Risk assessment of highway bridges in Arkansas.

摘要

The U.S. highway system is a massive public investment. An overwhelming portion of all personal travels and freight transport across the nation depend solely on the highway system. Highways also play an essential role for emergency services and military movements. Therefore, security of the highway system is a primary responsibility of the federal and state governments.;The main objective of this study was to develop a methodological framework to identify, prioritize, assess, and manage the various possible risk scenarios for the highway bridges in Arkansas. The data for this research was supplied by the Arkansas Highway and Transportation Department. The supplied data consisted of detailed information about highway structures, including bridges, in Crawford and Washington Counties.;The research methodology consisted of a four-step process for prioritization of individual bridges based on their criticality and vulnerability components. Criticality of a bridge denotes its level of attractiveness for a planned negative incident while Vulnerability is a measure of how easy the task of carrying out the incident will be. The criticality component was determined based on selected bridge attributes, such as average daily traffic, structure length, and detour length. The vulnerability component was determined based on certain other bridge attributes, such as level of recognition, access control, and security level. The two components were plotted in a four-quadrant matrix to visualize the relative importance of the individual bridges. The bridges plotted in Quadrant 1 (upper right) were considered most important, while those in Quadrant 4 (lower left) the least important. Once the bridges were prioritized, the final step involved selection of countermeasures whose application could reduce the criticality and vulnerability components.;Based on the results of the study, the main conclusions are: (1) development of an effective risk assessment process is vital for protection of our indispensible transportation infrastructure (2) the ability to identify and prioritize the critical bridges will be of immense help to the policymakers for setting priorities and allocation of scarce resources (4) "traffic" and "detour length" are the two most important Criticality Factors for development of a comprehensive risk assessment framework, and (5) there is a need to upgrade the data collection protocol with inclusion of new data fields related to evaluation of criticality and vulnerability aspects.