Federal Motor Vehicle Safety Standards; School Bus Body Joint Strength

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-98-4662]

RIN 2127-AC19

Federal Motor Vehicle Safety Standards; School Bus Body Joint

Strength

AGENCY: National Highway Traffic Safety Administration (NHTSA),

Department of Transportation.

ACTION: Final rule.

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SUMMARY: This rule amends Federal Motor Vehicle Safety Standard No.

221, School Bus Body Joint Strength (49 CFR 571.221), which requires

school bus body panel joints to be capable of holding the body panel to

the member to which it is joined when subjected to a force of 60

percent of the tensile strength of the weakest joined body panel.

Currently, the standard applies only to school buses with a gross

vehicle weight rating (GVWR) greater than 10,000 pounds. This rule

extends the applicability of the standard to school buses with a GVWR

of 10,000 pounds or less, narrows an exclusion of maintenance access

panels from the requirements of the standard, and revises testing

requirements.

This rule ensures that children are provided equivalent levels of

protection against joint separation in small as well as large school

buses. Since a larger proportion of small school buses than of large

school buses are lift-equipped to transport mobility impaired students

compared to large buses, this rule particularly enhances the safety of

mobility impaired children.

DATES: This rule is effective May 5, 2000. Optional early compliance

with the changes made in this final rule is permitted beginning

November 5, 1998. Any petitions for reconsideration of this final rule

must be received by NHTSA not later than December 21, 1998.

ADDRESSES: Petitions for reconsideration should refer to the docket

number for this action and be submitted to: Administrator, National

Highway Traffic Safety Administration, 400 Seventh Street, SW,

Washington, DC 20590. Copies of the Final Regulatory Evaluation for

this rule can be obtained from: Docket Management, Room PL-401, 400

Seventh Street, SW, Washington, DC, 20590, telephone: (202) 366-9324.

Docket hours are 10 a.m. to 5 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: Mr. Charles R. Hott, Office of

Crashworthiness Standards, National Highway Traffic Safety

Administration, 400 Seventh Street SW, Washington, DC 20590, (202) 366-

0247.

SUPPLEMENTARY INFORMATION:

I. Summary of the Final Rule

II. Background

II. Amendments

A. Applicability to small school buses

B. Maintenance access panels

C. Other issues relating to exclusions

D. Test procedures

E. Other issues

IV. Rulemaking Analyses and Notices

A. EO 12866; DOT Regulatory Planning and Review and DOT Policies

and Procedures

B. Regulatory Flexibility Act

C. Paperwork Reduction Act

D. National Environmental Policy Act

E. Executive Order 12612 Federalism

F. Civil Justice Reform

I. Summary of the Final Rule

This rule is intended to enhance the applicability and objectivity

of Standard No. 221's school bus joint strength requirements. The

standard currently applies only to large school buses (GVWR greater

than 10,000 pounds). The standard specifies strength requirements for

each ``body panel joint,'' which is currently defined as the area of

contact or close proximity between the edges of a body panel and

another body component, excluding spaces designed for ventilation or

another functional purpose, and excluding doors, windows, and

maintenance access panels (MAPs).

This rule extends the applicability of Standard No. 221 to small

school buses (GVWR of 10,000 pounds or less) and narrows the present

exclusion of MAPs from the joint strength requirements. Except as noted

below, the rule requires panels to be attached at least at every 8

inches (203 millimeters (mm)), and requires body panel joints to

withstand a tensile strength of 60 percent of the tensile strength of

the weakest joined body panel. Excluded from these requirements are

MAPs outside of the passenger area, and MAPs, smaller than a specified

size, inside the passenger area. Joints from which a test sample cannot

be obtained because of the joint's size or the curvature of the panels

comprising the joint, are excluded from the tensile strength

requirements.

Some of the definitions adopted by this rule differ from the NPRM.

For example, the rule simplifies the definition of ``maintenance access

panel,'' and adopts a definition of ``passenger compartment'' based on

the definition in Standard No. 217, Bus Emergency Exits and Window

Retention and Release (49 CFR 571.217). The proposal for deleting the

``hourglass'' shape of the test specimen has not been adopted.

II. Background

NHTSA is authorized by 49 U.S.C. 30101, et seq., to issue Federal

motor vehicle safety standards for new motor vehicles, including school

buses.1 In 1974, Congress enacted the Motor Vehicle and

Schoolbus Safety Amendments (Pub. L. 93-492), which directed NHTSA to

issue Federal motor vehicle safety standards for various aspects of

school bus safety, including interior protection for occupants, floor

strength, and crashworthiness of body and frame. In response to that

Congressional mandate, NHTSA issued Standard No. 221, School Bus Body

Joint Strength.

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\1\ 49 U.S.C. 30125(a)(1) defines a schoolbus as a passenger

motor vehicle designed to carry a driver and more than ten

passengers that the Secretary of Transportation determines ``is

likely to be used significantly to transport preprimary, primary,

and secondary school students to or from school or an event related

to school.'' NHTSA further defines a school bus as a bus that is

sold or introduced in interstate commerce for purposes that include

carrying students to and from school and related events, but does

not include a bus that is designed and sold for operation as a

common carrier in urban transportation. 49 CFR 571.3.

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Standard No. 221 requires the strengthening of school bus body

panel joints to prevent these joints from separating during a crash and

becoming cutting edges that could cause serious injuries or allowing

passenger ejection through openings created by such panel separations.

The standard currently provides that each school bus body panel joint

must be capable of holding the body panel to the member to which it is

joined when subjected to a force of 60 percent of the tensile strength

of the weakest joined body panel. Excluded from this requirement are

doors, windows, spaces designed for ventilation or another functional

purpose, and MAPs. MAPs were excluded because they involve areas on the

vehicle requiring frequent maintenance and need to have unrestricted

accessibility. Although MAPs were not defined in the standard, it was

NHTSA's intent that manufacturers would limit MAPs to panels providing

access to areas requiring routine maintenance.

Maintenance access panels (MAPs). The exception of MAPs from

Standard No. 221 has been an issue of concern to NHTSA, the National

Transportation Safety Board (NTSB), and school bus

[[Page 59733]]

manufacturers. Through information provided by manufacturers and

inspection of buses being built in the years following the effective

date of the standard in 1977, NHTSA learned that most manufacturers

created MAPs that ranged from a few inches up to 12 inches wide above

the window area and extending the entire length of the bus. In

addition, nearly the entire rear wall of some buses was designated as a

MAP.

In testing some of those MAPs after the effective date of the

standard, the agency found the panels to be loosely attached and unable

to withstand much force before detaching from the bus body or adjacent

panels. For example, NHTSA's inspections of a variety of school bus

makes and models disclosed that MAPs extending the length of the bus

above the windows were not fastened down, but were held in place only

by the window frames. On the other hand, NHTSA observed that in some

buses which had been involved in crashes, panels that complied with the

standard performed very well and rarely detached from the bus body and

adjacent panels.

