American Society of Civil Engineers

Development of Analytic Models for Interchange Traffic Operations Based on Simulation Results

by F. Clara Fang, Ph.D., (Associate Professor, Department of Civil, Environmental, and Biomedical Engineering, College of Engineering, Technology, and Architecture, University of Hartford, West Hartford, CT 06117. E-mail:
Section: Overseas Papers, pp. 4298-4308, (doi:

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Document type: Conference Proceeding Paper
Part of: ICCTP 2011: Towards Sustainable Transportation Systems
Abstract: Interchanges are critical components of the highway network. They provide the connection between freeways and arterials. Common operational problems reported for interchange ramp terminals are inadequate capacity and queue spillback. There are currently no procedures in the Highway Capacity Manual 2000 or elsewhere for evaluating the operational effects of various interchange configurations, considering geometric, traffic and signal control characteristics. The objective of this study is to develop analytic operational models for capacity and quality-of-service analysis of interchanges. The development of the analytical methodology is primarily based on the calibrated simulation models. The reason for using simulation is that adequate samples of field data are not available, and it is prohibitively expensive to collect them for all types of interchange configurations. The research assessed several simulation models that were identified as capable of simulating all types of interchange ramp terminals and selected the most appropriate one to use for model development. Once a simulation model was selected, a variety of interchange configurations were simulated and selected measures of effectiveness were obtained. This paper discusses the development of two analytical models. They are lost time due to the presence of a downstream queue, and downstream queue at the beginning of each upstream phase. The model of lost time due to demand starvation was not entirely based on simulation results, was however also included in this paper.

ASCE Subject Headings:
Traffic management