This SAE Standard defines and provides a means for the control of colors employed in motor vehicle external lighting equipment, including lamps and reflex reflectors. The document applies to the overall effective color of light emitted by the device in any given direction and not to the color of the light from a small area of the lens. It does not apply to pilot, indicator, or tell-tale lights.
The 2002 revision of the standard saw a change in representation from 2 to 3 significant figures of the color boundaries. In this revision the following boundaries were harmonized with the ECE requirements through a change in the 3rd significant figure. White boundary on selective yellow, red boundary on selective yellow, red boundary on white. When rounded to two significant figures these boundaries are unchanged from the historical SAE J578 boundary values.
In the 2002 version the blue boundary on white was changed from x = 0.31 to x = 0.300 to accommodate requirements in emergency warning devices standards. In this revision the blue boundary on white was restored to the historical value x=0.310, in harmonization with ECE color requirements. A typographical correction was made to the violet boundary on signal blue.