To correct the perceived MAP problem, NHTSA issued a notice of

proposed rulemaking on November 27, 1981 (46 FR 57939) proposing to

remove the exemption for all maintenance access panels except for a few

that were considered critical for proper maintenance.

Over 200 comments were received in response to that notice, all but

two of which opposed the proposed amendments. In addition, public

meetings were held on these issues in March 1982, and again in January

1983. Commenters on the notice and representatives of interested

parties at the meetings contended that NHTSA could show no safety

problem or abuse of the standard and no injuries attributed to MAP

failure, and that extra fasteners could delay proper maintenance

because of difficulties in removing them. They also suggested that the

additional cost of compliance might be $500 per bus with no greater

safety benefits, and that the proposals could include other previously

excluded joints unrelated to MAPs.

NHTSA conducted an internal review of the comments received and

available crash data and concluded that the assertions of the

commenters had substantial merit. The agency was not able to locate a

documented case of personal injury resulting from MAP failure, and was

unable to identify any specific instances of abuse of the MAP

exclusion. The agency believed, however, that the potential for abuse

existed and urged manufacturers to limit their use of MAPs to those

areas where such panels were clearly necessary. The agency also agreed

that requiring extra fasteners on MAPs might not enhance safety because

an increase in fasteners or a decrease in MAPs could complicate the

maintenance process, thus discouraging prompt maintenance. Finally, the

agency concluded that increased compliance costs could be detrimental

to safety by inducing owners of older buses to keep them longer than

they normally would, without a safety benefit. In view of these

considerations, NHTSA terminated the rulemaking on July 2, 1984 (49 FR

27181), but nevertheless urged bus manufacturers to minimize the number

of MAPs.

Although NHTSA terminated the rulemaking, NHTSA continued to

consider the matter in light of additional information received after

the termination, such as documentation of MAP separations in actual

crashes that caused injuries, and evidence that some previously-

complying panels had been redesignated as MAPs. The NTSB, in several

recommendations based on a number of serious school bus accidents

occurring after the termination, proposed elimination of the exclusion

for MAPs and recommended other improvements in school bus safety. The

NTSB also indicated that joint separation had occurred in crashes

involving small school buses.

In June 1987, NHTSA issued an advance notice of proposed rulemaking

(ANPRM) (52 FR 23314; June 19, 1987) on school bus body joint strength

issues. The ANPRM requested comments on possible proposals to specify

minimum strength requirements for the floors of school buses with a

GVWR over 10,000 pounds, narrow the MAP exclusion from the joint

strength requirements of Standard No. 221, and revise the test

procedures of the standard.

Thirty-seven comments were received in response to the ANPRM,

including comments from school bus manufacturers, school bus operators,

and Federal, state and local governmental agencies. After considering

all comments and completing a series of dynamic tests of school bus

floor joints, NHTSA published a notice of proposed rulemaking on March

15, 1991 (56 FR 11142) (hereinafter NPRM), proposing to: (1) Extend the

applicability of Standard 221 to small school buses (GVWR 10,000 pounds

or less); (2) narrow the existing exclusion of MAPs; and (3) expand

testing requirements and clarify testing procedures for school bus body

panel joints.

NHTSA received 18 comments to the NPRM. Commenters included seven

school bus manufacturers, one equipment supplier, six state

organizations, three trade and citizens' associations, and one private

citizen. All comments were fully considered and the significant ones

are addressed below.

III. Amendments

A. Applicability to Small School Buses

This rule extends the applicability of Standard No. 221 to small

school buses (GVWR 10,000 pounds or less), as proposed.

Commenters were divided in their support of NHTSA's proposal to

extend the standard to small school buses. The Maryland State

Department of Education (MSDE), Maryland Motor Vehicle Administration

(MMVA), Washington Superintendent of Public Instruction (SPI),

Connecticut Department of Motor Vehicles (CDMV), California Department

of Education (CDE), and the Blue Bird Body Company (Blue Bird) all

expressed support for the proposal. In general, the state agencies

believed that small school buses should offer the same passenger

protection as large school buses. Blue Bird stated that although there

does not appear to be sufficient safety need or cost benefit

justification for extending the requirements of Standard No. 221 to

small school buses, the company supports the proposal in the interest

of providing uniform safety levels in all school buses and because use

of small school buses is growing.

Commenters opposed to the extension of Standard No. 221 to small

school buses were Collins Industries (Collins), National Truck

Equipment Association on behalf of the Manufacturers Council of Small

School Buses (MCSSB), General Motors Corporation (GM), Ford Motor

Company (Ford), and Mid Bus Inc. (Mid Bus). Most of these commenters

believed that the findings of the NTSB were insufficient to establish a

safety need to extend the standard to small school buses.

The agency disagrees, and believes there is a safety need to extend

the standard to small school buses. NTSB was concerned that small

school buses experience higher crash forces in a crash than do large

school buses, since size and mass are important factors in crash

severity. The NTSB studies on the crashworthiness of large and small

school buses found that 6 of 19 small school bus crashes resulted in

body panel joint separation (32 percent of the cases studied). In

contrast, joint separations in large school buses

[[Page 59734]]

occurred in MAPs and floor joints, while body panel joints maintained

structural integrity very well, even in severe crash forces. These

results indicate that the requirements of Standard 221 are very

effective (see NTSB Safety Study: Crashworthiness of Small Poststandard

School Buses, October 11, 1989). Further, these results lead NHTSA to

conclude that the structural integrity of small buses would be enhanced

by the joint strength requirement of Standard 221. NHTSA concludes that

small school buses should at least be subject to the same joint

strength requirements as large school buses. This will better ensure

that all children are provided equivalent levels of protection against

injuries from joint separation, regardless of the GVWR of the vehicle

transporting them.

Small school buses are becoming an increasingly larger part of the

school bus fleet. From 1988 to 1993, the percentage of total school bus

sales for small school buses rose from about 13 percent to about 19

percent (an increase of almost 50 percent in market share). From 1994

to the present, the percentage of small school bus sales has been

holding steady at about 16 percent. This rise of sales is of concern

because it indicates that crashes, and resultant injuries, are likely

to increase.

Moreover, the agency notes that a larger proportion of small school

buses than of large buses are lift-equipped to transport mobility

impaired students. The school bus industry describes Type A and Type B

school buses as being for ``disability/special purpose'' use. Extending

Standard No. 221's requirements to small school buses thus enhances the

safety of mobility impaired children. In addition, these buses may

frequently be used to carry pre-primary, Head Start program children.

