Daytime Running Lights

Daytime running lights (DRLs) are an additional safety feature designed on vehicles to improve the vehicle’s visibility to other drivers in all weather conditions. They are existing lights that turn on when the vehicle is running and turn off when the engine stops. The lamps on the front are the headlights, which are typically operated at about a 60% power level, providing light without excessively decreasing bulb life or using full electrical power. The lamps used on the rear in DRL systems are the taillights.

DRLs are mandatory on modern vehicles licensed in Canada and some other countries. In the United States, DRLs are permitted but not required. Their use is somewhat controversial. First, if they are too bright, they can cause daytime glare. Second, they tend to mask the visibility of turn signals, making it harder for other drivers to determine a vehicle’s intent. Overall, they have not been proved to reduce accidents or increase safety. They also require energy to operate, which reduces fuel economy and increases carbon dioxide emissions.