Traffic State Generation from Loop Detectors Based on Vehicular Trajectory Data

A loop detector is commonly used in detecting traffic states (flow, density, and speed). However, a loop detector's location and detection interval will have an influence on obtaining the traffic state. This paper proposes a method for generating the traffic state in a loop detector's mechanism based on the unique traffic flow (vehicular trajectories). In this paper, vehicular trajectories were first achieved based on vehicle space and time information obtained from a VISSIM model. Then, vehicle total travel time and distance were calculated in each detective space-time region. Finally, based on Edie's equation, the traffic state (flow, density and speed) was achieved. The proposed traffic state generation method was tested on Interstate 894, and a typical traffic flow fundamental diagram was successfully obtained. Compared with other methods, the proposed method can easily test the influence of loop detector settlement on traffic state accuracy.