Traffic Performance in Signalized Intersection with Shared Lane and Left-Turn Waiting Area Established

Abstract

This paper highlights the left-turn waiting area in an intersection and proposes a different perspective for measuring the capacity of the traffic flows, which permits the through vehicles to queue on the left lane in a protected signal operation. The effect of flow diverting from the through lanes on the left lane is quantitatively analyzed with random service system theory and probability theory. The utilization of the left-turn waiting area significantly improves the discharge rate of the through lane without compromising the efficiency of left-turning flows, thus reducing the average vehicle delay. A typical intersection with a different capacity of left-turn waiting area is presented to verify the advantage of shared-use operation in the average delay. Besides, effects of the length of the left-turn waiting area, green ratio, and left-turn proportion on the capacity in shared lane are constructed in different conditions. The relationships between these parameters and the actual capacity are presented to show the trade-off between shared use and the exclusive configuration. Theoretical analysis and simulation results show that the shared-use style still works even when the arrival rate of through flows reaches the road capacity, which may result in congestions.