Retroreflectors
Retroreflectors (also reflex reflectors) produce no light of their own, but rather reflect incident light back towards its source, i.e., another driver’s headlight. They are regulated as automotive lighting devices, and specified so as to account for the separation between a vehicle’s headlamps and its driver’s eyes. Thus, vehicles are conspicuous even when their electrically-powered lighting system is deactivated or disabled. Regulations worldwide require each vehicle to be equipped with rear-facing red retroreflectors. North American regulations also require side-facing retroreflectors, amber in front and red in the rear. Sweden, South Africa and other countries have at various times required white front-facing retroreflectors.