Microscopic Modeling of Control Delay at Signalized Intersections Based on Bluetooth Data

Bluetooth media access control (MAC) identification (ID) detection has been effectively used for near real-time traffic monitoring. Its continuous data collection capability by sampling actual traffic makes it feasible for permanent installation in the road with minimal cost and better data accuracy, both qualitatively and quantitatively. However, the delay calculated with simple matching of MAC IDs has some inherent errors due to the frequency hopping structure of Bluetooth detections. The detections of a Bluetooth device in a traveling vehicle can be thought of as random events varying in space and time. This article presents two models to calculate traffic control delay based on synchronized Bluetooth and global positioning system (GPS) probe vehicle data. The two models are based on the number of Bluetooth observed detections and the time duration between the first and the last detections. The proposed models were found to be more accurate than the existing practice and have the potential to be used for estimating intersection approach level-of-service (LOS) in near real time for evaluating and optimizing signal timing plans.