Subarea Analysis Using A Travel Demand Model and A Microscopic Traffic Simulator

Abstract

This research proposes a method and related software tools to accomplish subarea analysis for transportation projects. The method proposed in this thesis takes output from the travel demand model and focuses in with a microscopic traffic simulation package to simulate traffic movements. Subarea simulation fills the project-level traffic forecasting gap that exists between isolated transportation projects and network impacting projects.

The method uses two software packages to structure and systematize the subarea analysis process. TransCAD is a travel demand modeling package capable of producing and evaluating regional or urban travel demand patterns. VISSIM is a microscopic traffic simulation package designed to simulate and evaluate traffic over a subarea network. The proposed method illustrates how daily traffic volumes from regional travel demand models are usable for localized project impact studies that require hourly volumes. The method represents an important step in the evolution of planning by blending a travel demand model for forecasting with a simulation model for traffic operations.

A case study of two north-south bypasses around Pittsboro, NC, describes the application of the subarea analysis method with travel demand modeling and microscopic traffic simulation. The evaluation of the simulation output data shows that either of the north-south bypasses performs better than the existing north-south highway that runs through the center of town. Both proposed bypasses create positive and negative traffic impacts. The eastern bypass best enables through movements, while both bypasses facilitate movement through the traffic circle. The case study demonstrates that the proposed methodology evaluates different project alignments. The case study results and the functionality of the microscopic traffic simulation software promise similar successes with other case studies involving signal optimization, intelligent transportation systems, and alternative traffic controls such as roundabouts.