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Federal Motor Vehicle Safety Standards; Seating Systems

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National Highway Traffic Safety Administration (NHTSA), DOT.


Termination of rulemaking.


This notice terminates a rulemaking proceeding to amend Federal Motor Vehicle Safety Standard (FMVSS) No. 207, “Seating systems.” NHTSA is seeking to improve motor vehicle seat performance in rear impacts. The agency has conducted extensive physical testing of seat backs, computer modeling of seated occupants in rear impacts and dynamic testing of instrumented test dummies in vehicle seats. However, additional research and data analyses are needed to allow an informed decision on a rulemaking action in this area. Since the Semi-Annual Regulatory Agenda (Unified Agenda) is intended to provide the public with information on rulemaking actions to be taken in the next year or so, and since we do not anticipate being able to take rulemaking action in this area in that time frame, we are terminating rulemaking proceedings on this issue. Research into this area will continue as time and resources allow, particularly as it relates to the goal of unifying FMVSS No. 202, “Head restraints,” and FMVSS No. 207 into a single comprehensive rear impact protection standard.

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For non-legal issues: Louis Molino, Office of Crashworthiness Standards, NVS-112, National Highway Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 20590. Telephone (202) 366-1833. Fax: (202) 366-4329.

For legal issues: Eric Stas, Office of Chief Counsel, NCC-112, National Highway Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 20590. Telephone: (202) 366-2992. Fax: (202) 366-3820.

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Table of Contents

I. Background

II. Agency Activities

III. Agency Rationale for Terminating Rulemaking

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I. Background

The agency's rulemaking activity related to the upgrade of seat back strength dates back to 1974. On March 19, 1974, NHTSA published a Notice of Proposed Rulemaking (NPRM) for FMVSS No. 207 in the Federal Register (39 FR 10268).[1] The NPRM proposed to: (1) Extend applicability of FMVSS No. 202 to front seats in multipurpose passenger vehicles (MPVs) and light trucks, and bus driver seats manufactured after September 1, 1976; (2) establish barrier crash testing for cars, MPVs, and light trucks; and (3) consolidate FMVSS No. 202 with FMVSS No. 207 because of the relationship between head restraints and seats.

On March 16, 1978, NHTSA published a Federal Register notice [2] (43 FR 11100) that invited public comments on a draft plan for motor vehicle safety and fuel economy rulemaking over a five year period (1980-1984). It noted that there were 13 active dockets for which actions had not been completed because limited resources were directed toward higher priority actions, the magnitude of the problem was not large, or NHTSA was unable to adequately document the nature and extent of the problem, and the notice stated that the agency contemplated terminating those actions. The NPRM to upgrade FMVSS No. 207 and combine it with FMVSS No. 202 was among those 13 actions. On April 26, 1979, then-Administrator Claybrook signed and published the “Five Year Plan for Motor Vehicle and Fuel Economy Rulemaking, Calendar Years 1980-1984” which confirmed the termination of the rulemaking for the FMVSS No. 207 upgrade and FMVSS No. 202 consolidation. Since 1989, NHTSA has granted four petitions related to seating system performance in rear impacts.

Improving seating system performance is more complex than simply increasing the strength of the seat back. A proper balance in seat back strength and compatible interaction with head restraints and seat belts must be obtained to optimize injury mitigation. Comprehensive information needed to determine that proper balance is not available, although there has been work on pieces of the problem.

II. Agency Activities

To remedy this, the agency has funded and/or performed research related to the issue of seat performance in rear impacts as priorities and resources have allowed. For example, NHTSA funded the University of Virginia to perform seat computer modeling to assess how changes in seat design might affect occupant kinematics in rear impacts.[3] Similarly, EASi Engineering Inc., was awarded a multi-year contract to address design issues for an advanced seat.[4] One of the parameters it assessed under that contract was rear seat performance. The agency itself performed static tests on 25 different vehicle seat designs to determine their force deflection characteristics.[5] More recently, NHTSA has funded dynamic sled testing of seats and seat mock-ups in simulated rear impacts at the Johns Hopkins Applied Physics Laboratory.[6] [7] In addition, over the past several years, the agency has added extra instrumentation to the test dummies and seats in vehicles tested under the FMVSS No. 301 rear impact compliance test program.

