94-31739. Federal Motor Vehicle Safety Standards; Roof Crush Resistance  

  • [Federal Register Volume 59, Number 247 (Tuesday, December 27, 1994)]
    [Unknown Section]
    [Page 0]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 94-31739]
    
    
    [[Page Unknown]]
    
    [Federal Register: December 27, 1994]
    
    
    -----------------------------------------------------------------------
    
    DEPARTMENT OF TRANSPORTATION
    National Highway Traffic Safety Administration
    
    49 CFR Part 571
    
    [Docket No. 94-97; Notice 01]
    RIN 2127-AF40
    
     
    
    Federal Motor Vehicle Safety Standards; Roof Crush Resistance
    
    AGENCY: National Highway Traffic Safety Administration (NHTSA) DOT.
    
    ACTION: Request for comments.
    
    -----------------------------------------------------------------------
    
    SUMMARY: Ford Motor Company (Ford) and the Recreation Vehicle Industry 
    Association (RVIA) have each submitted petitions asking NHTSA to 
    clarify some provisions in the roof crush resistance standard. 
    Specifically, both these petitioners suggested changes to the current 
    specifications for placing the load plate on vehicles during compliance 
    testing, particularly vehicles with sloped aerodynamic roofs or raised 
    roofs. NHTSA has granted both of these petitions.
        This notice asks the public for its views and comments on what 
    changes, if any, are needed to the roof crush resistance standard. 
    NHTSA will consider all such comments together with the petitions in 
    deciding what regulatory changes, if any, may be appropriate for the 
    roof crush resistance standard.
    
    DATES: Comments on this notice must be received by NHTSA no later than 
    February 10, 1995.
    
    ADDRESSES: Comments should refer to the docket and notice number shown 
    in the heading of this notice and be submitted to: NHTSA Docket 
    Section, Room 5109, 400 Seventh Street, SW., Washington, DC 20590. 
    Docket hours are 9:30 a.m. to 4 p.m. Monday through Friday.
    
    FOR FURTHER INFORMATION CONTACT:
    Dr. Glen Rains, Office of Vehicle Safety Standards, NRM-14, NHTSA, 400 
    Seventh Street, SW., Washington, DC 20590. Dr. Rains can be reached by 
    telephone at (202) 366-5277.
    
    SUPPLEMENTARY INFORMATION:
    
    Background
    
        Standard No. 216 (49 CFR 571.216) sets forth roof crush resistance 
    requirements that must be met by passenger cars, trucks, buses, and 
    multipurpose passenger vehicles with a GVWR of 6000 pounds or less. The 
    purpose of the standard, as stated in S2 of the standard, is ``to 
    reduce deaths and injuries due to the crushing of the roof into the 
    passenger compartment in rollover accidents.''
        Standard No. 216 seeks to achieve this purpose by requiring 
    vehicles to be certified as complying with a performance test in which 
    a load of 1\1/2\ times the unloaded vehicle weight (up to a maximum of 
    5000 pounds for passenger cars) is applied to the vehicle roof by means 
    of a rigid unyielding block whose lower surface consists of a flat 
    rectangle 30 inches wide and 72 inches long.
        During the test, the plate is required to be positioned so that:
        (1) When viewed from the side of the test vehicle, the test plate 
    is angled 5 deg. toward the front of the vehicle;
        (2) When viewed from the front of the test vehicle, the test plate 
    is angled 25 deg. below the horizontal on the side of the vehicle to 
    which the test plate is applied; and
        (3) The initial contact point of the test plate with the test 
    vehicle roof is 10 inches from the forwardmost point of the test plate.
        The test plate orientation and placement are illustrated in Figure 
    1 of Standard No. 216.
        These requirements were initially proposed in a notice published on 
    January 6, 1971 (36 FR 3) and are patterned after the specifications in 
    the Society of Automotive Engineers (SAE) Standard J374. At that time, 
    most vehicle roofs were less rounded than today's designs, and there 
    were no raised-roof vehicles to be tested. Thus, the specifications for 
    positioning the test plate ensured that it would be positioned to 
    measure the roof's strength in the A-pillar region and to ensure that 
    the strength was sufficient to prevent sudden collapse of the roof 
    above the A-pillars and front seating areas during rollovers.
    
