Methodology for evaluating importance of bridges based on detour simulations with virtual person trip data

<p>The methodology for assessing the importance of bridges as road structures based on virtual person trip data with protected personal information is proposed. The road network is modeled based on graph theory assuming the closure of the analyzed bridges. The increases in travel distance and time due to detours resulting from the bridge closure are calculated for each individual trip by performing path search based on Dijkstra algorithm. The importance of bridges under normal condition is quantified as the economic loss estimated based on the increases in travel distance and time. In addition, to investigate the importance of bridges in post-earthquake situations, the bridges intensively used as alternative routes to the damaged bridges are determined by performing detour simulation on the assumption that several bridges are simultaneously closed after an earthquake. The estimation results of applying the proposed methodology to the bridges located in Koriyama City demonstrate that the bridges with low traffic volume under the normal condition can have high importance in the road network. Moreover, it is founded that the bridges which would play an important role as alternative routes to ensure the traffic function in the analyzed area after an earthquake can be determined by the proposed methodology.</p>