According to a report, the U.S. National Highway Traffic Safety Administration is still struggling with the issue of whether or not to make daytime running lights mandatory, calling for more research on the matter. NHTSA says it will drop a proposal to reduce the allowable brightness of daytime running lights and instead consider whether to require the feature on all new vehicles. General Motors Corp., which has been installing the systems in its U.S. vehicles since 1995, petitioned NHTSA in 2001 to make them mandatory. The agency acknowledges its own research supports GM’s claims that the lights help reduce accidents, but it says it wants to conduct more research before issuing new standards for the lights, which are touted as especially helpful at making vehicles more visible to pedestrians and other drivers at dusk and in gloomy weather. It was not known whether that research would include asking Canadian authorities about their decades old experience.