) manufactured on or after March 1, 1998, and before March 1,

2009, shall be equipped with an external indicator lamp that is

activated whenever there is a malfunction that affects the generation

or transmission of response or control signals in the trailer's

antilock brake system. The indicator lamp shall remain activated as

long as such a malfunction exists, whenever power is supplied to the

antilock brake system. Each message about the existence of such a

malfunction shall be stored in the antilock brake system whenever power

is no longer supplied to the system, and the malfunction signal shall

be automatically reactivated when power is again supplied to the

trailer's antilock brake system. The indicator lamp shall also be

activated as a check of lamp function whenever power is supplied to the

antilock brake system and the vehicle is stationary. The indicator lamp

shall be deactivated at the end of the check of lamp function unless

there is a malfunction or a message about a malfunction that existed

when power

[[Page 5955]]

was last supplied to the antilock brake system.

* * * * *

S5.5.2 Antilock system power--trailers. On a trailer (including a

trailer converter dolly) manufactured on or after March 1, 1998 that is

equipped with an antilock system that requires electrical power for

operation, the power shall be obtained from the towing vehicle through

one or more electrical circuits which provide continuous power whenever

the powered vehicle's ignition (start) switch is in the ``on'' (run)

position. The antilock system shall automatically receive power from

the stoplamp circuit, if the primary circuit or circuits are not

functioning. Each trailer (including a trailer converter dolly)

manufactured on or after March 1, 1998 that is equipped to tow another

air-braked vehicle shall be equipped with one or more circuits which

provide continuous power to the antilock system on the vehicle(s) it

tows. Such circuits shall be adequate to enable the antilock system on

each towed vehicle to be fully operable.

* * * * *

Issued on: February 12, 1996.

Ricardo Martinez,

Administrator.

[FR Doc. 96-3382 Filed 2-13-96; 8:45 am]

BILLING CODE 4910-59-P