Relation between speed and maximum speed limit with safety in Road network

Safety is one of necessary infrastructures for constant development. Road safety is very important and have a considerable role in reducing of wastage and injury and fatal accidents effective factors in accidents are road problems technical fault and human factor. According to statistics and expert ideas, 20 percents of accidents happen because of road problem, 10 percents happen because of technical fault and 10 percents occur because of human factor. In recent years, with technology deployment in vehicle design and increasing of standard roads, human factor role being main important factor in accidents occurring unauthorized speed is a main important factor in appearing human errors. This article have been considered to execution resolutions in other countries and speed management for road safety increasing. Speed controlling have a basic role in safty improvement. Investigation show that reducing the maximum speed limit have diminished accident severity and risk of accidents.