Actuated Traffic Signal Performance Evaluation along Arterials using Wi-Fi Travel Time Samples and High-Resolution Traffic Signal Events Data

Abstract

Understanding traffic progression on arterials is critical for traffic signal control and urban traffic management. Traffic conditions are highly dynamic and evolve over time. Therefore, it is necessary to evaluate the arterial’s performance periodically to determine how well a traffic signal system is functioning. Arterial performance is conventionally evaluated based on travel time/speed collected via the probe vehicles. New approaches based on high-resolution traffic signal events have been proposed by a group at Purdue University, based on the Purdue Coordination Diagrams (PCDs). Both traditional arterial travel times/speeds and the PCDs can effectively reflect the level of traffic progression on arterials, while some practical questions have been raised about how to synthesize these two methods. The framework proposed in this paper integrates two types of performance measures by defining new multi-intersection coordination diagrams to examine traffic signal performance. The multi-intersection coordination diagram under different speeds can provide a straightforward tool for informed offset adjustments of actuated traffic signal coordination. In contrast, the state-of-the-practice traffic coordination performance analysis relies on fixed timings and empirical fine-tuning in the field. It is expected that these efforts can provide new insights to practitioners on how to use emerging traffic data better to improve the performance of actuated traffic signal operations on arterials.