CONNECTIVITY VULNERABILITY EVALUATION BASED ON POTENTIAL ACCESSIBILITY CONSIDERING A REDUNDANCY OF ROAD NETWORK

Abstract

 Network vulnerability analysis considering only the influences of the event without considering its occurrence probability has been proposed recently. This study proposes the network vulnerability method of evaluating the influences of the closure of the road section while considering the number of distinct paths to enhance the connectivity of OD pairs. We formulate the mathematical problem of minimising total travel time while satisfying the number of distinct paths, and a potential accessibility measure is calculated based on the average travel time of the distinct paths. The critical section can be determined by the decrease of the accessibility measures by the closure of its section. We applied the model to whole road network of Gifu Prefecture, and evaluated the connectivity in the non-degraded condition as well as connectivity vulnerability under degraded situation. As a result, we could identify potentially critical sections by considering the number of distinct paths. Furthermore, we have found the sections whose accessibility is fine under the non-degraded situation but the accessibility decrease enormously by its closure, and this result suggests the importance of evaluating the network both connectivity evaluation under non-degraded situation and vulnerability evaluation.