The National Highway Traffic Safety Administration (NHTSA) published an Advanced Notice of Proposed Rulemaking (ANPRM) in the July 16, 2024 Federal Register (F.R. Vol. 89, No. 136; NHTSA-2024-0001). This ANPRM addresses petitions submitted for earlier rulemaking and includes proposals to revise FMVSS 207 Seating Systems. This NHTSA action fulfills the statutory mandate in Section 24204 of the Infrastructure Investment and Jobs Act (IIJA), which directed the Secretary of Transportation to issue an ANPRM to update FMVSS 207 Seating Systems.
This ANPRM partially grants petitions submitted by Environmental Research and Safety Technologists (ERST) and by ARCCA, Inc. These petitions sought changes to the FMVSS which increase the strength requirements for seat backs in the front row which the petitioners claim would improve the safety of children for deformation of seat backs in rear impacts. As part of the effort to facilitate further research and data development to support a potential rulemaking to update FMVSS 207, the NHTSA grants in part, petitions updating the moment strength requirement in FMVSS 207, the development of updated static and dynamic test procedures for seat back strength, and a request on structural symmetry. The request to restore pelvic restraint language to FMVSS 209, to add a rear impact test to FMVSS 213, and to add a cargo test and requirement to FMVSS 207 are denied. Also denied is a petition from the Center for Auto Safety (CAS) which stated that under the current standard, in certain higher speed rear end crashes, a seat could yield to the point that the seat becomes fully reclined. This condition may cause a belted occupant in the front seat to slide underneath the seat belt, leading to ejection into the rear seat space or outside the vehicle. They requested the addition of warning language to child restraint system labels and owner's manuals to warn parents against placing a child behind an occupied front seat. The NHTSA seeks comment on these issues.
The NHTSA continues to indicate that they believe in a unified approach to rear impact protection. The Agency has stated four categories of performance issues that need to be addressed as part of future changes to FMVSS 207. These include:
- Seating system integrity
- Seat energy absorbing capability
- Compatibility of a seat and its head restraint
- Seat and seat belt working together
The four rear impact protection categories indicate the need to maintain a balance between energy absorbing and stiffness characteristics. The research indicates that the severity and type of occupant injuries varies with impact velocity in rear collisions. Low-to-moderate velocity crashes represent the majority of rear collisions, and are responsible for the majority of reported injuries (mainly whiplash). At higher impact velocities the injury risks for the occupant of a seat include bodily impact with vehicular structures, severe thorax, pelvis, and neck injuries, and other risks. At higher impact velocities, deformation of the seat sufficient to allow interaction between front and rear occupant rows and associated injuries can occur.
The NHTSA seeks comment broadly on an update to the FMVSS’s regarding occupant protection in rear impacts. Even though it has been clear for many years that the ideal approach to rear impact safety would incorporate consideration of both moderate and severe rear impacts, is there a sound scientific basis for a reasonable update to the FMVSS’s for rear impact protection and are the necessary technical tools available for a sound rulemaking proposal?
FMVSS 207 establishes requirements for seats, seat attachment assemblies, and their installation in passenger cars, multipurpose passenger vehicles, trucks designed to carry at least one person, and buses. FMVSS 207 sets minimum requirements for the strength of the seat back and its associated restraining devices and adjusters. The testing specifies an application of a rearward force on the uppermost cross member of the seat back structure that results in a moment applied to the attachment (often the recliner mechanism) of the seat back and the remainder of the seat structure. Although FMVSS 207 sets the minimum seat back strength requirement, since 1968 the de facto minimum requirement for seat back strength has effectively been set by FMVSS 202/202a Head Restraints.
The main areas covered by the ANPRM include:
- Safety problem in rear impact occupant protection
- Regulatory and research history of seat backs
- Summary of literature review to provide context for the ANPRM
- Discussion of the submitted petitions
- Description of the unified approach with regard to FMVSS 207 and FMVSS 202a, and the NHTSA’s research efforts in this area along with the knowledge gaps that may need to be filled prior to implementing this unified approach
The NHTSA is pursuing research to gain a greater understanding of the modern rear impact protection issue which is regulated under FMVSS 207 and 202a. Recent rear impact field data is helpful to define the overall safety issue and determine whether any countermeasure to a problem is cost effective. This ANPRM discusses a two-tiered dynamic testing approach. NHTSA is pursuing sled testing of rear impacts to explore this dynamic approach and has conducted an initial exploratory series of high-speed rear impact tests. The NHTSA has ongoing research in rear impact sled testing using PMHS occupants that in turn supports an ATD based assessment of rear impact injuries and dynamics. A computational parametric study has also been proposed to broadly investigate rear impact dynamics and various protection measures. If a rulemaking is pursued, NHTSA will also perform research tasks to develop the necessary cost and benefit estimates for upgraded rear impact protection estimates. NHTSA expects this research to provide information to support future rulemaking decisions. Throughout the ANPRM the NHTSA asks for comment on some specific areas to determine what upgrade, if any, to FMVSS 207 (and FMVSS 202a) can meet the requirements of the Safety Act with the aim of improving occupant protection in rear impact collisions. The NHTSA also seeks comment on the overall approach proposed in the ANPRM. Would a greater impact be achieved if the Agency's resources were directed in another area of rear impact protection or more focused in a critical area?
Comments must be received no later than September 16, 2024. The ERST and ARCCA petitions are granted in part and the CAS petition is denied as of July 16, 2024.
The ANPRM is available on InterRegs.NET for our US Federal subscribers and is also available at Selectregs.