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Thesis (M.S.)—University of Nebraska—Lincoln, 1982. Department of Civil Engineering.


Copyright 1982, the author. Used by permission.


The objective of this study is to evaluate the need for calibration of parameters “α” and “β” in the platoon dispersion model of the TRANSYT (Traffic Network Study Tool) program. Specific objectives include a study of the effect of calibrated papameters “α” and “β” on stops and delays predicted by the TRANSYT program and a determination of whether or not the stops and delays predicted by a calibrated TRANSYT program have a better correlation with those measured by the detectors on the street than do the stops and delays predicted by a noncalibrated TRANSYT program.

A platoon dispersion study was conducted to measure the profiles of traffic flow behavior between intersections and to calibrate the parameters “α” and “β” of the traffic flow model. A set of TRANSYT runs were conducted for two arterial street networks for both before and after the implementation of timing plans designed using the TRANSYT program with and without calibrated “α” and “β”. Then stops and delays predicted by TRANSYT were compared with those measured by detectors on the two streets.

Overall, based on findings of the study, it was determined that there is a need for calibration of “α” and “β” in the traffic flow model of the TRANSYT program. The calibration of these parameters was found to significantly reduce stops and delays. Also calibration significantly improved the correlation between stops and delays predicted by TRANSYT and those measured by the detectors. The transferability of calibrated parameters from one street to another was found to be limited due to the fact that no indication of significant improvement was found with “α” and “β” calibrated for one street were applied to the other.

Advisor: Patrick T. McCoy