    Petitions
    
    A. RVIA
    
        RVIA recently submitted a petition asking that vans, motor homes 
    and other multipurpose passenger vehicles, trucks, and buses that have 
    raised roofs and that are now subject to Standard No. 216 be tested 
    according to the requirements of Standard No. 220, School Bus Rollover 
    Protection. Standard No. 220 subjects vehicles to the same force on the 
    roof as does Standard No. 216 (1\1/2\ times the unloaded vehicle 
    weight), but the force is applied differently. The test plate used in 
    Standard No. 220 is larger than the 30 x 72 inch plate used in Standard 
    No. 216. In addition, instead of concentrating the load in the vicinity 
    of the A-pillars the test load is evenly distributed over the entire 
    roof in Standard No. 220.
        RVIA used the following arguments to support its petition:
        (1) There are several van conversions currently produced with 
    raised roofs that are subject to Standard No. 216. Such vehicles 
    include conversions of the Plymouth Voyager, Doge Caravan, Chrysler 
    Town & Country, Chevrolet Astro, and GMC Safari minivans. Because of 
    the raised roof configuration, the load plate for the test cannot be 
    placed according to the specified procedure in the standard.
        (2) Since the original vehicles, prior to conversion that raises 
    the roof, have been certified as complying with Standard No. 216, the 
    A-pillar strength will have already been demonstrated. Testing to 
    Standard No. 220 after raising the roof would then test the strength of 
    the entire roof structure.
    
    B. Ford
    
        Ford recently submitted a petition focused on what it believes is 
    an anomaly with the current positioning procedures for the test plate 
    in Standard No. 216. Ford indicated that several of its models with 
    aerodynamic roof designs have roof slopes greater than 5 deg. at the 
    forward edge of the roof. The test plate is required to be angled 
    5 deg. of the forward edge of the roof. The effect of the slope on 
    these aerodynamic roof designs is that the initial point of contact 
    between the roof and the test plate is moved several inches behind the 
    A-pillar when the test plate is positioned according to the current 
    placement procedure. Ford believes this rearward movement of the 
    initial contact point is contrary to the agency's intent when it 
    initially promulgated the standard.
        Ford argued that additional support for this argument can be found 
    in S6.2 of Standard No. 216, which specifies the test plate should be 
    applied by ``(o)rient(ing) the test device as shown in Figure 1 * * *'' 
    Figure 1 clearly shows the test plate is applied at the front corner of 
    the roof. Thus, for vehicles with sloped, aerodynamic roofs, there is a 
    conflict between Figure 1, which positions the test plate forward of 
    the leading edge of the roof, and S6.2(d), which specifies that the 
    test plate should be positioned with reference to the initial point of 
    contact, even if that point is rearward of the leading edge of the 
    roof. Ford acknowledged that NHTSA has addressed this conflict in an 
    October 3, 1980 interpretation, in which the agency said that the 
    language of S6.2(d) should be used to position the test plate, even if 
    that means the test plate will not be forward of the A-pillar or the 
    roof's leading edge. Ford indicated that it has followed this 
    interpretation, but it does not believe that such an interpretation 
    results in improved roof crush performance when vehicles are in use on 
    the public roads.
        Ford asked in its petition that S6.2(d) of Standard No. 216 be 
    amended to specify that the leading edge of the test plate should 
    always be placed over the leading edge of the vehicle roof. Ford 
    proposed the following language:
    
        The initial contact point, or center of the initial contact 
    area, is on the longitudinal centerline of the device. A plane 
    perpendicular to the lower surface of the test device and 25 mm 
    rearward of the front edge of the lower surface passes through the 
    rearmost point of the opening in the body structure for the 
    windshield.
    
