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472840-00044-1 Report Abstract

Real-time Calibration of Platoon Dispersion Model to Optimize the Coordinated Traffic Signal Timing in ATMS Networks

Lei Yu, Texas Southern University, June 1999, 51 pp. (472840-00044-1)

Vehicles form platoons at the exit point of a given traffic signal, which will disperse while they progress along the link towards the next downstream traffic signal. The platoons may disperse either more quickly or slowly depending on the actual road geometric and traffic conditions between the two adjacent intersections of interest. The adequate modeling and description of the platoon dispersion behavior ultimately affect the quality of the coordinated traffic signal timings. At present, the most widely used modeling method of platoon dispersion is the TRANSYT’s macroscopic platoon dispersion model in which the determination of its major parameters is based on the empirical values. This report presents a methodology for calibrating the platoon dispersion parameters in the TRANSYT’s platoon dispersion model, which is based on a statistical analysis of link travel time date rather than more traditional goodness-of-fit tests between the observed and the projected vehicles’ progression patterns. Specifically, the platoon dispersion parameters are made explicit dependent variables of the average link travel time and the standard deviation of link travel times. The proposed technique is suited for applications in advanced traffic management systems (ATMS) networks where the required link travel time data could be obtained on a real-time basis. The calibration of platoon dispersion parameters using the proposed technique for the field collected data has shown that platoon dispersion parameters are indeed different, even on the same street but with different travel times. This conclusion confirms the need for calibrating platoon dispersion parameters on a link specific basis.

Keywords: TRANSYT, Platoon Dispersion, Calibration Signal Control, Traffic Simulation