A Bridge Management System (BMS) can be used for both storage of data and to provide decision making tools for maintenance, repair, and rehabilitation (MR&R) needs and cost forecasting. The North Carolina Department of Transportation’s (NCDOT) BMS currently includes bridge deterioration rates, agency costs, MR&R costs, and user costs to assist with prediction and prioritization of future needs. User costs are costs burdened by the public when a bridge is unusable by some portion of vehicles or is associated with bridge-related accidents. Key inputs required to compute user costs in NCDOT’s BMS include average daily traffic, detour length, percentage of vehicles detoured due to either weight or height, vehicle operating cost associated with detour, number of bridge-related accidents, frequency of bridge-related accident severities, and the costs of accidents. To provide accurate user costs for forecasting, these BMS inputs need to be regularly updated or enhanced as better methodologies for obtaining these inputs becomes available. In this work, updates and enhancements to NCDOT’s BMS user cost inputs and determination methodologies were identified, and new inputs were determined. An analysis of recent bridge-related accidents in North Carolina was performed to identify bridge characteristics most associated with bridge-related accidents and to produce an equation that predicts the number of bridge-related accidents for subsets of bridges based on data currently available in the BMS. A sensitivity analysis on user costs was also performed, indicating that user costs for NCDOT’s bridges are largely driven by costs due to bridge-related accidents.