Interpretation ID: aiam3429
President
CSMPCO Corporation
P.O. Box 18836
San Jose
CA 95158;
Dear Mr. Chicoine: Thank you for your letter of March 3, 1981, providing additiona information about the 'Downshift Warning System Kit.'; After reviewing this information and the points you make concernin Federal Motor Vehicle Safety Standard No. 108, we wish to point out that the pertinent provisions of this standard are S4.1.3 and S4.5.4. For your information, a copy of Standard 108 is enclosed.; You will note that S4.1.3 provides that: 'No additional lamp reflective device or other motor vehicle equipment shall be installed that impairs the effectiveness of lighting equipment required by the standard.' Further, you will note that S4.5.4 provides that: 'The stop lamps on each vehicle shall be activated upon application of the service brakes.' This means that your system must not impair the effectiveness of the stop lamps that are original equipment on the vehicle, and that any application of the service brakes that does not activate the stop lamps would be inconsistent with Federal requirements. As we have made no formal study of your system, you will have to determine whether a vehicle on which it is installed would meet Standard No. 108.; Also enclosed for your information is a copy of the National Traffi and Motor Vehicle Safety Act. Section 108(a)(2)(A) is interpreted to mean that the installation of your system on a used vehicle by a person other than its owner must not render inoperative in whole or in part, the stop lamp system. However, the prohibitions of the Act and the standard do not cover sale of your system as an aftermarket device nor its installation solely by the vehicle owner. Use of it is subject to State regulation.; We would also like to call your attention to the agency's study: 'Fiel Test Evaluation of Rear Lighting Deceleration Signals - Analytical and Experimental Studies (1979)' (DOT HS 805 061). We urge that you obtain a copy of this report and consider it carefully with regard to your system. You may obtain a copy by writing to the National Technical Information Service, Springfield, Virginia 22161.; The agency has tentatively decided that a single high-mounted auxiliar stop lamp is the most effective way of preventing rear end collisions and has proposed that such be made available both as original equipment and in the aftermarket. I enclose a copy of the proposal for your consideration.; Sincerely, Frank Berndt, Chief Counsel