Date of Award

6-2016

Degree Name

Master of Science

Department

Civil and Construction Engineering

First Advisor

Dr. Jun-Seok Oh

Second Advisor

Dr. Valerian Kwigizile

Third Advisor

Dr. Ron Van Houten

Access Setting

Masters Thesis-Open Access

Abstract

While there have been many studies on engineering treatments for reducing traffic crashes or for improving intersection efficiency, few studies have been simultaneously taking both impacts into consideration. This thesis analyzed impacts of engineering countermeasures and determines when these countermeasures are cost effective with respect to the amount of traffic and the number of crashes. Both crash reduction and operational costs were compared for analysis. This study specifically investigated three countermeasures: changing from permitted to protected for a left-turn on minor approaches, leading pedestrian interval (LPI), and exclusive pedestrian phase (Barnes Dance). The general Safety Performance Functions (SPFs) from the Highway Safety Manual (HSM) were used to calculate the average number of crashes for all crash types; these values were set as the base. Crash Modification Factors (CMFs) available in Crash Modification Factor Clearinghouse for these countermeasures were used to calculate the number of crashes reduced. Meantime, traffic operational performances were evaluated through VISSIM microscopic traffic simulation. Both crash reduction and additional delay were compared with varying traffic conditions. There were trade-offs between safety and operational performances. In order to determine cost effective conditions, cost-benefit analyses at different traffic conditions were performed. This thesis provides a general guideline for decision makers to determine if the treatment options are cost-effective in both aspects.

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