Interpretation ID: nht73-3.2

DATE: 12/03/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Mercedes-Benz of North America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of September 24, 1973, concerning the conformity of an emergency feature of Mercedes-Benz's interlock system to S7.4.3 of Standard No. 208.

The feature you describe would permit the engine starting system to be operated without belt use for a period of 3 minutes after an activation knob inside the engine compartment is depressed. If the vehicle stalls, the driver would have to leave his seat, open the hood, depress the knob, close the hood, and return to his seat, at which point the interlock would be deactivated for the 3-minute period. This bypass feature would apparently supplement other convenience aspects provided pursuant to S7.4.3.

After review of the Mercedes system we have determined that it would not result in bypassing the interlock in situations where that would not be permissible under S7.4.3 or S7.4.4. We therefore conclude that it is an allowable system and that it may be installed.

Yours truly,

MERCEDES-BENZ OF NORTH AMERICA, INC.

September 24, 1973

National Highway Traffic Safety Administration Dr. James B. Gregory, Administrator

Subject: Request for Interpretation of S7.4.3 of Federal Motor Vehicle Safety Standard 208

As previously reported to motor vehicle program engineers, Daimler-Benz AG., the parent company of Mercedes-Benz of North America, Inc., intends to install an engine-starting system operable without interference from the belt interlock system after the engine has stopped as provided in S7.4.3 of Standard 208. We are of the opinion that the by-pass device is in conformity with Standard 208, but we seek this interpretation of the referenced section for clarity. However, if the administration interprets S7.4.3 so as to not allow the below-described Mercedes by-pass system, then we request that this letter be considered as a petition for rulemaking to amend FMVSS 208 to allow incorporation of such a system in order to deal with the problem of a simultaneous engine stallout at a busy intersection and failure in the interlock system logic sequence. Obviously, such an occurrence could create a hazardous situation for the operator and occupants of a vehicle.

The Mercedes-Benz by-pass device will be tied in with the three minutes free starting period and would operate as follows:

In case of simultaneous engine stall and failure in the logic of the interlock system, the driver will have to open the front hood from inside the vehicle, leave the vehicle, and activate the system by depressing an activation knob located in the

2 engine compartment. The hood is then closed and the driver returns to his position within the vehicle at which point the interlock logic system becomes inoperative for a maximum of three minutes thus permitting repeated starting of the engine even though the driver and front seat passenger are not belted.

We feel this system addresses an important problem which can be encountered in normal driving especially in urban centers and would be in conformity with the present requirements of the standard. Needless to say, there is some urgency to this request for interpretation considering the rapidly approaching introduction date for 1974 model Mercedes equipped with the interlock belt system. Your favorable attention to this request would be most deeply appreciated.

Very truly yours,

H. W. Gerth Assistant Vice President