Date on Master's Thesis/Doctoral Dissertation


Document Type

Doctoral Dissertation

Degree Name

Ph. D.


Civil and Environmental Engineering

Committee Chair

Harris, Roswell A.

Author's Keywords

Bicycle; Motor vehicle; Safety; Conflict; Intersection; Right turn


Cycling accidents--Kentucky--Louisville; Bicycles--Safety measures; Traffic accidents


The main purpose of this research was to find out the characteristics of bicycle-related crashes and improve safety and comfort for bicyclists around signalized intersections in Louisville, KY. At first, the benefits of bicycling for accessibility, health, environment and traffic were discussed. Plans made by a number of states, regions and local governments for encouraging people to use bicycles as an alternative to motor-vehicles were introduced. Emphases were put on the introduction of the Louisville Metro Bike Master Plan, which aimed to increase bicycling activity throughout all parts of Louisville by making it a fun, comfortable and accessible mode of travel, and to simultaneously reduce the number of cyclists killed and injured in crashes with motor vehicles. Second, an elaborative literature interview was made to look for the reasons which caused crashes between bicyclists and drivers. The conclusion was that a large percentage of bicyclists-related crashes happened at intersections. The most important reason for bicyclists-related crashes was drivers’ failing to yield when they were entering turning movements. Third, research for possible solutions which were used to improve safety for bicyclists was made. Studies which evaluated the effectiveness of those solutions were discussed. Fourth, in order to determine the characteristics of bicyclists-related crashes in Louisville, crash data of 10 years (from 2003 to 2012) was collected from the Kentucky Collision Analysis for the Public. Bicycle-related crashes in Louisville were most prevalent in the summer months, on weekdays and in the afternoon peak period in clear weather conditions. Turning-right was one of three highest possible pre-crash maneuvers in all bicycle-related crashes in Louisville The most important factor causing bicyclists-related crashes was motorists’ inattentiveness, or failing to yield the right-of-way to bicyclists. Bicyclists’ inattentiveness or failing to yield the right-of-way was also important for bicyclists-related crashes. Fifth, surveys were made four times to evaluate the effectiveness of a newly-developed countermeasure for bicyclists’ safety. The conclusion was that this countermeasure for bicyclists’ safety couldn't influence the distance from the curb where motor-vehicle crossed the stop bar. Most drivers preferred 4-6 feet away from the curb when they crossed the stop bar. This countermeasure for bicyclists’ safety could attract about 40% of drivers to cross the boundary between the bicycle lane and the traffic lane and to enter the right-of-way of the bicycle lane. More than 50% of drivers needed 60-100 feet to finish the process of entering the right-of-way of the bicycle lane from the adjacent traffic lane. In short this newly-developed countermeasure for bicyclists’ safety could greatly improve bicyclists’ safety at intersections by changing drivers’ right-turning movements. At last, some possible improvements for this new countermeasure were discussed to better this countermeasure in the future.