Mixed Traffic Flow Characteristic of the Ramp of Urban Overpass

To study the microscopic characteristics of motor and non-motor vehicles in urban overpass, two ramps which located at Xizhimen and Jimenqiao of Beijing were investigated by video and manual survey. The data include speed, arrival characteristic, lane width, slope and so on. The arrival characteristic of straight bicycle obeys a negative binomial distribution. Without causing traffic jams, the average speed of straight bicycle is reduced by 0.17m/s by traffic conflict and the average speed of right vehicle is reduced by 1.4m /s. By the measured data, the regression models of vehicle speed - acceleration and the safety speed of turning were established. Finally, the ramp was simulated by the simulation software VISSIM. The simulation-related parameters were calibrated by the measured data. The impact of right-turn vehicle delays was analyzed, and then the traffic congestion threshold was proposed.