What are daytime running light (DRL's), and what safety benefits do they provide?
Daytime running lights (DRLs) are headlights that are lit whenever a vehicle is running. A low-cost method to reduce crashes, they are especially effective in preventing daytime head-on and front-corner collisions by making it easier to see vehicles, particularly as they approach from far away
Where are DRLs required?
Laws in Canada and many European countries require vehicles to operate with lights on during the daytime. Canada requires vehicles made after Dec. 1, 1989, to be equipped with DRLs. The European Union requires DRLs for new cars and small vans under a law that took effect in February 2011. New trucks and buses in the EU must have DRLs starting in August 2012.
No U.S. state mandates DRLs, but some require drivers to operate vehicles with lights on in bad weather.
Are DRLs available on vehicles in the United States?
First offered on a handful of 1995 domestic and foreign model passenger cars, pickups and SUVs, daytime running lights have become a more common feature. They are standard on all General Motors, Honda, Subaru, Volkswagen and Volvo models. Other manufacturers also offer daytime running lights on certain models. GM offers retrofit kits for vehicles that do not already have DRLs. The kits can be used on non-GM models, too.
How effective are DRLs?
Nearly all published reports indicate DRLs reduce multiple-vehicle daytime crashes. A 1985 Institute study determined that commercial fleet passenger vehicles modified to operate with DRLs were involved in 7 percent fewer daytime multiple-vehicle crashes than similar vehicles without DRLs. Multiple-vehicle daytime crashes account for about half of all police-reported crashes in the United States. A 2002 Institute study reported a 3 percent decline in daytime multiple-vehicle crash risk in nine U.S. states concurrent with the introduction of DRLs.
Federal researchers, using data collected nationwide from 1995 to 2001, concluded that there was a 5 percent decline in daytime, two-vehicle, opposite-direction crashes. 3 However, a 2008 federal study concluded that DRLs reduce crash involvements of pickups, SUVs, and vans, but have no significant effect on crashes of passenger cars.
Will DRLs shorten headlamp bulb life or lower fuel economy?
Running vehicle lights in the daytime does not significantly shorten bulb life. Systems like those on GM cars that use high beams are designed to operate at half their normal power during daylight hours, thereby conserving energy and reducing the effect on a vehicle's fuel economy. The National Highway Traffic Safety Administration (NHTSA) estimates that only a fraction of a mile per gallon will be lost, depending on the type of system used.
Are motorcycles required to have DRLs?
Federal law does not require motorcycles to have DRLs, but some states require motorcyclists to ride with their headlights on at all hours. Since 1979 most manufacturers have equipped their cycles with automatic-on headlamps.
Information provided by: Insurance Institute for Highway Safety (IIHS)