    Agency Response to the Petitions
    
        NHTSA believes that both of these petitions raise issues that 
    should be examined further. RVIA believes the requirement to move the 
    test plate rearward of the A-pillar on conversion vans with raised 
    roofs imposes needless and significant burdens on second-stage 
    manufacturers. Ford believes the requirement to move the test plate 
    rearward of the A-pillar on vehicles with aerodynamic roofs is contrary 
    to the agency's original intent and results in a less stringent test of 
    the A-pillars' strength. both of these are relevant issues. 
    Accordingly, the agency has granted both the RVIA and Ford petitions. 
    NHTSA is now conducting a research program to investigate the test 
    methods described in these petitions and to see if the current test 
    procedures are suitable for vehicles with raised or contour roofs, or 
    if some changed test procedures are needed.
        The fact that the agency has granted these petitions does not mean 
    that the requirements of the standard will necessarily be modified. 
    NHTSA has undertaken to investigate this issue more carefully and, 
    after the conclusion of this investigation, will decide whether it 
    should propose any modifications to the test procedure. In the 
    meantime, manufacturers must continue to certify their vehicles for 
    compliance according to the existing requirements of Standard No. 216 
    unless and until some modified requirements are in place.
        Further, the fact that the agency has granted these petitions does 
    not mean that NHTSA agrees with all that is said in these petitions. 
    For instance, the RVIA petition asks that Standard No. 220 test for 
    roof crush resistance be substituted for the current Standard No. 216 
    test for roof crush resistance. NHTSA is concerned that such a 
    substitution could result in a less stringent test over the front 
    seating positions, or may not be appropriate to evaluate the strength 
    of the pillars for crush resistance. Standard No. 220 was developed for 
    school buses and it assesses the roof crush protection afforded for the 
    entire seating area. It does this by using a test procedure that loads 
    the entire roof structure, including A-, B-, and any other pillars in 
    the vehicle.
        By way of contrast, Standard No. 216 is applicable to smaller 
    vehicles. Front seat occupants experience the vast majority of deaths 
    and injuries in these vehicles. To address this, a test procedure was 
    developed to assess the roof crush protection afforded to front seat 
    occupants. The test procedure concentrates the load in the vicinity of 
    one of the A-pillars to simulate the most severe impact condition that 
    a pillar would experience in a rollover crash.
        It appears, then, that substituting the Standard No. 220 test for 
    raised roof vehicles instead of the Standard No. 216 test, would trade 
    off increased roof crush protection for rear seat occupants in those 
    vehicles, with diminished protection for front seat occupants. However, 
    there is no supporting information in the RIVA petition that quantifies 
    either how much protection front seat occupants might lose or how much 
    protection rear seat occupants might gain from this substitution. The 
    agency will examine this carefully in its research before deciding 
    whether to consider any change to the current test requirements.
        In addition, RVIA suggested that the strength of the A-pillars in 
    the vehicle that is converted by its members would be demonstrated by 
    the original vehicle manufacturer's certification for the vehicle that 
    complied with Standard No. 216. The agency is not convinced at this 
    point that this conclusion is valid because the agency has no data to 
    prove or disprove that the roof strength in the area of the A-pillars 
    is affected by raised roof conversions. RVIA provided no such data in 
    its petition in support of their claim.
        In its petition, Ford did provide some test data, although they 
    were very limited. Ford provided roof crush test results for two 
    prototypes of a new vehicle design. In one, the test plate was 
    positioned according to the current Standard No. 216 procedures. In the 
    second, the front edge of the test plate was positioned 100 mm behind 
    the front corner of the roof (closer to the A-pillar structure). The 
    test results from the latter procedure produced a peak force that was 
    49 percent higher than the peak force produced using the current 
    positioning procedure, within 5 inches of crush. When following 
    Standard No. 216 test procedures, the test plate was positioned 150 mm 
    behind the windshield opening, completely missing the A-pillar and 
    leading edge of the roof.
        Ford's petition indicates that its proposed change to the language 
    of S6.2(d) would consistently locate the test place one inch forward of 
    the rearmost edge of the front windshield opening, thereby reducing 
    test variability and ensuring that the test plate is positioned ahead 
    of the roof's leading edge. NHTSA notes that while this would position 
    the test plate over the leading edge of the roof, it would not 
    necessarily load the roof at the rearmost windshield opening. Ford's 
    proposed change retained the same test plate angles currently specified 
    in Standard No. 216, which means the initial contact point for the test 
    plate on the roof would be the same as at present. In other words, it 
    appears to NHTSA that Ford's proposal would ensure the consistent 
    orientation of the test plate over the front of the roof, but would not 
    ensure that area of the roof would be tested. Further, the agency is 
    uncertain whether the proposed test plate positioning one inch forward 
    of the rearmost edge of the front windshield opening would be an 
    improved test for all vehicles with uncommon roof shapes or whether it 
    would reduce the stringency of the current test procedure.
    
