Interpretation ID: nht79-3.25

DATE: 06/06/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Chief of Specifications; State Board of Control

TITLE: FMVSR INTERPRETATION

TEXT: This confirms your May 23, 1979, conversation with Roger Tilton of my staff in which you asked whether it is permissible for vehicles to be modified by the addition of propane gas systems replacing their regular fuel systems.

As Mr. Tilton stated, the National Highway Traffic Safety Administration permits the type of modification mentioned above. If the modification is done to a new vehicle, the person making the modification would be required to attach an alterer's label in accordance with Part 567.7, Certification, of our regulations. That label states that the vehicle, as altered, continues to comply with all safety standards. The standard that may be affected by such a modification would be Standard No. 301, Fuel System Integrity.

If used vehicles are being modified, the person modifying the vehicle would not be required to attach a label. However, that person would be responsible for noncompliance with safety standards if he or she knowingly rendered inoperative any element of design installed in or on the vehicle in compliance with a safety standard.