Calibration of Microsimulation Models forMultimodal Freight Networks

® The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation University Transportation Centers Program, in the interest of information exchange. 16. Abstract This research presents a framework for incorporating the unique operating characteristics of multi-modal freight networks into the calibration process for microscopic traffic simulation models. Because of the nature of heavy freight movements in US DOT Region VII (Nebraska, Iowa, Missouri, Kansas), the focus of the project is on heavy gross vehicles (HGV), or, trucks. In particular, a genetic algorithm (GA) based optimization technique was developed and used to find optimum parameter values for the vehicle performance model used by " Verkehr In Staedten-SIMulationmodell (VISSIM), " a widely used microscopic traffic simulation software. At present, the Highway Capacity Manual (HCM), which is the most common reference for analyzing the operational characteristics of highways, only provides guidelines for highway segments where the heavy vehicle percentages are 25 or less. However, significant portions of many highways, such as Interstate 80 (I-80) in Nebraska, have heavy vehicle percentages greater than 25 percent. Therefore, with the anticipated increase in freight-moving truck traffic, there is a real need to be able to use traffic micro-simulation models to effectively recreate and replicate situations where there is significant heavy vehicle traffic. The procedure developed in this research was successfully applied to the calibration of traffic operations on a section of I-80 in California. For this case study, the calibrated model provided more realistic results than the uncalibrated model (default values) and reaffirmed the importance of calibrating microscopic traffic simulation models to local conditions. 17. v List of Figures Figure 2.1 Freight-truck highway volumes 2005 and 2035 6 Figure 2.2 Resistance forces acting on truck 7 Figure 2.3 Trends in weight-to-power ratios of trucks from 1949 to 1984 13 Figure 2.4 Relationship among the forces available to accelerate, available tractive effort, and total vehicle resistance 14 Figure 2.5 Observed time versus distance curves for acceleration to high speed from a stop by a tractor-trailer truck 17 Figure 2.6 Overview of simulation process 20 Figure 3.1 Observed speed versus time curves for trucks 31 Figure 3.2 Observed truck length distribution at Emeryville test bed 35 Figure 3.3 Truck traffic composition used in VISSIM model 37 Figure 3.4 Truck weight distribution …