    Areas in Which the Public's Ideas and Information Are Requested
    
        The agency is interested in comments on the changes requested in 
    both the Ford and RVIA petitions. Therefore, the agency is seeking from 
    all interested parties comments on the two proposals along with any 
    available test data to substantiate or refute those proposals. The 
    agency is also interested in other ways to accommodate aerodynamically 
    sloped and raised roof vehicles. For instance, should the angles at 
    which the test plate is applied and/or the size and shape of the test 
    plate itself be changed? If the plate size were reduced or if the plate 
    shape were changed to circular, the test plate could be placed over the 
    A-pillar region on raised roof vehicles.
        Standard No. 216 currently provides that the test plate shall be 
    angled 5 deg. toward the front of the vehicle, when viewed from the 
    side of the test vehicle. This angle could be changed sufficiently to 
    ensure the test plate would contact the A-pillar region, with the new 
    angle based on an analysis of real world crashes and roof geometries.
        The agency is also interested in any other approaches the public 
    might wish to suggest in this area. As always, the most helpful 
    comments will be those that set forth data to substantiate the position 
    taken in the comment. NHTSA would like to alert commenters that the 
    agency will not propose any changes to Standard No. 216 test procedures 
    until the agency is satisfied that data and analysis show the changes 
    will not reduce real world safety protection for vehicle occupants.
    
    Submission of Comments
    
        Interested persons are invited to submit comments in response to 
    this request for comments. It is requested but not required that 10 
    copies be submitted.
        All comments must not exceed 15 pages in length (49 CFR 553.21). 
    Necessary attachments may be appended to these submissions without 
    regard to the 15-page limit. This limitation is intended to encourage 
    commenters to state their positions and arguments concisely.
        If a commenter wishes to submit certain information under a claim 
    of confidentiality, three copies of the complete submission, including 
    purportedly confidential business information, should be submitted to 
    the NHTSA Chief Counsel, Room 5219, 400 Seventh Street, SW., Washington 
    DC 20590, and seven copies from which the purportedly confidential 
    information has been deleted should be submitted to the Docket Section 
    at the street address given above. A request for confidentiality should 
    be accompanied by a cover letter setting forth the information 
    specified in the agency's confidential business information regulation 
    (49 CFR part 512).
        Comments on this notice will be available for inspection in the 
    docket. NHTSA will continue to file relevant information as it becomes 
    available in the docket after the closing date. Those persons desiring 
    to be notified upon receipt of their written comments in the Docket 
    Section should enclose, in the envelope with their comments, a self-
    addressed stamped postcard. Upon receipt, the docket supervisor will 
    return the postcard by mail.
    
        Authority: 49 U.S.C. 30111, 30168, delegations of authority at 
    49 CFR 1.50 and 49 CFR 501.8.
    
        Issued on December 20, 1994.
    Barry Felrice,
    Associate Administrator for Rulemaking.
    [FR Doc. 94-31739 Filed 12-23-94; 8:45 am]
    BILLING CODE 4910-59-P-M
    
    
    

Document Information

Published:
12/27/1994
Department:
National Highway Traffic Safety Administration
Entry Type:
Uncategorized Document
Action:
Request for comments.
Document Number:
94-31739
Dates:
Comments on this notice must be received by NHTSA no later than February 10, 1995.
Pages:
0-0 (1 pages)
Docket Numbers:
Federal Register: December 27, 1994, Docket No. 94-97, Notice 01
RINs:
2127-AF40: Test Device Placement
RIN Links:
https://www.federalregister.gov/regulations/2127-AF40/test-device-placement
CFR: (1)
49 CFR 571