Shock Waves and Speed Peak Propagations in Stop and Go Car-Following Conditions within Short Distances

摘要

This paper presents the study of a car-following platoon movement under stop and go conditionsgenerated in short distances. The car-following platoon consisted of ten vehicles with theleading vehicle initiating perturbations on a test-track. Trajectory data on each vehicle wasrecorded with GPS. Vehicle movements varied based on the speed patterns initiated by theleading vehicle with each data set including a cycle of stop, acceleration, car-following,deceleration, and complete stop. The car-following platoon was forced into moderately hardacceleration and deceleration in a short time for a hypothetical intersection or freeway bottleneck.Throughout the vehicle trajectory data, shock wave propagations were investigated. Shockwaves are normally used for stop and go conditions at a fixed location, however this studyfocused on observing repeated shock waves created by the same group of drivers repeatedly. Aswell as studying the vehicle trajectories in microscopic level, speed wave propagations amongthe vehicles were also studied considering asymptotic stability in the car-following platoon.After carefully reviewing the stop and go vehicle trajectories, it was found that there is adiscrepancy between actual vehicle trajectories and hypothetical uniform traffic flows in theshock wave theory derived from the macroscopic traffic model especially in the case of shortdistances. Findings and considerations are summarized at the end of this paper.