Mr. Glenn Panes, 6/14/99

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This document retrieved from the NHTSA legal interpretations database.

Mr. Glenn Panes
921 Todville Road
Seabrook, TX 77586

Dear Mr. Panes:

This is in reply to your e-mail of April 7, 1999.

You are interested in buying an aftermarket combination stop/turn signal lamp which has a clear lens and red and amber bulbs. You ask whether the lamps are legal to use. Apparently your local police do not object, but you are concerned about being stopped somewhere else.

The answer to your question depends on a number of factual issues, as well as the laws of local and state jurisdictions. Therefore, this is not a question we can fully answer for you.

We establish the Federal motor vehicle safety standards that apply to new motor vehicles and vehicle equipment from the time of manufacture until time of first sale. One of these, Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment specifies the lighting equipment a vehicle must have when manufactured, and the performance of this original equipment and the aftermarket equipment intended to replace it. We can tell you how this standard relates to the aftermarket lamp you describe.

Aftermarket replacement equipment is required to comply with Federal new-equipment requirements, and be certified as complying. We are unable to tell whether the combination stop/turn signal lamp you describe complies but would like to make a few comments on it. Under Standard No. 108, a turn signal lamp is permitted to emit amber light. The amber light may be provided by either an amber lens and clear bulb, or an amber bulb and a clear lens. The question, then, is whether the turn signal lamp meets Standard No. 108's photometric specifications.

Standard No. 108 has incorporated by reference the Society of Automotive Engineers (SAE) specifications for amber turn signal lamps.

SAE specifications for stop lamps are also incorporated by reference in Standard No. 108. These specifications require the use of special bulbs for testing purposes. However, SAE has no specifications for red bulbs. Thus, it may not be possible for manufacturers to certify that a lamp meets all applicable Federal motor vehicle safety standards. Nevertheless, if the manufacturer has marked the replacement lamp with a "DOT" symbol (or certified its conformance on its container), you may regard that as its representation that the lamp meets all applicable Federal requirements.

This certification, however, does not mean that the original equipment lamp can be removed and the new, different one substituted without causing a noncompliance with Standard No. 108. The standard requires vehicles to have two red reflex reflectors on their rear, and one on each side at the rear. In many instances, these reflectors are incorporated into red rear combination lamp lenses. Thus, depending on the location of red reflex reflectors on the side and rear of the car, substitution of a white-lensed stop lamp might remove this desirable safety feature.

Even if the lamp were certified as complying, if installation of the lamp you are interested in would result in removal of the only reflex reflectors on the side and/or rear, there would be a violation of Federal law if this work was performed by a manufacturer, distributor, dealer, or motor vehicle repair business, and if the modifier did not add two reflex reflectors to the rear of the car. However, this prohibition does not apply to you, if you, the vehicle's owner, substitutes the lamp. Nevertheless, it is possible that you could be cited somewhere for a violation of local laws if the vehicle lacks rear reflex reflectors. As a general rule, we urge caution in replacing any lighting equipment with novelty items.

Some new motor vehicles may be equipped with original equipment rear combination lamps that have clear lenses, but the red color of the light emanating from these lamps is produced by a clear bulb projecting through a red inner plastic lens. Such lamps do not use red bulbs and are certified as complying.

If you have any further questions, you can contact Taylor Vinson of this Office, either by phone (202-366-5263), or by e-mail (

Frank Seales, Jr.
Chief Counsel


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This site is not affiliated with any Federal, State, or Local organization.  The goal is to be as factual as possible, however, the views expressed on this site are the opinions of the author and should not be used to determine the legality of motor vehicle equipment in accordance with Federal laws.  If you require a legal interpretation of your specific situation concerning FMVSS No. 108, you should contact the National Highway Traffic Safety Administration's Office of Chief Counsel.