GM stated that small school buses are already subject to standards

not applicable to large school buses, such as Standard Nos. 204, 208,

209, 210, 212, 219, and 301. Therefore, GM argued, a vehicle built in

compliance with those standards has inherent structural integrity and

occupant protection. Collins and MCSSB stated that small school buses

actually have a double approach to passenger protection and restraint

in crashes since they are subject to the compartmentalization

requirements of large school buses as well as the seat belt

requirements of Standard No. 208, Occupant Crash Protection.

NHTSA is not persuaded by these comments. The standards cited by GM

help ensure the crashworthiness of a small school bus, but those

standards address safety systems that are not directly relevant to

school bus body panel joint integrity. For example, Standard No. 204

limits the rearward displacement of the steering control into the

passenger compartment; 208, 209 and 210 address the occupant belt

systems; 212 and 219 pertain to retention and intrusion of the

windshield; and 301 addresses the vehicle's fuel system integrity.

Similarly, in response to Collins and MCSSB, the fact that small school

buses must comply with seat belt requirements and most (but not all) of

the compartmentalization requirements of Standard No. 222 is irrelevant

to the issue of upgrading the integrity of the bus body. The seat belt

and compartmentalization requirements for small school buses help

ensure that the passenger is restrained safely. Standard No. 221

regulates the lap joint construction method used to manufacture school

bus bodies. The joint strength requirements will help ensure that the

environment in which the passenger is restrained does not lose

structural integrity in a crash. NHTSA views the occupant restraint and

compartmentalization requirements of Standards No. 208 and 222 as

complementing the joint strength requirements of Standard No. 221, and

not as requirements that obviate the need for them.

MCSSB argued that the cost to manufacturers of bringing small

school buses into compliance with Standard No. 221 would be

prohibitive, considering the need for complete joint analysis, testing

and certification programs, and possible material and design changes.

Mid Bus estimated that having to comply with Standard No. 221

requirements would increase the cost of a small school bus by $1,982

(1996 dollars).2

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\2\ All costs shown are in terms of 1996 dollars unless

otherwise noted.

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The agency disagrees that the cost impact of the rule on small

school buses is unreasonable. Currently, 21 states and the District of

Columbia already require small school buses to comply with the joint

strength requirements of Standard No. 221 at an additional cost ranging

from $91 to $1,087 per vehicle. NHTSA estimates that the sales-weighted

average increase in the consumer cost of a small school bus to comply

with both the joint strength and the MAP requirements would be $343

(for a more detailed discussion of costs, including the cost impacts of

the rule on large school buses, see the discussion of NHTSA's Final

Regulatory Evaluation in the section on Rulemaking Analyses and

Notices, below). All small school bus manufacturers already produce, at

the purchaser's option, small school buses with body panel joints that

comply with Standard No. 221. NHTSA believes, therefore, that extending

the requirements of the standard to all school buses would not create

an undue burden or expense for small school bus manufacturers since

they are already tooled up for producing complying small school buses.

MCSSB expressed concern that chassis manufacturers would refuse to

certify their chassis, forcing small school bus manufacturers to

certify the chassis themselves or go out of business. Ford and Mid Bus

also alluded to the potential problem of chassis manufacturers refusing

to certify their chassis.

NHTSA does not believe the impacts of this rule on final-stage

manufacturers will be unduly burdensome. As noted above, many states

currently require small school buses to meet the joint strength

requirements of Standard No. 221. Any final-stage school bus

manufacturer producing a vehicle for sale in one of these states is

already taking the necessary steps toward fulfilling its contractual

obligations to meet Standard No. 221. In addition, any final-stage

manufacturer of school buses is also required to meet the

compartmentalization requirements of Standard No. 222, the

crashworthiness requirements of Standard Nos. 204, 208, 209, 210, 212,

219, and 301 (as mentioned by GM, above), as well as the comprehensive

series of FMVSSs that apply to school buses (e.g., Standard No. 217 for

emergency exits and No. 108 for school bus lights). The commenters did

not provide any information to demonstrate that a final-stage

manufacturer, who is capable of fulfilling its present obligation to

certify its vehicles to the extensive school bus safety standards,

would be unable to certify to Standard No. 221. Moreover, Standard No.

221 specifies a relatively simple static-pull test procedure that

manufacturers who choose to perform the test would not find burdensome

to conduct. In contrast, Standards No. 212, 219 and 301 specify dynamic

crash tests, and Standard No. 222 call for force applications and the

calculation of head injury criterion values. NHTSA believes that, given

the present certification responsibilities of final-stage manufacturers

of small school buses and the level of testing necessary to test to

FMVSS No. 221, these manufacturers have the means necessary to certify

their vehicles to Standard No. 221, even in the absence of assurances

from the chassis manufacturer. This assumes that

[[Page 59735]]

the chassis manufacturer would not provide such assurances. The agency

believes that the provision in the rule that excludes joints that can

not be physically accommodated in the tensile testing apparatus from

the 60 percent joint strength requirement will make it easier for more

chassis manufacturers to provide assurances to final-stage

manufacturers that the joints on the incomplete vehicle meets Standard

No. 221.

B. Maintenance Access Panels

NHTSA is defining ``maintenance access panel'' to limit a

manufacturer's latitude to designate panels as MAPs and thus be

excluded from the strength requirements of the standard. Under this

rule, to be excluded from the requirements of Standard No. 221 as a

``maintenance access panel,'' a panel must meet the definition of a

MAP, and must also meet certain criteria.

Definition. The definitions pertaining to maintenance access panels

are the same as those proposed in the NPRM. This rule defines

``maintenance access panel'' as ``a body panel which must be moved or

removed to provide access to one or more serviceable component(s).''

This rule also defines ``serviceable component'' as a part of the bus

which is identified by the body or chassis manufacturer in the owners'

or service manuals as requiring routine maintenance at least once each

year. The definition specifies that ``serviceable component'' includes

pneumatic and hydraulic devices, wiring harnesses, and tubing only at

their attachments.

Criteria to be Excluded. However, the rule differs from the NPRM in

setting criteria that a MAP must meet to be excluded from the

requirements of Standard No. 221. To be excluded, the MAP must either:

(1) Be located forward of the passenger seating area (the MAP must not

lie between a vertical transverse plane located 762 mm (30 inches) in

front of the forwardmost passenger seating reference point and a

vertical transverse plane tangent to the rear interior wall of the bus

at the vehicle's centerline); or (2) be located within the passenger

seating area but have an opening that does not exceed 305 mm (12

inches) when measured across any two points diametrically on opposite

sides of the opening.

