Prioritization of bridges in urban transportation networks during an evacuation in crisis Case study: the city of Isfahan transportation network

The urban transportation network is an essential component of our daily life in modern communities. This network is vulnerable to natural and humanitarian disasters. Its degradation may lead to large negative impacts on the economic efficiency of such communities. A bridge collapse or a terrorist attack may severely reduce accessibility and increase travel time significantly in urban transportation networks. Therefore, evaluation of the impacts of different crises on a transportation network will help to reduce such degradations. On the other hand, the repair and maintenance of highway bridges, as the most critical component of the transportation networks, imposes a large portion of total annual maintenance costs, and usually due to lack of unlimited budget, this money has to be spent based on the importance and/or priority of the bridges in the network. The current study aims to prioritize the critical bridges during an evacuation in crisis conditions in urban transportation networks. The rank of each bridge is based on the difference in the total network travel time before and after that given bridge is eliminated from the network in such condition. The bridge that by its elimination causes higher travel time is considered more critical. This proposed method is applied to 78 bridges in the city of Isfahan traffic network. According to the results with proper scenarios, Andishe, Shahid Amini and Shahid Kharazi bridges rank as the top three with the highest traffic volumes, while Andishe, Imam Khomeini and Pol-e-Vahid bridges are the top three based on the proposed travel time method.