Road Network Vulnerability Analysis: Case Study Considering Travel Demand and Accessibility Changes

Road network vulnerability analysis is helpful in the improvement of vulnerable links with proper maintenance investments and management strategies. This paper addresses issues that have received limited attention in past studies: estimation of travel demand after link disruption and analysis of accessibility variation. An activity-based model was used to estimate travel demand changes due to link closure, and link importance was evaluated using a set of vulnerability indicators. Accessibility changes induced by link closure are presented and discussed. Vulnerability analysis was conducted for the road network of the municipality of Dolo in northern Italy. Considering the spatial distribution of activities and trips, the results obtained with the activity-based model were more reliable than those obtained with the fixed demand model, which makes the unrealistic assumption of unchanged travel demand after network degradation. These findings are relevant for appropriate resource allocation strategies, which depend on correct link vulnerability analysis and ranking.