Tram-Oriented Traffic Signal Timing Resynchronization

Yuxiong Ji,Wei Wang,Yuchuan Du,Yu Tang

doi:10.1155/2018/8796250

Abstract

Modernized trams usually run on exclusive rail lanes along urban streets, but they share the right of way with general vehicles at intersections and often get interrupted by traffic signals. We developed a mixed integer model to resynchronize traffic signal timings to favor tram movements. The objective is to balance the operational needs between minimizing bidirectional tram travel times and reducing the likelihood of activating the green extensions. The model depicts both tram and vehicle progressions in one signal timing plan, making it possible to control the impact of signal timing resynchronization through traffic. Trams following the tram bands produced by the proposed model are prevented from being stopped by red phases at signalized intersections. The applicability and effectiveness of the proposed model were demonstrated in a real-world case study. Compared with the state-of-the-art practice approach, the developed model reduced tram travel time by 10% with lower negative impacts on traffic on side streets. The reduction in tram travel time was obtained without sacrificing the mobility of through traffic.

Highlights

Modernized tram systems have been adopted as an environment-friendly transit mode in many cities
Assuming that signal timing plans that have been optimized for general vehicles are given, we propose a methodology to resynchronize traffic signal timings in a subsystem to favor tram movements
We developed a mixed integer model to resynchronize traffic signal timings to favor tram movements

Summary

Introduction

Modernized tram systems have been adopted as an environment-friendly transit mode in many cities. Compared with buses, modernized trams possess larger capacity, improved level of comfort, and a higher degree of right of way. Modernized trams, especially in Asian counties, run on exclusive rail lanes along urban streets, but they share the right of way with general vehicles at intersections [1]. Many methodologies have been proposed to optimize traffic signal timing to improve vehicle mobility and safety. Webster [2] developed a method to optimize green time allocation at an isolated intersection. Robertson [3] and Little et al [4] developed delay-based and bandwidthbased methods, respectively, to coordinate traffic signal timings in a corridor. Sheffi et al [6] developed a traffic signal timing optimization model considering equilibrium assignment. The combination of traffic control and traffic assignment in the case of emergency evacuation was considered in Marciano et al [7]

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