Compulsory use of daytime running lights DRL for all motor vehicles was introduced in Denmark on October 1, 1990. The effect on road safety has been investigated for the first five quarters after the law became effective. Introduction of DRL was expected to decrease the number of casualtoes by 340, equivalent to an annual reduction of fice percent in daytime multi-vehicle accidents. The study demonstrates an effect about half size, and the effect is concentrated to one sigle accident situation: left-turn in front of oncoming vehicle in crossroads. This decrease amounts to 37 percent and is highly statically reliable. No significant effects have been found for other accident situations. However, other interesting changes in the accident development have been demonstrated, among these a significant decrease in the number of accidents involving drunken road users.
Abstract