Date of Award

6-2014

Degree Name

Master of Science in Engineering

Department

Civil and Construction Engineering

First Advisor

Dr. Jun-Seok Oh

Second Advisor

Dr. Valerian Kwigizile

Third Advisor

Dr. Joseph W. McKean

Access Setting

Masters Thesis-Open Access

Abstract

This study investigates the factors which affect the safety of non-motorized transportation within the influence area of intersections to enhance development of safety performance functions (SPFs). The scope of this study is limited to the four Michigan cities of Ann Arbor, East Lansing, Flint and Grand Rapids. Due to the current lack of research regarding the appropriate size of the influence area, this study investigates the distance of crashes relative to the center of 148 intersections to identify the most probable area of influence for different crash types. For motorized and non-motorized crashes, 240 ft. and 137 ft. are proposed, respectively. The proposed area of influence is adopted for developing the SPFs. Crash data (from 2008 to 2012) and geometric and exposure characteristics of the intersections are investigated to develop the SPFs. Results of the pedestrian SPF reveal that increased exposure, more left-turn lanes, presence of on-street parking, and bus stops at the intersections increase pedestrian crash frequency, while presence of speed signs decrease the number of pedestrian crashes. Results of the bike SPF demonstrate that exposure, presence of bicycle lanes, presence of bus stops and the number of left-turn lanes at intersections are positively associated with bicycle crashes. A structural equation model (SEM) is developed to decipher complex interrelationships among the variables affecting bike crash frequency. Results show that although the presence of bicycle lanes is significant in increasing bicycle crash frequency, bike lanes are correlated with bicycle volume, thus bicycle lanes do not endanger bicycle safety.

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