Study On Countermeasures Of Traffic Improvement For Hongbo Roundabout

The actual traffic flow in the intersection has exceeded the optimal traffic flow of roundabout, because of persestent economical development and increasing motor amount. Traffic congestion is coming out in the roundabout, high accidents rate and high delay followed. Primary channelization design and signal timing design method can not accommodate the traffic development demand any more. In the foundation of traffic feature analysis, systematic research on the signal timing design is carried on in the paper. Firstly, an investigation and analysis on present road and traffic conditions was accomplished for Hongbo roundabout, including traffic conditions, road conditions and traffic management conditions. And also, actual capacity was calculated and level of service was analyzed. It showed that queue length had a proportional relation with traffic volume and ratio of oversize vehicles, and the same relationship between delay and traffic volume and left-turning ratio of vehicles.Secondly, application conditions, optimization methods and improvement strategies were studied for roundabout. Combining with the actual traffic conditions, optimization of urban passenger traffic structure and area road network structure, engineering improvement countermeasures and traffic management and control methods were put forward for Hongbo roundabout.Thirdly, a turning-left and two-step signal control method was put forward for Hongbo roundabout. Traffic organization design was done for Hongbo roundabout, and signal control parameters were confirmed. In addition, settings of traffic safety facilities were analyzed and studied.Finally, the VISSIM simulation software was used to simulate the signal control method and corresponding settings for Hongbo roundabout according to analysis on the roundabout's center island scale, the number of the round roads, intertwined paragraph, the width of round roads and im- and export road. It showed that the method was effective to increase the capacity and level of service, and provided improving a theoretical support and reference data for Hongbo roundabout.