TRS: Effects of 24-Hour Headlight Use on Traffic SafetyStatus: CompleteReport Date: 11/15/2010 Summary: Daytime running lights -- generally low-wattage headlights that turn on automatically when a vehicle's ignition is started -- are a safety feature intended to reduce multiple-vehicle crashes during daylight hours by making vehicles more conspicuous to other drivers. In some countries, such as Canada, they are required to be standard equipment on all vehicles manufactured; in the United States they are permitted but not required, and were standard equipment on about 27 percent of new vehicles manufactured in 2005 (NHTSA, 2008). Final Deliverables: TRS: Effects of 24-Hour Headlight Use on Traffic Safety (Synthesis #TRS1009) Related Materials: Related Research: