As part of National Cooperative Highway Research Program (NCHRP) Project 5-19, a number of studies on the effects of roadway lighting on safety, crime, perceptions of security, economic development and light pollution are summarized. There is a good amount of variability among published findings, and most likely there are biases that tend to inflate the benefits of roadway lighting in terms of nighttime crash reduction and crime reduction. Nonetheless, the literature reviewed in the present report suggests that roadway lighting can contribute to reductions in nighttime crashes and to reductions in crime.