Optimization of Crash Reduction Factors and Countermeasure Costs: A Case Study in D.C

The number of high crash intersections and the possible large number of crash types each with three severity levels account to a large possibilities of combinations. Corresponding to these are countermeasures that are applicable to each crash type and severity level. A countermeasure can be applicable to more than one crash type and severity levels; also more than one countermeasure can also be applicable to one crash intersections. Complicating the situation further are associated implementation costs and delays hours. Developing a methodology/system that considers all these variables simultaneously and identifies the most effective countermeasure(s) with the least cost is the challenge addressed in this dissertation.;This dissertation utilized crash data obtained from D.C. DOT. Literature reviews were conducted; FHWA, NHTSA, and state DOTs web sites were also used. Reviews of substantial state DOTs safety practices in general and the application of optimization in particular was also performed.;To properly handle the large number of variables and fulfill the multiple objectives concurrently, a multi-objective optimization method was employed. Four models with various combinations of the objectives were developed and processed.;This research promotes a new methodology outside the bounds of the current practice in most states and applies CRFs per severity level and more importantly to a unique dense urban area. The research also provides a methodology that is easily adoptable by any state, city, county, and municipality. The system generates feasible solutions with a combination of countermeasures that are effective, less costly to both the public (delay costs) and government (implementation costs).;Benefit-Cost analysis that is found commonly employed by the state DOTs is not necessarily the best answer nor appropriate to the multiple objectives that have to be fulfilled simultaneously. It should also be noted that, CRF is basic information required to use the system. It has been found that most states lack this information and should consider developing one.;Although this system identifies the best and the most cost effective countermeasures, the roles of the program manager by no means are diminished. The program managers still need to verify, field check and make final decision.