Crisis Management of Highway Network under Earthquake Environment Hiroshi Wakabayashi

This paper presents the comparative study for improving connectivity reliability between using probability importance (Birnbaum’s structural importance) and criticality importance based on the reliability graph theory, i.e. connectivity reliability: It is important to keep highway network highly reliable for both normal and abnormal period. Network reliability can be improved effectively by improving the most important key link on the network. When such important link is once discovered, it enables to improve and maintain network reliability efficiently. For the indicator for discovering the key link, Birnbaum’s structural importance has been proposed so far. In series connected network, the least reliable link is chosen as the first priority link that should be improved and this result is rational as the practical and actual case. In parallel connected network, however, the most reliable link is chosen as the candidate link that should be improved, but this result is irrational, because under this decision making principle, the most reliable link would be improved more and more, and the less reliable link would never be improved. This paper presents these characteristics of Birnbaum’s structural importance after discussion of the significances of crisis management of transportation systems after disaster. Then this article proposes the Criticality importance as the better indicator and compares the network performances improved by both importance indicators. In addition, this paper addresses the criticality importance ca