Signal Timing Optimization of Oversaturated Isolated Signalized Intersection Considering Temporal Oversaturation Severity Index

Abstract

This study focuses on the development and application of a queue-based custom signal optimization model (Q-SOM) to an isolated intersection in managing traffic at oversaturated conditions. The key parameter to this model is the Temporal Oversaturation Severity Index (TOSI) which is characterized by a residual queue at the end of a cycle. The traffic signals are timed such that green time wasted is minimized by reallocating these from unsaturated phases to serve oversaturated ones, reducing the residual queue. The Q-SOM algorithm is applied to a calibrated and validated microsimulation model to evaluate its effectiveness using the following MoEs: intersection throughput, average stop delay, total network travel time, average speed, and average delay. Depending on the constraints and configurations applied to the algorithm, Q-SOM can significantly improve performance compared to a prevailing fixed signal control, and an optimized signal control using the critical movement analysis method (CMA).