Vulnerability Assessment of Urban Intersections apropos of Incident Impact on Road Network and Identification of Critical Intersections

One of the major challenges in a transportation network management program is responding to traffic incidents such as traffic crashes, disabled vehicles, spilled cargo, road debris, and so forth, at or near intersections. Intersections are vulnerable with respect to their susceptibility to incidents, therefore, it is important to assess their vulnerability to identify critical intersections for preparing traffic incident management strategies. In the present work, vulnerability of an intersection was measured in relation to the incident impact on surrounding road network using average aggregate network delay. Taking the case study of an urban arterial road network in Kolkata city, a methodology was demonstrated to assess the vulnerability of intersections using traffic microsimulation during peak and off-peak periods. A traffic microsimulation model was developed for this purpose and different incident scenarios were simulated to assess the vulnerability of various intersections. The intersections were then ranked in order of their vulnerability. Some key factors governing vulnerability of intersections were identified and an expert opinion survey was also conducted to assess the location-specific relevance of those factors for both peak and off-peak hour conditions using fuzzy analysis. Based on the analysis of expert opinion data, intersections were also ranked as per their vulnerability for comparative purposes. The rankings of intersections as obtained from traffic microsimulation and expert opinion analyses were found to be in agreement in the present context. However, traffic microsimulation as an approach is preferred over expert opinion because of its inherent strengths for vulnerability assessment and identification of critical intersections.