The Application of Parallel Flow Intersection: Discussion on Asymmetric Flow Input and Area Restriction

As a variant of displaced left-turn intersections, parallel flow intersection (PFI) resolves the conflict between left-turn traffic and its opposing through traffic by rerouting the left turn using a bypass. This paper adopts a lane-based optimization model for PFI design, which determines the lane configuration and signal timing simultaneously. The optimization is formulated as a mixed integer linear program (MILP). The effectiveness of the optimization model is verified by extensive simulation and numerical analysis. Given the space limitation of lane layout, effects of turning ratio, traffic volume, and symmetry are practically considered for the experiments design. Detailed analysis results of average delay, queuing length, and capacity of intersections in different traffic scenarios indicate that PFI has preferable performance on high traffic volume occasions. In general, reducing delay or queuing length and increasing capacity are usually mutually promoting.