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DriversDriver Education & Road Safety
Daytime Running Lights (DRL's)
Daytime running lights (DRLs) are a crash avoidance feature. They've been used for years in Canada and Scandinavia.
DRLs help prevent crashes by making vehicles more conspicuous. Our law permits but does not require DRLs, which turn on automatically when the ignition is started and are overridden when regular headlights are activated. DRLs typically are low-beam headlamps at full or reduced power.
What are the safety advantages of DRLs?
Daytime running lights are a low-cost method to reduce crashes. They are especially effective in preventing daytime head-on and front-corner collisions by increasing vehicle conspicuity and making it easier to detect approaching vehicles from farther away.
Where are DRLs required?
Laws in Canada, Denmark, Finland, Hungary, Iceland, Norway, and Sweden require vehicles to operate with lights on during the daytime. There are two types of laws. Canada's requires vehicles to be equipped with DRLs. The other type of law -- in effect in Denmark, Finland, Hungary, Iceland, Norway, and Sweden -- requires motorists to turn on their headlights if their vehicles do not have automatic DRLs. This kind of law applies to drivers only, and vehicles do not have to be specially equipped. In 1972, Finland mandated daytime running lights in winter on rural roads and a decade later made DRLs mandatory year-round. Sweden's law took effect in 1977, Norway's in 1986, Iceland's in 1988, and Denmark's in 1990. Hungary has required drivers on rural roads to operate with vehicle lights on since 1993. Canada requires DRLs for vehicles made after December 1, 1989.
How effective are DRLs?
Nearly all published reports indicate DRLs reduce multiple-vehicle daytime crashes. Evidence about DRL effects on crashes comes from studies conducted in Scandinavia, Canada, and the United States. A study examining the effect of Norway's DRL law from 1980 to 1990, found a 10 percent decline in daytime multiple-vehicle crashes. A Danish study reported a 7 percent reduction in DRL-relevant crashes in the first 15 months after DRL use was required and a 37 percent decline in left-turn crashes. In a second study covering two years and 9 months of Denmark's law, there was a 6 percent reduction in daytime multiple-vehicle crashes and a 34 percent reduction in left-turn crashes. A 1994 Transport Canada study comparing 1990 model year vehicles with DRLs to 1989 vehicles without them, found that DRLs reduced relevant daytime multiple-vehicle crashes by 11 percent.
In the United States, 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. A small-scale fleet study conducted in the 1960s found an 18 percent lower daytime multiple-vehicle crash rate for DRL-equipped vehicles. Multiple-vehicle daytime crashes account for about half of all police-reported crashes in the United States. A 2000 Institute study reported a 3 percent decline in daytime multiple-vehicle crash risk in 9 U.S. states concurrent with the introduction of DRLs. Federal researchers, using data from 4 states, concluded that there was a 7 percent decline.
Will DRLs shorten headlamp bulb life or lower fuel economy?
Running vehicle lights in the daytime does not significantly shorten bulb life.
Will motorists be bothered by glare?
In most countries mandating DRLs, glare has not been an issue.