Interpretation ID: nht72-3.40
DATE: 08/04/72
FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA
TO: General Motors Technical Center
TITLE: FMVSS INTERPRETATION
TEXT: Your letter of July 11, 1972, raises two substantive questions concerning the belt system requirements of Motor Vehicle Safety Standard No. 208.
The first question concerns S7.4.1, which provides that the engine starting system shall not be operable "unless the belt system at each occupied front position is operated after the occupant is seated". You ask whether a system that you submitted for our inspection, which does not use electronic logic circuits, would conform to this requirement.
The belt system in question is designed to make it quite difficult to enter the vehicle if the belt system is fastened. The occupant is thus forced to unfasten the belt (if it has been left fastened) to enter the vehicle, then to fasten it in order to start the engine. The system employs an inboard-mounted shoulder belt with the outboard attachment point for the lap and shoulder belts mounted in the door. The ignition system employs a buckle switch, so that the belt must be buckled for the engine to start. Upon entering the vehicle, an occupant may find that the belt is either buckled or unbuckled, depending on the action of the previous occupant, but if it is buckled, he will find entry difficult if he does not first unbuckle it. After evaluating the system, we have concluded that the occupant is essentially compelled to operate the belt system after being seated in order to start the car. The system therefore conforms to the requirements of S7.4.1.
In view of the lack of logic circuits, we urge that the design of the buckle be given careful attention, to prevent defeat of the system by the insertion of objects into the buckle.
Your second question concerns the acceptability of belts which require "some action during normal vehicle entry or egress" under the requirements for passive belts. As presently drafted, S4.5.3 does not permit such belts to be classified as passive belts. We will treat your request for amendment of this requirement as a petition for rulemaking and give it prompt consideration.