In the NPRM, NHTSA proposed that any MAP that exposes the bus

interior to areas below the floor, to the engine compartment or to

compartments adjoining the engine compartment, would not be excluded,

regardless of where in the bus interior the MAP was located. NHTSA also

proposed that MAPs, other than those exposing the interior to areas

below the floor or to the engine compartment or to compartments

adjoining the engine compartment, which were in the passenger seating

area had to meet size limits to be excluded from the joint strength

requirements, ensuring that the MAP is no larger than required to

provide access to the serviceable components the MAP covered. The

proposed size limits provided a two-inch access margin around the

periphery of serviceable components or clusters of components for

handling and tool clearance during installation, replacement,

inspection and adjustment procedures. The average spacing between

components within a cluster of components covered by a single MAP could

not exceed four inches.

Five manufacturers, two associations, and two state organizations

commented on the proposal to narrow the exclusion of MAPs. The SPI and

the California Highway Patrol (CHP) concurred with the proposal to

restrict the size and locations of MAPs. SPI asserted that the present

exclusion compromises the safety and structural integrity of school

buses and that the proposed changes reflect a realistic limitation on

the use of access panels.

Commenting in opposition to the NPRM, Thomas and Mid Bus asserted

that there was not sufficient need shown to restrict MAPs. NHTSA

disagrees. After reviewing both NTSB studies as well as reviewing

recent NTSB school bus crash investigation reports, the agency found 7

out of 80 crashes studied involved MAP separations, causing head

laceration injuries in two of the cases. In 4 of the 20 crashes

involving small school buses, body joint separations occurred,

resulting in one occupant with multiple leg fractures. Further, NHTSA's

own tests have shown that MAP joints are not strong and can and do

separate easily.

Navistar International Transportation Corporation (Navistar),

National School Transportation Association (NSTA), MCSSB, and Blue Bird

expressed concern that restricting MAPs as proposed would make required

maintenance too difficult and time-consuming. They argued that

mechanics would not take the time to replace all the fasteners to

restore body panel joints to the 60 percent joint strength, and that

mechanics would experience more cuts and abrasions because of tighter

working areas. Those conditions could result in improperly accomplished

maintenance, delays in required maintenance, increased failure of

improperly-maintained parts, increased maintenance costs, and increased

injuries because of the smaller sizes of the panels. Thomas, Mid Bus,

and NSTA argued that the size restriction is too stringent. Mid Bus

suggested an alternative restriction, i.e., that the MAP should be no

smaller than 92,903 square millimeters (mm2) or 144 square

inches (in2).

NHTSA can not agree with commenters that the proposed MAP

restrictions will necessarily result in maintenance personnel not

replacing all the fasteners after opening or removal. NHTSA believes

that manufacturers are capable of designing their MAPs in such a manner

as to minimize potential problems. For example, school bus designers

and engineers may be able to redesign their current MAPs to provide

fewer fasteners for mechanics to replace. Nevertheless, NHTSA has

decided that the proposed limitations on MAP size are too restrictive.

Clearance of two inches on a side in servicing components does not

appear to be sufficient. After considering other alternatives for MAP

exclusions, NHTSA has decided to exclude from the joint strength

requirements of Standard No. 221 those maintenance access openings that

do not exceed 305 mm (12 inches) when measured across any two points

diametrically on opposite sides of the opening. That measurement is

independent of the serviceable component's perimeter and location. The

adopted restriction will ensure that MAPs are no larger than needed to

provide access to the serviceable components the MAP covered. The

proposed 102 mm (4 inches) average maximum distance limitation between

components has not been adopted since no such component clusters have

been identified either by NHTSA or by the commenters.

Engine access panels. Thomas and Navistar asserted that because

engines need sometimes daily maintenance, engine covers should be

excluded wherever located. NHTSA believes that most front engine buses

have engine covers that are located outside the defined passenger

compartment area and that maintenance on rear engine buses is routinely

accomplished from the outside. Nevertheless, the agency agrees that

direct and often-recurring engine maintenance should be quickly and

easily accomplished. This includes easy accessibility to the engine

compartment by the driver who may not have an extensive array of tools

available. Accordingly, NHTSA has decided that engine access panels

will be excluded from the requirements of the standard.

MAP floor panels. MAPs that expose the bus interior to areas

located below

[[Page 59736]]

the bus floor or within the engine compartment are excluded from

Standard No. 221's requirements if the MAP meets the restrictions on

either MAP location or size described above. The NPRM did not provide

for conditions whereupon interior MAP floor panels or interior MAPs

leading into the engine compartment could be excluded from Standard No.

221. This was because NHTSA believed these panels should be universally

required to comply with the joint strength requirement since the panels

serve to isolate the bus interior from areas where fire is most likely

to occur, and are an integral part of the vehicle's barrier against

passenger compartment fires. In commenting on the proposal, Blue Bird

asserted that subjecting floor panels to the body panel strength

requirements is an unjustified extension of the standard that would do

little to provide fire protection for the passenger compartment. NSTA

stated that the strength of a joint has little or no relation to its

effectiveness as a firestop.

It was NHTSA's intent in making the proposal to protect passengers

as much as possible from fire entering the passenger compartment

through a separated floor panel, as well as to prevent passengers from

being ejected through a separated floor panel. Even though compliance

with the joint strength requirement may not render a floor panel

fireproof, proper joint strength may prevent the panel from separating.

This would, in turn, help confine a fire to the area outside the

passenger compartment, thereby allowing passengers more time to

evacuate the vehicle. However, NHTSA agrees that there is an

insufficient fire-related reason at this time to require any MAP,

regardless of its location outside the bus occupant space or

insignificant size, to meet the joint strength requirement if it is on

the floor. Thus, the rule excludes MAPs on the floor of the vehicle if

the MAP is forward of the passenger compartment or is of a size small

enough to qualify the MAP for the exclusion.

C. Other Issues Relating to Exclusions

Ventilation. Currently, spaces designed for ventilation are

excluded from the body joint strength requirements, and this rule

continues that exclusion. The NPRM proposed to end the exclusion

because the agency believed that the exclusion is not being utilized

and therefore serves no useful purpose. However, Blue Bird and Thomas

informed NHTSA that that belief is not correct. Blue Bird stated that,

contrary to NHTSA's impression, ventilation panels are used for heater

housings, heater air diffusers, heater ducts, heater hose covers, and

air conditioning ducts and diffusers. Blue Bird argued that all those

components serve important functional purposes, that they enclose no

occupant air space, and are typically supported by panels that are

required to comply with the standard. Blue Bird further asserted that

eliminating this exclusion is not justified from a safety need and

would be overly burdensome in terms of cost and restricted access to

those components by maintenance personnel. Thomas stated that this

revision would result in increased costs from redesign and extra

fastening as well as decreased serviceability for the end user of the

vehicle.

