User cost customization for a Florida bridge management system

Bridge Management Systems (BMS) are tools developed to help decision makers to prioritize projects that gives the highest benefit/cost ratio, where benefits are road user cost benefits. They are identified by the savings achieved in not spending travel time (TT) and vehicle operating costs (VOC) doing a detour, and reducing the risk of bridge related accidents. The state of Florida plus 38 states adopted the BMS Pontis to manage their bridge inventory. The hypothesis of this dissertation is that values benchmarked from other areas are not suitable to replicate the Florida reality. In order to prove this hypothesis a multi-step methodology was used including bridge-related accident cost using data from 11,332 bridge related accidents which occurred in 1996, sensitivity analyses, using 524 bridges under 39 different scenarios, modeled by Pontis-BMS version 3.4. The original user cost default values in Pontis are: $37,600 for each bridge related accident (Ca); $0.25 per kilometer for VOC costs (Cv), and $19.34 per hour for travel time (Ct). The findings of this research show the need to raise the Pontis-BMS, user cost default value rates to 45.05, 24.0 and 16.6 percent respectively for accident costs, VOC per kilometer costs and travel time values. The new values are $68,404.39 for Ca; $0.3138 for Cv, and $22.55 for Ct. The Project Attractiveness Index (PAI), measured by the benefit/cost ratio increased 25.96% with the use of the new user cost parameters. Sensitivity analyses showed that detour per kilometer is the most sensitive parameter, followed by the detour per hour, and finally the average bridge related accident cost parameter. Using the new default values in place of the old ones, deficient bridges that are related with accidents receive a higher prioritization order to be fixed, giving to decision-makers the possibility to reduce bridge accident risk.