On June 22, 2005 the National Highway Traffic Safety Administration (NHTSA) issued a Notice of Proposed Rulemaking (Docket No. NHTSA 2005-21600) that would amend the definition of "Designated Seating Position". NHTSA says that this proposed rule would also add a more objective method of determining the number of designated seating positions on bench and split-bench seats. The proposed rule would also revise test procedures for seat belt anchorage requirements so that they are suitable for side-facing, temporary or folding jump seats.
NHTSA says that this proposed revision will have the effect of eliminating real world use of non-designated seating positions. NHTSA also states that manufacturers could comply by redesigning their seats to include an appropriate impediment, provide the necessary void between adjacent seat cushions, or by installing an additional seat belt assembly. The agency anticipates that manufacturers would be more likely to redesign such seats, if needed, to incorporate an impediment or void as necessary.
This NPRM would establish a revised procedure for measuring hip room and to place it in a new section, Part 571.10, "Designation of Seating Positions". To accomplish this, NHTSA would use a modified version of SAE Recommended Practice J1100 rev. February 2001, "Motor Vehicle Dimensions" for measuring hip room. This section would also add a formula for calculating the number of designated seating positions which would be dependent on overall hip room. This formula would be used as follows: For seats with less than 1400 mm (55 inches), the measured hip room would be divided by 400 and the result rounded (up or down) to the nearest whole number. For seats with more than 1400 mm (55 inches), the measured hip room would be divided by 450 and the result rounded (up or down) to the nearest whole number.
NHTSA is also proposing to include auxiliary seats and jump seats in the definition of "designated seating position". Currently, the definition does not include these types of seats. Since these seats are not designated seating positions, they are not subject to the occupant crash protection requirements applicable to designated seating positions (e.g., safety belt requirements). Presently, the agency urges that all occupants in light vehicles be appropriately restrained when a motor vehicle is in operation. When the agency originally adopted the designated seating position definition, safety belt use rates were well below 20 percent and the focus of the agency was not on temporary seats. Now that safety belt use rates are much higher, the agency is focused on all occupants being properly restrained. This includes those occupants on auxiliary seats.
If this proposed definition is adopted, auxiliary seats and folding jump seats would also be required to meet all requirements in FMVSS's applicable to designated seating positions, including the requirements of FMVSS No. 210, "Seat Belt Assembly Anchorages". The current test procedures for the anchorage strength requirements as specified in S5.2 of FMVSS No. 210 were designed for forward and rear facing seats only. Under S5.2 of FMVSS No. 210, a force must be applied in the direction in which the seat faces in a plane parallel to the longitudinal centerline of the vehicle. For side-facing seats, including auxiliary or jump seats, the direction that the seat faces is perpendicular to the longitudinal centerline of the vehicle. Consequently, a force cannot be applied simultaneously in the direction that a side-facing seat faces and in a plane parallel to the longitudinal centerline of the vehicle. To permit strength testing of seat belt anchorages at side-facing designated seating positions, this NPRM is proposing to amend S5 of FMVSS No. 210 to specify that for side-facing seats, the specified force would be applied in the direction that the seat faces in a vertical plane perpendicular to the longitudinal centerline of the vehicle.
If adopted, the amendments proposed in this rulemaking action would become effective on the third September 1st after the date of publication of a final rule in the Federal Register. For example, if a final rule were adopted on December 1, 2005, the rule would be effective beginning September 1, 2008.
If you are interested in commenting on this NPRM, you should submit comments early enough to ensure that Docket Management receives them not later than August 22, 2005.