An evaluation of the 'before and after' accident analysis process with four case studies on selected Tennessee state highway safety improvement projects

The "before and after" accident analysis technique presents a systematic method for evaluating the effectiveness of highway safety improvements. Through four case studies involving Tennessee Department of Transportation projects, this thesis describes the procedure of performing a "before and after" evaluation. Certain problems exist in the reliability and practicality of the traffic data that is fundamental for these studies. In addition, current "before and after" procedures as outlined by the TDOT Highway Safety Management Program require a great deal of time-consuming effort that could be eliminated by the incorporation of some computer automation features. Several improved methods of data management, including new technological advancements, were researched which would improve upon the overall reliability and speed of performing these evaluations. By improving upon TDOT's systematic "before and after" process, future engineers would see more a practical, expedient, and cost-effective method of project evaluation.