Document Type
Thesis - University Access Only
Award Date
2021
Degree Name
Master of Science (MS)
Department / School
Civil and Environmental Engineering
Abstract
The number of modem roundabouts in the United States has increased exponentially since the first one was built in the I 990s. Now there are about 3000 roundabouts in operation in the US , including many being in service in Wisconsin. The Wisconsin Department of Transportation (WisDOT) has been using modem roundabouts to increase intersection efficiency and safety. According to WisDOT, by 2007 , over 60 roundabouts had been constructed in Wisconsin and about 140 have been planned . In spite of positive feedback on traffic safety from numerous studies in Europe or other states in the US , the safety performance of Wisconsin roundabouts has not been thoroughly evaluated and the impact of the roundabout operations on driver behavior is unknown. Therefore , it is necessary to conduct a comprehensive safety evaluation for roundabouts in Wisconsin , especially the ones that have been converted from conventional intersection control (e.g. signalized , two-way stop control , and all-way stop control) to a roundabout. In the study, 41 roundabouts with different traffic volumes , geometric factors , traffic control strategies, and years of construction were chosen as they have various years of history and represent Wisconsin roundabouts in general. The E mpirical Bayes (EB) method was applied in this study to est imate and evaluate the safety performance for roundabout conversion. Safety analysis was performed using Safety Performance Functions (SPFs) from the Highway Safety Manuel (HSM) and developed from the Wisconsin crash data , respectively. Intersection crash prediction regression models before roundabout construction were developed in order to estimate the crash trend and compare with the result from the HSM crash predictive methods. The evaluation result supports that the roundabout is a promising intersection safety countermeasure or an intersection design alternative that may enhance traffic safety by reducing the number of severe crashes.
Library of Congress Subject Headings
Traffic circles -- Wisconsin -- Safety measures -- Evaluation
Traffic safety -- Wisconsin
Publisher
South Dakota State University
Recommended Citation
Li, Shihan, "Safety Evaluation of Wisconsin Roundabouts Using the Empirical Bayes Method" (2021). Electronic Theses and Dissertations. 1949.
https://openprairie.sdstate.edu/etd2/1949
Rights Statement
