Research On Traffic Organization Method For Displaced Left-Turn Intersection

Traffic congestion has become one of the key issues restricting the sustainable development of China's cities.The intersection is the key node of the urban road network.Reasonable intersection organization design and signal method control play an important role in improving traffic efficiency.In recent years,the emergence and application of unconventional intersections have received more and more attention.In this paper,the characteristics of traffic organization and operation are analyzed for displaced left-turn intersection,and the signal control method for displaced left-turn intersection is proposed.Firstly,the left-turn traffic flow organization methods commonly used in urban signalized intersections are analyzed,their advantages,disadvantages and applicable conditions in terms of cost,duration and efficiency are compared.The problem of the current displaced left turn is optimized and improved.From the perspective of traffic flow efficiency and safety,the differences between the two organizational methods before and after improvement are compared and analyzed.Based on the operational characteristics of traffic flow in China,the calculation methods of design points for displaced left-turn intersections are summarized,including displaced left-turn lane length,lane-changing length of left-turn vehicle,and the length of storage section of left-turn vehicle.To lay the theoretical foundation for the practical application of displaced left turn in China.Secondly,the traffic signal control method of displaced the left turn intersection is analyzed,and the coordination relationship between the main pre-signals is expounded.Based on the improved displaced left-turn organization mode,the delay variation of traffic flow in different phases and different directions is analyzed,and the calculation model of vehicle delay in the displaced left-turn intersection is established.Aiming at the minimum delay of intersections,the signal control optimization model was established,and the applicable conditions of the optimization model were analyzed and verified,including the influence of the Displaced Left-turn lane length on the traffic efficiency of left-turns,the influence of Displaced Left-turn lane length on the intersection delay,the influence of left-turn traffic volume and the number of Displaced Left-turn lanes on the intersection delay,the influence of the right-turn proportion in the cross direction on intersection delay.Finally,the actual intersection in Harbin is taken as a case.Through the VISSIM simulation,the current intersection and the optimized design scheme are compared and analyzed.In order to ensure that the intersection model established in VISSIM is as close as possible to the actual intersection environment,and the accuracy and accuracy of the output results are ensured,the VISSIM simulation parameters are calibrated.After running the simulation,it was found that the average vehicle delay of the optimized design was significantly lower than the current intersection,and the delay was reduced by 31.5%.It is verified that the method proposed in this paper is feasible and effective.