After careful consideration of the comments of Thomas and Blue

Bird, NHTSA is persuaded that the ventilated panel exclusion is being

utilized and that ventilation panels do serve important functional

purposes. Further, due to their size and location, ventilation panels

are not as likely as first thought to cause occupant injuries in an

accident. NHTSA believes that extending the joint strength requirements

to these panels would result in increased costs for redesign and

additional fasteners, as well as decreased serviceability for the end

user, without a commensurate safety benefit. Therefore, ventilation

panels will continue to be excluded from the joint strength

requirements of Standard 221.

Perforated panels. Thomas stated that perforated metal sheets are

widely used in the interior linings of school buses to reduce interior

noise. Thomas stated that the perforations do not extend into the joint

area, making the joints stronger than the perforated portions of the

panels. Thomas asserted, therefore, that the perforated portions could

tear before the joints fail. Thomas suggested that NHTSA evaluate the

safety advantages and disadvantages of the use of perforated headlining

material to determine whether ``special considerations'' should be

given for such material.

NHTSA is aware that perforated material is often used in school bus

ceilings for noise reduction. The agency is unaware of any problems

with perforated panels, such as instances where perforations

contributed to the failure of a joint or where panels separated due to

torn perforations. Nevertheless, the agency will monitor the use of

perforated panels and their performance in school buses to determine

whether there is a safety need to limit or otherwise regulate their

use.

Curved and small joints. This rule excludes from the joint tensile

strength requirement joints from which a test sample cannot be obtained

because of the size of the joint or the curvature of the panels

comprising the joint.

The NPRM proposed a procedure for testing curved joints, such as

those found in roof or ceiling joints. The procedure would have

specified that the test specimen is prepared by selecting a joint

segment where the radius of curvature is at least 508 mm (20 inches).

Thomas suggested a method of testing a curved joint, but stated that in

order to prevent distortion of the test results, the gripping devices

must be able to grip the sample in the same radius as the sample

curvature. To avoid such complex test procedures, Thomas strongly

recommended that NHTSA approve the use of surrogate joints.

NHTSA recognizes that the curved shape of such joints poses

difficulty in obtaining accurate test results. The application of force

on a curved surface would cause the surface to flatten, thus

misrepresenting the actual force loading on the panel. Although NHTSA

believes that it is possible to design and fabricate test fixtures and

procedures capable of testing curved joints, such fixtures would

involve additional certification costs for manufacturers and additional

cost for NHTSA in the agency's compliance testing. Since the agency is

not aware of any data indicating that injuries have been caused

disproportionately by curved joint separation, NHTSA believes that the

potential costs and technical difficulty of testing curved joints more

than outweigh any potential safety benefits. However, the agency will

continue to monitor this issue and initiate rulemaking should curved

joint separation become a safety problem.

Thomas and GM commented on NHTSA's proposals to test small and

complex joints such as those taken from door, window, and other small

or inaccessible body panel joints. GM stated that NHTSA's proposals

regarding the testing of these joints did not fully clarify specimen

preparation procedures for such joints found in passenger vans or van

cutaways. The commenters contended that many of the joints in those

vehicles cannot be tested under either current or proposed testing

procedures. GM suggested that NHTSA further study such types of joints

and either further clarify pertinent test procedures or exclude such

joints from the requirements of Standard 221 as being nontestable.

Thomas asserted that the testing of very short pieces of frame that

would require fittings would violate ASTM test principles. Thomas

further

[[Page 59737]]

argued that tests need not be performed in this manner if NHTSA would

approve the use of surrogate sampling.

NHTSA agrees that complex joints such as those found in body panels

configured to join two or more panels in a single plane in any manner

other than linear, as well as other small joints, cannot feasibly be

tested under either current or proposed testing procedures.

Accordingly, NHTSA has decided that test specimens from joints with

discrete fasteners will be taken from 305 mm (12 inch) segments (203 mm

(8 inches) at the neck) of only flat body panels. Small and complex

joints, as well as trim, decorative parts, floor coverings, and molding

strips will not be tested. The agency has no data indicating that any

injuries have been caused by failure of those small and complex joints

or components, and NHTSA believes that the potential cost of trying to

test them would far outweigh any potential safety benefits.

While curved, small and complex joints are excluded from the

tensile test requirement because they cannot be accommodated on the

test apparatus, they are nevertheless subject to the requirement in

S5.1.1 that no body panel, when joined to another body panel, shall

have an unattached segment at the joint longer than 203 mm (8 inches).

Presumably rivets or other fasteners will be used. This requirement

helps ensure that the joints will maintain their integrity in a crash.

D. Test Procedures

This rule makes a number of revisions to Standard No. 221's test

procedures, including adopting a provision that support members must

remain attached to the specimen during testing; and that the term

``approximately perpendicular'' be deleted from S6.3.2 and replaced by

a provision that the joint be in stress at 90 degrees plus or minus 3

degrees from the joint centerline. The parts of the NPRM proposing

these changes did not engender opposition.

In contrast, the proposal that the existing ``hourglass'' shape of

test specimens be eliminated in favor of straight sides was strongly

opposed by Thomas and Blue Bird. The idea behind the proposal was that

with a simple rectangular shape, more joints could potentially be

tested. However, Thomas stated that a straight-sided test specimen was

contrary to the shape principles set forth in the ASTM sample testing

procedures. Those principles were designed to ``even-out'' the force

distortions induced by the testing device. Blue Bird stated that the

proposal to eliminate the hour glass shape was unacceptable, arguing

that the test specimens need to be wider at the grips than at the joint

section being tested. It said that this width is needed to allow for

proper attachment of the specimen to the test grips and to ensure that

adequate loading can be properly applied to the joint portion of the

specimen.

NHTSA is persuaded by the comments of Thomas and Blue Bird and has

decided to retain the hourglass shape of test specimens. The ASTM

Standards call for the shape of the test specimen to be narrower at the

sample's longitudinal centerline than at the ends of the specimen where

the grips are attached. That shape concentrates the load exerted by the

grips in the center of the specimen rather than at the edges as in the

case of a straight-sided specimen.

Another proposal that generated opposition was the proposed

discontinuance of the deduction of the total area of material removed

for installation of fasteners (i.e., holes drilled for installation of

rivets or screws) in calculating the tensile strength of each joined

component. Thomas asserted that the proposal was not logical because

the removal of material to make the fastener holes does in fact reduce

the cross-sectional area being tested. Further, the commenter said that

the change proposed by NHTSA would have the effect of increasing the

joint strength required to meet the test. Blue Bird alluded to the

NHTSA interpretation letter to that company dated November 28, 1978,

which was the basis for the proposal. In that letter, NHTSA stated that

subtracting the fastener holes was the proper procedure for calculating

the correct area of the sample, but did not explain the basis for that

conclusion. Blue Bird urged that subtracting the fastener holes is the

correct method of calculating the area of the sample.

