Identifying critical areas in urban road networks: A grid-based approach considering route redundancy

With the frequent occurrence of disruptive events in cities, identifying weaknesses in urban road networks has received great attention. Different from existing studies on link or node disruptions, this paper addresses area-covering disruptions and identifies critical areas in urban road networks. Considering the impact of area-covering disruptions on travelers’ route choices, we adopt the concept of route redundancy between each origin–destination (OD) pair to measure the criticality of each area with respect to the entire network. Compared with typical topology-based indicators, the route redundancy-based indicator considers not only network topology but also travelers’ OD-level route choice preferences. To simulate area-covering disruptions, we use a grid-based approach to analyze the impact caused by the blockage of each grid cell. Furthermore, we determine the appropriate range of cell sizes and investigate its impact on identification results. Two case studies in the road networks of Winnipeg, Canada and Kunshan, China reveal scale-dependent spatial distribution patterns of area criticality. The proposed approach can identify critical areas that might be overlooked by straightforward indicators such as road network density.