High-resolution sensing of urban traffic

Cities do not collect the high-resolution (HR) traffic data needed to evaluate and improve roadway operation. This paper describes a HR system called SAMS (Safety and Mobility System) that detects and records the lane, speed, signal phase and time when each vehicle enters and leaves the intersection; fuses these sensor events to estimate the intersection traffic state in real time for use by signal controllers; and archives the time series of traffic states to produce reports of vehicle counts and turn ratios, saturation rates, queues, waiting times, Purdue Coordination Diagram, and level of service (LOS); red light, speed, and right-turn-on-red (RTOR) violations, and vehicle-vehicle conflicts. The reports can be used to evaluate the performance of the current road operation and to improve traffic control.