Interpretation ID: aiam2440
Crown Coach Corp.
2428 East 12th Street
Los Angeles
CA 90021;
Dear Mr. Hartman: This is in response to your letter of October 7, 1976, in which you as several questions concerning Standard No. 217, *Bus Window Retention and Release*, and Standard No. 222, *School Bus Passenger Seating and Crash Protection*.; Your first question asks whether a California regulation requirin 20-inch minimum seat spacing in school buses would be preempted by the requirement for 20-inch maximum seat spacing in Standard No. 222.; The National Traffic and Motor Vehicle Safety Act (the Act) provides i Section 103(d) that any state or local law or regulation on an aspect of motor vehicle performance covered by a Federal standard must be identical to that Federal standard. Although the NHTSA requirement is phrased in terms of maximum spacing while the California standard concerns minimum spacing, the aspect of performance in question is seat spacing. Therefore, it is the NHTSA's opinion that a California standard on seat spacing regulates the same aspect of performance and to the degree it is not identical to the Federal standard it would be preempted.; Your second question asks whether the seating reference point, a specified in relation to the H' Point used in SAE Standard J826b, varies with the size of different individuals. The seating reference point, as defined by the NHTSA in Part 571.3 allows the manufacturer some discretion in selecting a point that approximates the position of the pivot center of the human torso and the thigh. While the NHTSA definition does refer to the SAE procedures for H' point location that includes the specific measurements you cite, the manufacturer retains discretion to vary this point slightly as long as he can show that the point selected continues to simulate the position of the pivot center of the human torso and the thigh of the passengers for whom the seat is designed.; Finally, you note in your letter that compliance with the seat spacin required in Standard No. 222 might entail relocation of the side emergency exit, because Standard No. 217 requires that [a] vertical transverse plane tangent to the rearmost point of a seat back shall pass through the forward edge of a side emergency door.' The seat spacing requirement arguably could occasion the realignment of the side emergency door, but this does not have to be the case. The manufacturer is free to adjust seat spacing to be properly aligned with the emergency exit. The NHTSA's intent in this requirement is to provide an emergency exit opening extending at least 2 feet rearward of a vertical transverse plane tangent to the rearmost point of a seat back. The agency would not prohibit the use of doors wider than 2 feet as long as a minimum 2-foot opening is provided rearward of the reference plane and the latch mechanism is operated by a device located within the required 2-foot opening.; Sincerely, Frank Berndt, Acting Chief Counsel