Study On Optimization Design Of Freeway Ramp System

With the rapid development of the social economy in China, vehicle ownership is also growing rapidly. The links between the cities are getting closer. Freeways have become more and more prominent. The traffic demandes of freeway are growing rapidly. As a connecting road section between urban road and freeway, between normal road and freeway, and between freeway, ramp has both toll function and management and control function. With the characteristics of low speed in design, many interference spots, many functions, it becomes a key node to impact the road actual traffic volume for the traffic safe problems in interference spots with freeway mainline. It is necessary to provide the hardware and software support of complex electromechanical equipments for the toll function of freeway. In the concrete domestic and abroad project application, there are many problems in the design for freeway ramp system. In theory there are few studies basis and scientific support about ramp system optimization.Based on cellular automatation technology, a simulation traffic flow model of freeway ramp system was established after the characteristics of traffic flow and the influencing factors at freeway ramp system had been analyzed. The influencing to traffic safe and road actual traffic volume were analyzed about the number of toll entrance, the ramp length, and the length of interfence section in different traffic demand via the simulation experiment. These optimization design values of freeway ramp were determined by setting different parameters values. The correctness of the theory and methods were proved by the experiment results at Anjiang Toll Station of Chengtang Freeway. These optimized design values were determined the number of toll entrance, the ramp length, and the length of interfence section in different traffic demand. The design contents, which combine setting pavement physics facilities, roadside electric facilities, and other ramp measures, were proposed. The theory support can be provided including traffic accidences decreasing, traffic safe guaranteeing, and road actual traffic volume enhancing at a freeway.