Abstract
This thesis describes the development of a new geographic information system (GIS) tool to evaluate the safety effectiveness of roadway safety projects. The tool calculates four standard safety performance measures and compiles the results into a report. The tool was demonstrated with a case study of nineteen projects that began between 2013 and 2015 and were completed by 2016 throughout the state of Idaho. Ten of the projects experienced reductions in crash frequency; eleven experienced reductions in crash rate; eight experienced reductions in annual economic cost; and ten experienced reductions in severe crash proportion. Four projects experienced reductions in all four safety measures.The thesis also introduces a new safety performance measure based on the concept of expected utility. The new measure, called expected cost, was demonstrated in three example applications: network screening, safety effectiveness evaluation, and route choice navigation. For network screening, ten intersections and ten segments were ranked according to their expected costs and compared to rankings formed by the four standard measures. Two intersections and two segments were then analyzed using expected cost to test its performance in safety effectiveness evaluation. The results were again compared to those generated by the standard performance measures to see if expected cost offers a new perspective in this application. Lastly, the expected cost was used to calculate routes that optimized safety rather than travel time.