Interpretation ID: nht93-3.12

DATE: April 22, 1993

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Kirk Brown -- Secretary, Illinois Department of Transportation

TITLE: None

ATTACHMT: Attached to letter dated 3-15-93 from Kirk Brown to John Womack (OCC 8442)

TEXT: This responds to your letter of March 15, 1993, inquiring "whether modifying the throttle controls on a school bus so that a short person can operate it would jeopardize the manufacturer's certification that a bus is in compliance with the Federal Motor Vehicle Safety Standards" (FMVSS's).

By way of background, the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S1381 ET SEQ.; Safety Act) authorizes NHTSA to issue FMVSS's that apply to the manufacture and sale of new motor vehicles and new items of motor vehicle equipment. NHTSA has exercised its authority under the Safety Act to establish Standard No. 124, ACCELERATOR CONTROL SYSTEMS (49 CFR Part 571.124). Standard No. 124 "establishes requirements for the return of a vehicle's throttle to the idle position when the driver removes the actuating force from the accelerator control." The Safety Act requires each vehicle manufacturer to certify that its vehicle complies with all applicable safety standards, including Standard No. 124. This certification process requires each manufacturer to determine in the exercise of due care that its products meet all applicable requirements.

If the throttle control or other equipment on the new school bus were modified by the bus manufacturer, the bus manufacturer must ensure that the vehicle meets all applicable FMVSS's, including Standard No. 124. If the throttle control or other equipment were modified on a new bus prior to its first sale, the person who modifies the vehicle would probably be an alterer of a previously certified motor vehicle. As an alterer, that person would be required to certify that, as altered, the vehicle continues to comply with all of the safety standards affected by the modification. (See 49 CFR S567.7.)

If the modification is made after the vehicle's first sale, the only NHTSA requirement that would affect the modification is the "render inoperative" prohibition in S108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides that:

No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard.

The "render inoperative" provision would prohibit a commercial business from modifying the throttle in a manner that would negatively affect the vehicle's compliance with Standard No. 124. If the throttle control was built up in a way that prevented the throttle from returning to idle when the driver removed his or her foot, it would violate the render inoperative prohibition.

You ask whether NHTSA could grant a waiver to allow a school bus company to modify the throttle control on its vehicles. The Safety Act provides that

NHTSA may by regulation exempt a person from the "render inoperative" prohibition if the agency determines that an exemption is consistent with motor vehicle safety and the purposes of the Act. Based on the information in your letter, we believe it would be unlikely that the agency would decide that an exemption is appropriate for any modification that would prevent the throttle from returning to idle. Such an exemption would increase the incidence of engine overspeed and the likelihood of possible crashes resulting from this condition. That the vehicle in question is a school bus makes the safety concerns even more compelling.

You should be aware that the "render inoperative" prohibition only applies to the commercial entities listed in S108(a)(2)(A) of the Safety Act. Owners may modify their vehicles without violating any laws or regulations administered by this agency. However, NHTSA encourages vehicle owners not to tamper with vehicle safety equipment if the modification would degrade the safety of the vehicle.

I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992.