A Generalised Signal Timing Scheme at Isolated Intersections Considering Multi-Modal Pedestrian Crossings

EasyChair Preprint 15196

Abstract

Existing literature on signal optimisation mainly aims to improve the vehicle mobility by allocating green duration to typical phase structures (e.g., NEMA dual-ring, eight-phase structure). However, pedestrians with massive delays may prefer to jaywalk due to the inequitable treatment. This paper proposes a generalised signal timing scheme at an isolated intersection, which explicitly incorporates the benefits of vehicles and pedestrians in the objective function. Multi-modal pedestrian crossings is concerned, in which one-stage crossing (OSC) and two-stage crossing (TSC), together with shared and exclusive pedestrian phases appear in given platform. The general signal cycle may contain several sub-cycles. Low-demand phase could be skipped in sub-cycles and high-demand phase could have multiple right-of-way within the overall signal cycle. Over-saturated phases are allowed in sub-cycles. In this way, flexible phase sequence with sub-cycles, phase duration, and cycle length are optimised together to minimise the weighted average delay. The model is formulated as a mixed-integer non-linear programming (MINLP). To mitigate computational burden, we design an algorithm integrating Monte-Carlo tree search (MCTS) and spatial branch-and-bound algorithm with outer approximation, where the former determines the phase sequence and the latter optimises the phase duration. Our framework could achieve a nearly 51% improvement compared to classical four-phase model.

Keyphrases: generalised signal scheme, isolated intersection, pedestrian crossing, signal timing

@booklet{EasyChair:15196,
  author    = {Guang Wang and Lijuan Wan and Chunhui Yu and Wanjing Ma},
  title     = {A Generalised Signal Timing Scheme at Isolated Intersections Considering Multi-Modal Pedestrian Crossings},
  howpublished = {EasyChair Preprint 15196},
  year      = {EasyChair, 2024}}