| The Purdue University Center for Road Safety (CRS) developed a tool called the Safety Needs Identification Program (SNIP) to help the Indiana Department of Transportation (INDOT) identify roads with safety needs based on an excessive number of crashes in certain categories (single vehicle, rear-end, run-off-road, etc.). The next fundamental question to address is optimal selection of relevant safety countermeasures under certain constraints given the specific crash problems and problem areas have been identified. This thesis tested and implemented a heuristic method developed by the director of CRS, Dr. Andrew Tarko and CRS Research Scientist Dr. Mario Romero to solve optimization problems. This method selects the best combination of available relevant safety countermeasures that offer the largest safety benefits under certain constraints where safety improvements are identified. After a thorough literature review of safety countermeasures, a catalog of safety countermeasures that are applicable and suitable for use in Indiana was developed. Also, the unit cost and conditions of each safety countermeasure were defined, and Crash Reduction Factors (CRFs) were proposed to predict the safety benefits to test and implement this heuristic method. The heuristic, after testing and implementation using several different case studies, was shown to be capable of producing a relatively good solution. This tool can improve INDOT's ability to identify cost-effective safety solutions while increasing the efficiency of their safety countermeasures. At the same time, this method also can substantially reduce the time and effort of INDOT engineers to calculate the cost-effectiveness of safety countermeasure. |