NHTSA has carefully considered this issue in light of the comments

of Thomas and Blue Bird. It is easier for a sample joint to meet the

standard's tensile strength requirement when the deduction is made for

fastener holes. As previously discussed in this notice, the required

strength of a given joint is based on the tensile strength of the

weakest body panel attached at that joint. If the area for fastener

holes were deducted from the total area of the test specimen when

calculating the strength of the test specimen, the tensile strength of

a sample joint could appear higher than the actual tensile strength of

that joint. As a result, a given joint could meet the 60 percent

tensile requirement of Standard 221 using fewer fasteners than those

that would be necessary if the deduction were not made. In setting the

60 percent tensile requirement, the agency determined that minimum

value met the need for motor vehicle safety. Since deducting for

fastener holes can result in a joint being actually weaker than 60

percent of its weakest member, safety is better served if the deduction

were not made. Accordingly, the letter of interpretation issued by this

agency on November 28, 1978 that provided for the deduction is hereby

rescinded.

E. Other Issues

Relative vs. Minimum Strength

Several comments on NHTSA's ANPRM of June 19, 1987 suggested that

NHTSA replace the present relative body joint strength requirement (60

percent of the tensile strength of the weakest joined body panel) with

an absolute minimum strength requirement. Specifically, Thomas

suggested that the minimum required joint strength for interior body

panels be established at 60 percent of the strength of 22 gauge steel,

with a minimum tensile strength of 3,103 mPa (45,000 psi). For exterior

body panels, Thomas suggested that the requirement be based on 20 gauge

steel. The State of Connecticut suggested that a minimum strength

requirement be based on materials currently used in school buses that

performed favorably relative to those that performed poorly in similar

crashes studied by the NTSB. The National Association of State

Directors of Pupil Transportation suggested that minimum strength

requirements be based on 60 percent of the tensile strength of 18 gauge

steel for exterior panels and 20 gauge steel for interior panels,

regardless of the materials used. Ford suggested that NHTSA include a

minimum strength requirement as an optional alternative to the present

relative strength requirement. NHTSA tentatively determined that the

standard should be amended to establish a minimum strength standard,

but requested comments in the NPRM on the issue.

NHTSA received comments on both sides of this issue. Those favoring

establishment of a minimum strength requirement generally agreed that

all school buses, regardless of size, should be subject to the same

body panel joint strength requirements. Thomas disagreed with the

proposal to base a minimum strength requirement on 18 and 20 gauge

steel, contending that 20 and 22 gauge steel would suffice. Connecticut

agreed with Thomas, but disagreed with Ford's suggestion to make an

absolute strength standard optional. The West Virginia Department

[[Page 59738]]

of Education urged adoption of the recommendation of the National

Standards Committee of the 11th National Conference on School

Transportation which met in May 1990. That committee recommended that

school bus body panels be constructed of prime commercial quality steel

or other metal or material with strength at least equivalent to all-

steel, as certified by the manufacturer. The Maryland Departments of

Education and Motor Vehicles believed it appropriate to establish a

minimum absolute joint strength standard which allows for equivalent

strength materials. SPI and the CDE favored basing an absolute strength

standard on 18 and 20 gauge steel for external and internal body panels

respectively, while the CHP favored a standard governing the minimum

strength for the weaker component of each joint, thus preventing the

manufacturer from deliberately selecting body panel materials of low

tensile strength.

Collins, Blue Bird and MCSSB opposed the proposal to set an

absolute minimum strength standard. Collins asserted that the relative

strength standard makes the most sense, insofar as the joint strength

requirements must be consistent with the parent materials being joined,

the expected loads, the probability of occurrence, and the location of

the joint. Blue Bird argued that the proposal was neither practical nor

objective and stated that some state specifications contain design and

performance standards that require manufacturers to provide specific

gauges and thicknesses of material for most body components. MCSSB

asserted that the relative strength standard is preferable to the

absolute standard in that the relative standard provides greater

flexibility in material usage and methods which will increase strength.

To set an absolute minimum requirement would restrict future

developments.

NHTSA carefully considered the comments on this issue and was

persuaded by the comments of Collins, Blue Bird, and MCSSB that body

panel joint strength should be consistent with the bus manufacturers'

choice of body panel materials. School bus manufacturers currently

utilize many different thicknesses, or gauges, of steel in constructing

their bus bodies, depending on the type and location of the joints.

Thicknesses of panels and structural components range from 0.9

millimeters (0.034 inches) to 16 millimeters (.625 inches). Lastly, a

minimum standard based on steel gauge would force manufacturers to

overdesign their lightly loaded joints, requiring costly new tooling.

Many school bus manufacturers are small business entities. Having to

build to the heaviest loaded joint or the thickest gauge, somewhere

between 18 and 22 gauge steel as suggested by commenters, would result

in increases in vehicle weight, manufacturing costs, and operating

costs with little or no corresponding increases in school bus safety

benefits. Therefore, specifying a minimum absolute strength requirement

by specifying a minimum steel gauge would be design restrictive and

require significant changes in current industry design practices and

procedures.

Some commenters expressed concern that under the relative strength

approach, a manufacturer could deliberately select weak materials, thus

lowering overall joint strength and reduce the number of fasteners

needed for assembly. This has not happened under standard industry

practices, however, and this agency has noted no degradation of safety

attributable to the relative strength requirement. In its Safety Study:

Crashworthiness of Large Poststandard School Buses, March 18, 1987, the

NTSB found that large school buses with body panel joints that complied

with the standard maintained structural integrity very well, even in

severe crashes, thus providing effective protection to school bus

occupants. Accordingly, NHTSA perceives no safety basis for changing

the current relative strength standard in favor of an absolute minimum

standard.

Effective Date

49 U.S.C. 30111(d) provides that a standard may not become

effective before the 180th day or later than one year after the

standard is prescribed, except upon a finding that a longer or shorter

lead time is in the public interest. The NPRM proposed an effective

date of 18 months after date of publication in the Federal Register for

this final rule. None of the commenters addressed that issue.

As pointed out above, many if not all small school bus

manufacturers currently offer, as an option, small school buses with

body panel joints that comply with Standard No. 221 to accommodate

those 21 states and the District of Columbia that require such

compliance. The agency believes, therefore, that at least some of the

tooling needed to comply with the changes mandated by this final rule

is already in place. Nevertheless, some additional tooling may be

required for all small school buses to be produced in compliance with

Standard No. 221. In addition, MAPs in both large and small school

buses may require redesign and testing in order to meet the new

requirements. Accordingly, NHTSA believes that 18 months is sufficient

lead time for manufacturers to accomplish any necessary redesign,

retooling, testing, and marketing strategy to meet the requirements

promulgated by this final rule, and that the 18 month lead time is

therefore in the public interest.

