Calibration of Platoon Dispersion Model with High-Resolution Signal Event Data

This paper presents a scalable methodology for automatically measuring platoon characteristics on links between signalized intersections. This methodology estimates the parameters of the Robertson dispersion model that characterize platoon travel time and platoon distribution along a link. The Kolmogorov-Smirnov statistical test was used to assess how well the model parameters characterize the platoon arrivals measured by the high-resolution event data. The methodology was tested on a corridor of nine intersections containing 18 coordinated links with data that were collected over a 3-week period. Quite consistent results were obtained for link travel times; however, in many cases the observed link travel times were faster or slower than the posted speed. The distributions of the dispersion parameter showed considerable variation across the analysis period as well as across the system. The test corridor presented an interesting situation in which shorter links experienced greater dispersion than did longer ones. The results suggest that platoon dispersion is more sensitive to driver behavior characteristics related to roadside environment than to distance traveled along a street. The methodology could provide a means of prioritizing links for coordination and for self-calibrating traffic optimization models and adaptive control systems. The scheme could be integrated easily into modern signal controllers with high-resolution event logging capabilities.