Vulnerability of road network based on generalised travel time

Abstract

In this paper the vulnerability of a transportation network is defined from the perspective of the sensitivity of the transportation system against external disturbances. The generalised travel time is defined as the weighting of both the ratio of actual travel time to free travel time and the unreliability of the travel time. The reciprocal of generalised travel time taken as the utility function, the impact of external disturbances on the transportation system can be quantified. Meanwhile, the vulnerability model is established using the change rate of the utility index. The stochastic user equilibrium traffic assignment model is formulated on the assumption of minimisation of travel cost. Finally, the real road network of the city of Harbin in China is taken as an example to illustrate the applicability and efficiency of the proposed model. This approach can be used as a decision-supporting tool for identifying critical infrastructures in transportation management and planning.