IV. Rulemaking Analyses and Notices

A. Executive Order 12866, Regulatory Planning and Review, and DOT

Regulatory Policies and Procedures

NHTSA has evaluated the impacts of this final rule and has

determined that it is significant within the meaning of the Department

of Transportation's regulatory policies and procedures. This rule was

reviewed under E.O. 12866.

The agency has prepared a Final Regulatory Evaluation (FRE) for

this rulemaking action and has placed a copy of that FRE in the public

docket. A copy of the FRE may be obtained by contacting the

Department's Docket at the address given at the beginning of this

document.

As explained in the FRE, NHTSA estimates that the average consumer

cost per vehicle affected by this final rule will be approximately $221

per large school bus and $343 per small school bus. Those retail price

increases include variable costs, fixed factory overhead, tooling, and

manufacturers' and dealers' profit margins. The difference in cost

between large and small buses arises from the fact that large school

buses, which already comply with the body panel joint strength

standards of Standard 221, have only to bring their MAPs into

compliance. Small school buses, on the other hand, which have

heretofore been excluded from the joint strength requirements of

Standard 221, must bring their body panel joints and their MAPs into

compliance.

Information available to NHTSA indicates that the average combined

total of annual sales of large and small school buses is approximately

35,000 units. Approximately 84 percent of those are large and 16

percent are small.

The estimated costs for small school buses were derived as follows.

As discussed above, 21 states and the District of Columbia currently

require small school buses to comply with the joint strength

requirements of Standard No. 221. Sales within those jurisdictions

represent 35 percent of small school bus sales. NHTSA estimates that

the average cost of bringing body panel joints on 65 percent (@($414)

joint strength upgrade) of the small school buses and MAPs on 100

percent (@($74) MAP redesign) of

[[Page 59739]]

the small school buses into compliance with Standard No. 221 will be

$343 per vehicle. (.65($414)+1.00($74)=$343.) The total annual consumer

cost for implementing the terms of this final rule for small school

buses, therefore, is estimated to be $1,920,800. ($343 x 16% of 35,000

school buses.) These costs are based on optional equipment costs and

may be overstated when required on all vehicles.

As noted above, the agency estimates that the average cost per

large school bus will be $222. Thus, the total annual consumer cost of

limiting the MAP exclusion in large school buses would average

approximately $6,526,800 ($222 x 84% of 35,000 school buses).

The total annual consumer cost to implement the amendments

promulgated by this final rule for both large and small school buses is

estimated to be $8,447,600.

NHTSA believes that this rule will reduce 6 to 46 minor to serious

injuries (AIS 1-3) annually. It is estimated that 5 to 33 AIS 1-3

laceration-type injuries will be reduced on large school buses due to

the narrowing of the MAPs requirements. It is also estimated that the

injury reduction for small school buses will be 0 to 3 AIS 1-3

laceration-type injuries and 1 to 10 AIS-3 fracture-type injuries. The

methodology used to obtain these benefits can be found in the Final

Regulatory Evaluation available in the docket.

B. Regulatory Flexibility Act

NHTSA has also considered the impacts of this final rule under the

Regulatory Flexibility Act. NHTSA's analysis appears in the FRE. Based

on such evaluation, I certify that the amendments will not have a

significant economic impact on a substantial number of small entities.

The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires

each agency to evaluate the potential effects of its rules on small

businesses, small organizations, and small governmental jurisdictions.

The small businesses and organizations most likely to be affected by

this final rule are: (1) School bus manufacturers; (2) school bus

dealers and distributors; and (3) public and private school bus

transportation owners and operators.

The Small Business Administration (SBA) defines a bus manufacturer

with less than 500 employees as a small business (13 CFR part 121).

Using that definition, the agency believes that many of the school bus

manufacturers qualify as small businesses. As discussed above, most bus

manufacturers known by NHTSA to build small school buses currently

offer small school buses with complying body panel joints as an option.

The manufacturers produce these vehicles to accommodate the 21 states

and the District of Columbia which require that all school buses comply

with Standard No. 221. NHTSA believes, therefore, that no new

manufacturing techniques or tooling will be required by school bus

manufacturers in order to build school buses that comply with the

requirements of Standard No. 221. Further, costs, as a percentage of

the total school bus manufacturing cost, will not increase

significantly. Thus, any impact on total school bus sales will be

negligible. On balance, the agency anticipates little measurable impact

on school bus manufacturers' revenue levels, profitability, or

employment.

The SBA defines a motor vehicle retailer with less than $11,500,000

in annual receipts as a small business. There are approximately 465

school bus dealers and distributors in the United States. Over the past

6 years (1991-1996), an annual average of approximately 35,000 school

buses were sold, representing an average of 75 buses per dealer. In

order to reach the threshold of $11,500,000 in annual sales receipts,

the average dealer would have to sell a much larger number (270) of

large school buses annually, assuming a cost of $45,280 per unit. Thus,

most school bus dealers are probably small businesses. Because of the

negligible cost impact on manufacturers, the agency also anticipates

little measurable impact on retailers' revenue levels, profitability,

or employment.

School bus operators will probably be the group most affected by

the amendments to Standard No. 221 set forth in this final rule because

of increased school bus purchase prices as discussed above, and

possibly increased maintenance costs. The modest increase in purchase

prices is not expected to influence significantly the demand for new

school bus products. The sales weighted average consumer cost increase

of $222 for large school buses is 0.49 percent of the price of a new 66

passenger school bus with an approximate $45,280 retail purchase price.

For small school buses, the estimated incremental consumer cost of $343

per affected vehicle represents 1.21 percent of the retail price of a

new $28,300 small school bus.

It is difficult to predict what impact the projected retail price

increases discussed above will have on school bus purchases by states

and/or school districts. There is a strong and continuing demand for

school buses to transport school children and no alternative to the

purchase of those vehicles. On the one hand, for many states and school

districts operating on tight budgets, a 1.21 percent rise in the prices

of small school buses and a 0.49 percent increase in the prices of

large school buses may result in a proportionate reduction in new

school bus sales. On the other hand, school districts may offset price

increases by purchasing school buses with less optional equipment, such

as luggage racks, extra batteries, or upgraded interiors. Even assuming

the ``tight budget'' scenario, the agency believes that new school bus

sales revenues will remain relatively constant. Thus, the net impact on

school bus production and sales should be negligible.

C. Paperwork Reduction Act

In accordance with the Paperwork Reduction Act (44 U.S.C. 3501 et

seq.), the agency notes that there are no collection of information

requirements associated with this final rule.

