The National Highway Traffic Administration (NHTSA) published a Notice of Proposed Rulemaking (NPRM) in the August 4, 2026 Federal Register (F.R. Vol. 91, No. 148; NHTSA-2025-0051) which responded to Petitions for Reconsideration to the January 7, 2026 FMVSS 225 proposed Final Rule (FR) and addressed some technical corrections as well as test procedure clarifications.
The FMVSS 225 revisions are intended to improve ease-of-use of the lower and tether anchorages, resulting in correct usage of the child restraint systems.
Specifically, the proposal:
- Allows a 4-year phase-in
- Permits small volume manufacturers an extended compliance period
- Allows a 2-year extension of sunset for convertibles
- Denies the tether routing over adjustable or removable head restraints
- Denies the extension of vertical transverse plane measurement for lower anchorage markings
- Provides some technical corrections
- Provides some clarification of test procedures.
The NHTSA addresses each of the Petitions for Reconsideration and provides rationale for their proposed actions regarding FMVSS 225 requirements and test procedures.
The NHTSA explained in the January 2025 Final Rule that the intent of the phase-in schedule was to provide sufficient time for vehicle manufacturers to accommodate significant vehicle system changes into manufacturers' normal course of vehicle redesign. Providing an additional year to the phase-in schedule will allow manufacturers to meet the requirements of this Final Rule with minimal cost impacts consistent with the intent of the January 2025 Final Rule.
The NHTSA understands that Small Vehicle Manufacturers (SMVs) might need more time to make vehicle design changes and that such changes may trigger added to costs due to SVMs longer design cycles. Given the unique design cycles of SVMs, the NHTSA is proposing to eliminate the phase-in period to meet the updated requirements in FMVSS 225 and instead require all SVMs to comply by the proposed compliance date. The petitioner requested September 1, 2030 as the compliance date for SVMs, but because the NHTSA is proposing to grant the request and extend the phase-in period for non-SVMs by one year (2031), the NHTSA is proposing September 1, 2031 as the compliance date for SVMs, with no phase-in. This proposal is consistent with the general lead time concerns addressed in the January 7, 2025 Final Rule.
The FMVSS 225 standard established in 1999 excluded convertibles from having to provide tether anchorages in rear seating positions. This exclusion was created in response to comments that vehicle manufacturers have technical problems installing tether anchorages in convertibles because the vehicles have folding roofs, a stowage area behind the seat back for the top and its mechanism, and less rear seat space. The NHTSA agreed that many convertibles could have design problems and determined that it could not at that time readily separate those convertibles from those without technical problems.
The NHTSA proposes to extend the convertible sunset date of the tether anchorage exclusions until September 1, 2033. They understand that some convertibles may present unique design challenges and that these models might follow longer design cycles. The NHTSA tentatively concludes that extending the sunset date for the exemption for convertibles will help accomplish the Final Rule's intent of increasing tether availability and also minimizing costs. The NHTSA specifically requests comments on the proposal for the two-year extension of the sunset dates. The NHTSA also proposes to extend the sunset date of the exception for lower anchorages in rear designated seating positions where interference with the transmission or suspension components prevent the location of the lower anchorages anywhere in the specified zones in S5.1(e) of FMVSS 225. This provision mostly affects convertible vehicles and aligning the sunset dates for the exception of both the tether anchorages and the lower anchorages in convertibles will help streamline the design development of child restraint anchorage systems in these vehicles.
The NHTSA has tentatively decided to deny the request to allow routing the tether strap over adjustable or removable head restraints. The January 7, 2025 Final Rule already considered and responded to comments raising concerns that relocating tether anchorages might require tooling and manufacturing changes. In response to these comments, the NHTSA provided an extended lead time followed by a phase-in period to comply with the updated requirements so that those changes could be made during regular vehicle design updates to mitigate cost.
The NHTSA has also tentatively decided to deny the request to extend permissible vertical measurement to locate lower anchorage markings as unnecessary. The June 27, 2003 Final Rule is the source of the current requirements in S9.5.1. The agency changed the original requirement, which consisted of only a vertical placement distance for the marking (seat back), to one that also allowed a horizontal placement for the marking on the seat pan. In support of this decision, the NHTSA explained that these location requirements provide greater clarity in relation to where the markings should be while also permitting the markings to be located either on the seat back or the seat cushion, and thus allowing more flexibility to manufacturers with atypical seat designs. Though the NHTSA changed some of the allowable distances for the markings in the January 7, 2025, the Final Rule. The intent of the 2003 Final Rule was maintained. The 2025 Final Rule continues to permit markings to be placed on the seat back or the seat pan. The different allowable distances already provided by the Final Rule should provide flexibility to manufacturers with atypical seat designs in relation to where to place the lower anchorage markings.
- The NHTSA proposes to modify the regulatory text for both the current requirements (S9.5.1(a)(3)) and the updated requirements (S9.5.2(a)(3)) to clarify the permissible marking locations. The NHTSA is also proposing to amend Figure 19 to FMVSS 225 so that the "b" measurement is specified as a continuous interval (Figure 2) instead of broken into positive and negative segments.
The NHTSA is proposing to clarify the test procedure to position clearance angle tool in some vehicles. The NHTSA is not codifying this step in the regulatory text of FMVSS 225 because the agency believes it is more appropriate to include this detailed information in the test procedure to help entities understand how to position the pulley bridge in the required position to make the clearance angle measurement appropriately.
- The NHTSA denies the request to align or allow use of the IIHS clearance angle tool for measuring the clearance angle in FMVSS 225. The 2015 NPRM proposed using a clearance angle tool based on the IIHS tool and the NHTSA received comments expressing concerns about the repeatability and reproducibility of that tool's measurements. As explained in the January 2025 Final Rule, the NHTSA added a pulley bridge (with adjustable feet to make it level) to apply a 67N (15lbf) force vertically to remove the difficulty of applying the specified load manually and address concerns raised by the commenters.
- Additionally, various corrections and clarifications to regulatory text are proposed and explained in the NPRM.
NHTSA is seeking comment on all aspects of the NPRM. Anyone wishing to file comments to this NPRM must submit them by September 3, 2026.
The NPRM is available on InterRegs.NET for our US Federal subscribers and is also available at Selectregs.