Investigating the role of urban road light in increasing of safety

Road light is one of important factors in road safety. In most country, light system is an element of transportation system. Adequate light in dim condition specialty at night cause safety increasing. Road light is more important in urban roads. Urban road light increase safety in street and provide safety environment for pedestrian, on the other hand, road light increase citizen social security in criminal events. Main goal of road light is presentation of proper vision for road users (drivers of truck, car: bus) motorcycle and pedestrian and other citizens. Favorite light decrease traffic accident risk and accident severity. In this research, required factors mentioned for necessary of road light, and then implied light effects on safety.