The headlight sensors are often used as complements to road markings, and allow to retro-reflector the light they receive from the vehicles that circulate. In this way, these safety pieces serve as an alert to drivers about the limits or dangers of the road, thus avoiding accidents, or preventing many of them.

Headlamps can perform different specific functions:

• If placed on the pavement, they serve as a horizontal guide to reflect incident light and help drivers spot the margins of the road, in low-light environments.
• By placing them on safety barriers, walls and parapets, they serve as a vertical guide for the delineation of the road margin.
• Headlamps for concrete barriers are a solution for safety in linear reflectorization against concrete barriers. 
• The retro-reflectors for edge milestone are signaling elements that allow to distinguish the limits of the road in low light conditions. They offer good retroreflection from different angles of light incidence and night visibility, both on straights and curves.