Investigation of Operation Speed and Suggestion ofûSpeed Limit of Freeways in China

Speed limit is an efficient measure to improve the safety of freeway. However, there are few studies on speed limit in China. 107 typical sections of fifteen freeways in China were investigated according to different terrain condition, traffic volume and geometric alignment. By analyzing observed data of 107 sections, speed distribution and the changing rule of speed in China are obtained. The power relation model between operation speed and radius and the linear relation model between operation speed and gradient are established respectively by means of regression analysis. According to the two models, it is suggested that speed limit should be set by different radius and gradient. Rational suggesting values of speed limit for freeways in China are put forward from the viewpoint of the safety. For the covering abstract see ITRD E135448.