Abstract
Contraflow Left-Turn Lanes (CLLs) have the potential of being a solution for mitigating congestions at signalized intersections where split phasing is recommended or required. However, the current signal timing strategy for the intersections with CLLs cannot be directly applied at the signalized intersections with split phasing (SIWSP). To address this problem, this study proposed an innovative signal timing strategy, which is referred to as Counterclockwise Split Phasing (CSP) signal timing, for implementing the CLLs at the SIWSPs. A traffic simulation-based case study was conducted and the results indicate that, by using the proposed CSP signal timing plan, CLLs can be implemented at the SIWSP and can significantly reduce the traffic congestions caused by the high left-turn demand at this type of intersection. In addition, since the proposed CSP signal timing design procedure has fully considered the clearance time requirements for the left-turn vehicles on the CLLs, the risk associated with the use of CLLs can be controlled which makes it safe to use this innovative intersection design at SIWSPs.
Highlights
Traffic congestion is a critical issue for the sustainability of transportation development.It can cause traffic delays, reduced economic efficiency, and safety and air pollution problems.As traffic congestion increases, the need to maximize the utilization of existing lane configurations, and improving the sustainability of the transportation system, is of great importance
The results show that the proposed Contraflow Left-Turn Lanes (CLLs) intersection increases the capacity of an intersection and reduces average intersection vehicle delay and queue length compared with the conventional intersection design
The results indicate that the CLL design can improve the intersection capacity and reduce traffic delay compared with the conventional left-turn lane design
Summary
Traffic congestion is a critical issue for the sustainability of transportation development.It can cause traffic delays, reduced economic efficiency, and safety and air pollution problems.As traffic congestion increases, the need to maximize the utilization of existing lane configurations, and improving the sustainability of the transportation system, is of great importance. Traffic congestion is a critical issue for the sustainability of transportation development It can cause traffic delays, reduced economic efficiency, and safety and air pollution problems. Lane (CLL), is designed for solving the problem where the capacity of the existing regular left-turn lanes is insufficient for the increasing left-turn demand at a signalized intersection. The CLL is designed for use at signalized intersections with lead-lead protected left-turn phases. The entered left-turn vehicles will wait at the CLL until the left-turn signal at the main intersection turns green. They move together with other left-turn vehicles on the adjacent regular left-turn lane(s) during the leading left-turn phase. Note that the pre-signals will turn red before the left-turn signal at the main intersection turns red, and enough clearance time (CT) will be provided to ensure that all the left-turn vehicles on the CLLs can be cleared before
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