RELATING SHOCKWAVE PROPAGATION SPEED AND TIME HEADWAY USING MICROSCOPIC ANALYSIS

摘要

Shockwave propagation speed and time headway are key incident precursors, and their timely estimation is critical in designing anticipatory elements of Intelligent Transportation Systems forfreeways. We analyze nine shockwaves and the microscopic characteristics of the vehiclesinvolved. Starting with video recordings from incidents on I-94, Minneapolis, vehicle trajectoriesare extracted. From the trajectories we define flow variables such as speed, deceleration,shockwave propagation speed, time headway and reaction time. Especially for shockwavepropagation speed and time headway we provide distribution fitting results for the delivereddatasets. Finally, a nonlinear relationship between shockwave propagation speed and timeheadway is presented.