Interpretation ID: aiam2237
611 Bouldin Avenue
Austin
TX
78704;
Dear Mr. McNiel: On February 12, 1976, this agency denied your petition to amend S4.5. of Motor Vehicle Safety Standard No. 108 to read:; >>>'The stoplamps on each vehicle shall be activated upon applicatio of the service brakes, or by other beneficial means which will not impair the lighting system or the mechanical functioning of the vehicle.'<<<; You have now re- petitioned us on February 16, 1976, to amend S4.5.4 t read:; >>>'The stoplamps on each vehicle shall be activated upon applicatio of the service brakes. This action may be supplemented by other beneficial means which will improve the performance of the stoplamps without impairing the lighting system or the mechanical functioning of the vehicle.'<<<; This petition is unnecessary, because as you have now worded you suggested amendment it essentially reflects the present requirements of the standard. We do not view S4.5.4 as prohibiting a means of stoplamp activation supplemental to activation by application of the service brakes.; Any supplemental lighting device, however, is subject to the genera prohibition of S4.1.3 against installation of motor vehicle equipment that impairs the effectiveness of lighting equipment required by Standard No. 108. For example, a positioning device that activates the stoplamps whenever the accelerator pedal is released would impair the effectiveness of the stoplamps by providing an ambiguous signal, as release of the accelerator does not always signify that the vehicle operator intends to brake.; You also questioned whether NHTSA desires to see improvements in moto vehicle stoplamp systems. Docket No. 74-5 represented a tenative (sic) effort to provide better systems on an optional basis, but on the basis of comments to the docket and our research contracts, we are re-evaluating the entire subject. Your denial must also be considered in this context, and at the present time radical changes in rear lighting are simply premature.; The remainder of your letter was also of interest. Dr. Haddon remarke that performance standards afford the private sector optimum flexibility in designing to meet the Federal standards. His comment reflected a statutory mandate which this agency continues to adhere to in its rulemaking actions. However, as I wrote you on February 12, any performance standard is design restrictive to some extent, with the restrictions ideally only as narrow as reasonably necessary to achieve the desired safety performance. In some areas (*e.g.* the occupant protection provisions for vehicle interiors in impacts, Standard No. 201) a great deal of design freedom is afforded, while others (*e.g.* the headlighting requirements of Standard No. 108) may be quite restrictive because safety-related factors such as availability of replacements, uniformity of color and location, and detection of function are more important than design freedom.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs;