Abstract
Daytime running lights (DRL) have been proposed as a means of reducing traffic accident frequency and severity by enhancing the conspicuity of vehicles to other drivers and DRL regulations have been enacted in several countries. Although various studies of DRL effectiveness have been conducted, only one study has included the entire range of ambient illumination conditions experienced in U.S. driving experience. A peripheral detection study was recommended as the primary approach for evaluation of DRL. This study is presented in the report here.