A daytime running lamp (DRL) is a lamp on a motor vehicle that remains illuminated whenever the vehicle is on, day or night, providing more visibility during daylight hours when the lights are usually left off. The lights typically activate when people release their parking brakes in preparation for driving. Such lights are standard on a number of vehicles and are required by law in some regions. Drivers unsure about the legal status of daytime running lights can consult a police officer or regional vehicle code for more information.
Depending on design, the lamps may be built into the headlights or installed in the headlight array. They are only present in the front of the vehicle, unlike running lights associated with headlights on a low setting, which illuminate along the sides of the car and in the rear. Studies by a number of safety organizations show a significant safety benefit with daytime running lamp usage, particularly in areas with dark days, like Russia and Scandinavia.
In response to safety studies, some areas have required the installation of such devices on new vehicles with the goal of reducing traffic accidents. In other areas, they are legally permitted, but not required, and motorists can choose whether to use them. The power usage with a daytime running lamp is typically very low to reduce strain on the vehicle's electrical system, and the lights are unobtrusive to limit problems with glare. When mounted as part of a headlight, they can also be adjusted if there are concerns about light pollution or other problems.
New cars often come standard with this lighting. It is possible to disconnect the circuit if a driver feels strongly about a daytime running lamp. Conversely, conversation kits can be purchased to increase visibility by installing extra lights on the vehicle to make the car easier to spot during the day. This is especially recommended for pale cars in foggy and dim conditions, as they tend to melt away visually and can be hard for other drivers to see.
Some groups have raised concerns about daytime running lamps, including motorcyclists worried about visibility, since historically motorcycles were the only vehicles on the road with daytime running lamps. Others have noted that people may rely on daytime running lamp lighting in marginal conditions when they would normally have the headlights on a low setting, meaning that no lights are illuminated in the rear of the vehicle and potentially creating a risk of rear end collisions in poor visibility.
