Dissertation/Thesis Abstract

Critical Gap Acceptance Values in O'Fallon, Il for a Single-Lane Roundabout
by Tindall, Bill, M.S., Southern Illinois University at Edwardsville, 2020, 128; 27957962
Abstract (Summary)

This thesis reviews the concept of critical gap as a parameter within the stochastic modeling of a single lane roundabout and its adjustment to represent real world local conditions. Existing traffic conditions of a single lane four-legged roundabout in O’Fallon, Illinois, was modeled using VISSIM microsimulation software with traffic turn movement volumes. Field observations were made to obtain a critical gap measurement of the roundabout and reflect this within the modeling and compare the model to the observed traffic flow conditions. The VISSIM microsimulation software modeling results were found to be consistent with field observations for both modeling methods of conflict areas and priority rules. The default critical gap parameter used for single lane roundabouts is based on a limited site inventory from roundabouts within the United States of America. The outcome of this study determined a critical gap estimate of 4.2 seconds, specific to Southern Illinois. In addition, this study confirmed that VISSIM microsimulation software, with minimal calibration, can realistically estimate performance for a single lane roundabout in Southern Illinois.

Indexing (document details)
Advisor: Fries, Ryan
Commitee: Qi, Yan, Osouli, Abdolreza
School: Southern Illinois University at Edwardsville
Department: Civil Engineering
School Location: United States -- Illinois
Source: MAI 82/3(E), Masters Abstracts International
Subjects: Transportation, Engineering, Civil engineering
Keywords: Critical gap, Headway, Microsimulation, Roundabout
Publication Number: 27957962
ISBN: 9798672110721
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