Interpretation ID: 21478.ztv

The Honorable Richard S. Lugar
United States Senate
Washington, DC 20510-1401

Dear Senator Lugar:

I am responding to your recent letter to Rosalyn Millman, Acting Administrator of the National Highway Traffic Safety Administration, on behalf of your constituent, Mark Steele of Goshen. You have enclosed a copy of Mr. Steele's letter to you of February 29, 2000, and asked that we address his additional concerns. Mr. Steele appears to have sent you copies of our correspondence with him dated December 6, 1999, and February 25, 2000, as well as copies of interpretive letters sent to Safety Alert Company in 1983 and Mazda Motors Corporation in 1990.

Mr. Steele believes that it would be in the interest of motor vehicle safety to introduce his proprietary device that would automatically activate a vehicle's hazard warning system lamps when a vehicle is rapidly braking. We have corresponded with Mr. Steele on this subject, not only on December 6, 1999, and February 25, 2000, but initially on October 7, 1999. I enclose a copy of this letter because it is necessary for an understanding of our position vis-a-vis his invention, and why it is not permitted under the relevant regulation, Federal Motor Vehicle Safety Standard No. 108.

Mr. Steele's device would activate the hazard warning system lamps when "a vehicle [is] trying to brake at a rate of deceleration above the vehicle's current capability and the vehicle has automatically initiated its ABS to help maintain some control." Standard No. 108 requires a vehicle's stop lamp system to be activated when the brakes are applied so that, in the situation posited by Mr. Steele, a following driver will already have received a signal that the vehicle ahead is braking before the hazard warning system begins to flash. We therefore do not understand how safety would be improved by this device. We note, too, that Mr. Steele has submitted no data derived from tests of his device demonstrating that it would reduce either the frequency or severity of rear end crashes. His belief that it would enhance safety is speculative.

It is our conviction and that of motor vehicle safety authorities in other countries that motor vehicle safety is best served by standardization of lighting performance, including that on the rear of vehicles. Over the years we have come to believe that lamps must perform only their assigned function, and our interpretations of Standard No. 108 have become more conservative. We did advise Safety Alert Company in 1983 and Mazda in 1990 that the hazard warning system could be used for purposes other than originally intended. We are no longer of that opinion, and our letter of October 7, 1999, to Mr. Steele should be viewed as reversing those interpretations. We believe that S5.1.3 of Standard No. 108 prohibits new uses for required lighting equipment like hazard warning lamps. That section prohibits additional equipment that "impairs the effectiveness" of required lighting equipment. Since Mr. Steele's idea confuses following drivers about the hazard warning lamps, it is expressly prohibited by our standard.

Our position remains as explained in our October 7 letter. When stop lamps are activated, a following driver must react instinctively to the signal. Hazard warning signals are provided through a vehicle's turn signal system. If the stop lamps suddenly begin to flash (as would be the case where the rear turn signals are red and optically combined with the stop lamp) or are supplemented by flashing hazard lights (as would occur when the turn signal lamps are amber) there is the potential of confusing, at least momentarily, the driver following. To be sure, a driver can activate the hazard warning system at any time, but, in general, does so to indicate either that (s)he is proceeding at a slower rate than surrounding traffic, or that the vehicle is stopped on or off a roadway. Activation of the hazard warning lamps should depend on the driver's evaluation of the driving environment and not occur involuntarily simply because the vehicle is decelerating.

I hope that this responds to your concerns. Should you have any further questions, please contact Charlotte Hrncir, NHTSA's Director of Intergovernmental and Congressional Affairs, at (202) 366-2111.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosure
ref:108
d.5/9/00