Design of the Left-turn Variable Lane at Signalized Intersection

In view of the congested situation of left-turn lane caused by directional uneven traffic distribution at some urban signalized intersections,this paper proposes a traffic organization method by designing left-turn variable lane to reduce road resources waste.Based on the research theories of variable lane,this paper induces the static and dynamic application condition and derives the calculation model of parameters such as lane length,opening and closing time.Using a signalized intersection in Weihai as an example,based on actual traffic investigation,this paper proposes the feasibility of the left-turn variable lane and analyzes the model by Vissim micro-simulation.Simulation results show that the left-turn efficiency after setting the left-turning variable lane can be greatly improved with left-turn delay reduced by 51% and queue length reduced by 72%in 20 cycles.