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Abstract
State highway agencies (SHA) are tasked with maintaining, repairing, and replacing bridges to support the travelling public. These agencies need to develop programs that prioritize candidate projects in a manner that ensures that bridges are selected for maintenance, repair, and replacement at appropriate times and within budgetary constraints. To accomplish this, prioritization methods must be developed that utilize and appropriately weigh the desired measures and agency preferences to identify candidate bridges that, if selected, help a state highway agency (SHA) achieve performance criteria. Federal and state legislation provide guidance for national and statewide goals for transportation improvements, but SHA’s are tasked with establishing prioritization indexes to measure progress towards those goals in a manner that reflects agency preferences and risk attitudes. This thesis presents a portion of work required to support development of new prioritization indexes for bridge replacement, rehabilitation and preservation for the North Carolina Department of Transportation (NCDOT). To develop a list of proposed performance criteria and measures for bridge replacement, a review of published literature and a scan of SHA practices in the United States was performed to identify performance criteria and measures utilized by other agencies. The current prioritization index used by NCDOT, the Priority Replacement Index (PRI) was assessed to determine the current characteristics influencing this index, and to assess whether the current measures adequately meet legislative requirements and reflect agency preferences. An analysis of maintenance burden and maintenance needs data was performed to identify the best means of incorporating maintenance needs and maintenance burden into the prioritization criteria and measures and to justify their use. The current PRI is most significantly influenced by measures of average daily traffic, bridge condition, and some measures related indirectly to safety. Several characteristics included in the current PRI are essentially double-counted, while other characteristics that could be linked to current federal and state goals do not appear in the current PRI. Analysis indicated that both maintenance burden and maintenance needs are significantly linked to bridges previously prioritized by NCDOT, and are therefore performance criteria that should be used in the new prioritization index for bridge replacement. A new set of performance criteria that more adequately reflects federal and state goals is recommended to NCDOT for consideration. Finally, a survey has been developed that can be utilized by NCDOT to determine relative weightings of these proposed performance criteria and measures.