D. National Environmental Policy Act

NHTSA has analyzed this final rule 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.

E. Executive Order 12612, Federalism

NHTSA has analyzed this final rule in accordance with the

principles and criteria contained in Executive Order 12612, Federalism,

and has determined that this final rule has borderline federalism

implications. The agency's initial determination, however, is that such

implications are not sufficient to warrant preparation of a Federalism

Assessment.

F. Civil Justice Reform

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

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

effect, a state or political subdivision may prescribe or continue in

effect a standard applicable to the same aspect of performance of a

motor vehicle only if the standard is identical to the Federal

standard. However, the United States Government, a state or political

subdivision of a state may prescribe a standard for a motor vehicle or

motor vehicle equipment obtained for its own use that imposes a higher

performance requirement than that required by the Federal standard. 49

U.S.C. 30161 sets forth a procedure for judicial review of final rules

establishing, amending or revoking Federal motor vehicle safety

standards. A petition for reconsideration

[[Page 59740]]

or other administrative proceedings is not required before parties may

file suit in court.

List of Subjects in 49 CFR Part 571

Motor vehicle safety, Reporting and recordkeeping requirements,

Tires.

In consideration of the foregoing, 49 CFR 571.221 is amended as

follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

follows:

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

delegations of authority at 49 CFR 1.50.

2. Standard No. 221 is amended by revising S3; revising the

definitions of ``body panel joint'' and ``bus body'' in S4; adding, in

alphabetical order, the definitions of ``maintenance access panel,''

``passenger compartment'' and ``serviceable component'' to S4; and

revising S5 and S6, to read as follows:

Sec. 571.221 Standard No. 221, School Bus Body Joint Strength.

* * * * *

S3. Application. This standard applies to school buses.

S4. Definitions.

* * * * *

Body panel joint means the area of contact or close proximity

between the edges of a body panel and another body component, including

but not limited to floor panels, and body panels made of composite

materials such as plastic or plywood.

Bus body means that portion of a bus that encloses the bus occupant

space, including the floor and firewall (the body panel separating the

engine compartment from the occupant space), but excluding the bumpers

and chassis frame and any structure forward of the forwardmost point of

the windshield mounting.

* * * * *

Maintenance access panel means a body panel which must be moved or

removed to provide access to one or more serviceable component(s).

Passenger compartment means space within the school bus interior

that is between a vertical transverse plane located 762 mm in front of

the forwardmost passenger seating reference point and including a

vertical transverse plane tangent to the rear interior wall of the bus

at the vehicle centerline.

Serviceable component means any part of the bus, of either a

mechanical or electrical nature, which is explicitly identified by the

bus chassis and/or body manufacturer in the owner's manual or factory

service manual as requiring routine maintenance actions at intervals of

one year or less. Tubing, wires and harnesses are considered to be

serviceable components only at their attachments.

S5. Requirements.

S5.1 Except as provided in S5.2, each body panel joint shall meet

S5.1.1 and S5.1.2.

S5.1.1 Body panels attached to each other shall have no unattached

segment at the joint longer than 203 mm.

S5.1.2 When tested in accordance with the procedure of S6, each

body panel joint shall hold each body panel to the component to which

it is joined when subjected to a force that equates to 60 percent of

the tensile strength of the weakest joined body panel, determined

pursuant to S6.2.

S5.2 Exclusions.

S5.2.1 The requirements of S5.1.1 and S5.1.2 do not apply to--

(a) Any interior maintenance access panel which lies forward of the

passenger compartment, or, which exceeds 305 mm when measured across

any two points diametrically on opposite sides of the opening.

(b) Trim and decorative parts which do not contribute to the

strength of the joint, support members such as rub rails which are

entirely outside of body panels, doors and windows, ventilation panels,

and engine access covers.

S5.2.2 The requirements of S5.1.2 do not apply to joints from

which a test specimen of the dimensions specified in Figure 1 can not

be obtained.

S6 Procedure.

S6.1 Preparation of the test specimen.

S6.1.1 If a body panel joint is 203 mm long or longer, cut a test

specimen that consists of any 203 mm segment of the joint, together

with a portion of the bus body whose dimensions are those specified in

Figure 1, so that the specimen's centerline is perpendicular to the

joint at the midpoint of the joint segment. Where the body panel joint

is not fastened continuously, select the segment so that it does not

bisect a spot weld or a discrete fastener. Support members which

contribute to the strength of a body panel joint, such as rub rails on

the outside of body panels or underlying structure attached to joint

members, shall remain attached to the test specimen, except that

material may be removed from the support members as necessary to clear

the gripping areas of the joint members being tested.

S6.1.2 [Reserved]

S6.1.3 Prepare the test specimen in accordance with the

preparation procedures specified in the 1989 edition of the Annual Book

of American Society for Testing and Materials (ASTM) Standards.

S6.2 Determination of minimum allowable strength. For purposes of

determining the minimum allowable joint strength, determine the tensile

strengths of the joined body components as follows:

(a) If the mechanical properties of a joint component material are

specified by the ASTM in the 1989 Annual Book of ASTM Standards, the

lowest value of that material's tensile strength per unit of area shown

in that source shall be used.

(b) If the mechanical properties of a material are not specified by

the ASTM in the 1989 Annual Book of ASTM Standards, determine its

tensile strength by cutting a sheet specimen from outside the joint

region of the bus body in accordance with Figure 1 of E 8-89 Standard

Test Methods of Tension Testing of Metallic Materials, in Volume 03.01

of the 1989 Annual Book of ASTM Standards, and by testing it in

accordance with S6.3.

(c) The cross sectional area of material removed to facilitate the

installation of fasteners shall be used in the determination of the

tensile strength of the weakest joined body panel.

S6.3 Strength test.

S6.3.1 The joint specimen is gripped on opposite sides of the

joint in a tension testing machine in accordance with the 1989 Annual

Book of ASTM Standards.

S6.3.2 Adjust the testing machine grips so that the applied force

on the joint is at 90 degrees plus or minus 3 degrees from the joint

centerline, as shown in Figure 1.

S6.3.3 A tensile force is applied to the specimen by separating

the heads of the testing machine at any uniform rate not less than 3 mm

and not more than 10 mm per minute until the specimen separates.

3. Figure 1 is revised to read as follows:

BILLING CODE 4910-59-P

[[Page 59741]]

[GRAPHIC] [TIFF OMITTED] TR05NO98.000

BILLING CODE 4910-59-C

Issued: October 29, 1998.

Ricardo Martinez,

Administrator.

[FR Doc. 98-29536 Filed 11-4-98; 8:45 am]

BILLING CODE 4910-59-P