Through these programs, as well as through the work of other researchers outside the agency, we have improved our understanding of how seat performance affects rear impact occupant protection. Part of that understanding relates to how head restraints and seat backs work together. This understanding helped to guide the agency in formulating its proposal to upgrade FMVSS No. 202 (66 FR 968). As the agency developed that proposal, we kept in mind that our eventual goal is to evaluate the performance of head restraints and seat backs as a single system to protect occupants, just as they work in the real world, instead of evaluating their performance separately as individual components.

III. Agency Rationale for Terminating Rulemaking

Although the agency has a better understanding of the issues associated with seat performance in rear impacts at various speeds, further studies are needed to allow NHTSA to develop a proposed upgrade to FMVSS No. 207 that will effectively balance seat back strength and interaction with other vehicle attributes.

In addition, it continues to be a challenge to assess the potential benefits of regulatory strategies for improving seat performance in higher speed rear impacts. Although there is anecdotal evidence of occupant injury due to poor seat performance resulting in occupant-to-occupant contact, contact with the vehicle interior, or even ejections, it remains a difficult task to assess the scope of this problem on a national level. According to the National Automotive Sampling System (NASS) Crashworthiness Data System (CDS), rear impacts represent about 8 percent of crashes severe enough to make it necessary for a vehicle to be towed from the crash scene. In comparison, frontal crashes represent 56 percent; side crashes, 26 percent; and rollover crashes, 8 percent (NASS annualized data 1992-2001). However, rear impacts cause less than two percent of moderate-to-severe injuries. Similarly, the Fatality Analysis Reporting System (FARS) shows that about 3 percent of all traffic crash fatalities involved occupants of vehicles struck in the rear (FARS annualized data 1998-2002). Thus, in comparison to other crash modes, there is considerably less data available to assess the potential benefits of upgrading FMVSS No. 207 for higher speed rear impacts. The problem associated with the relatively small number of moderate-to-severe injuries in rear impacts is compounded by the difficulty in determining the extent to which those injuries can be attributed to seat performance.

We have concluded that further study is needed to make a definitive determination of the relative merits of different potential rulemaking approaches in this area. Accordingly, we have decided that we should remove this rulemaking from the Semi-Annual Regulatory Agenda (Unified Agenda) because rulemaking action is not anticipated in the near future. However, the agency will continue to monitor issues related to rear impact protection, and specifically the performance of seats in this crash mode. Research into this area will continue as priorities allow, particularly as it relates to the goal of unifying FMVSS Nos. 202 and 207 into a single comprehensive rear impact protection standard.

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Authority: 49 U.S.C. 30162; delegations of authority at 49 CFR 1.50 and 49 CFR 501.8.

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Issued on: November 9, 2004.

Stephen R. Kratzke,

Associate Administrator for Rulemaking.

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1.  NHTSA Docket No. 74-13; Notice 1.

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2.  Docket No. 78-07; Notice 1.

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3.  Docket Management System NHTSA 1998-4064-24.

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4.  Docket Management System NHTSA 1998-4064-27.

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5.  Docket Management System NHTSA-1998-4064-26.

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6.  Kleinberger M, Voo LM, Merkle A, Bevan M, Chang S: The Role of Seatback and Head Restraint Design Parameters on Rear Impact Occupant Dynamics. Proceedings of 18th International Technical Conference on the Enhanced Safety of Vehicles, Paper #18ESV-000229, Nagoya, Japan, May 19-22, 2003.

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7.  Voo LM, Merkle A, Wright J, and Kleinberger, M: Effect of Head-Restraint Rigidity on Whiplash Injury Risk. Proceedings of 2004 SAE World Congress, Paper #2004-01-0332, Detroit, MI, March 8-11, 2004.

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[FR Doc. 04-25425 Filed 11-15-04; 8:45 am]