The Research of Urban Expressway Free-flow Velocity
BAI Xu, ZENG Sheng-nan, DU Yu-chuan, SUN Li-jun (Key Laboratory of Road and Traffic Engineering of the Ministry of Education ,Tongji University, Shanghai 200092, China; Shanghai Highway Administration, Shanghai 200063, China)
This research is based on the urban expressway evaluation system established on the concept of equivalent capacity and it investigates into a critical index-free-flow velocity. Based on the massive data collected by the urban expressway data collection system, this research defined the status that only one vehicle crossed a specific transect and occupy less than 3 percent in a given time as free flow and analyzed the velocity of the given transect or lane. Through statistics and analysis, it is found that when in the status of free flow, vehicles' velocities on the transect or lane fit into normal distribution. Then, we give a new definition to free-flow velocity based on massive data and statistics.
【CateGory Index】： U491.112