Navid Khademi - Assistant professor, School of civil engineering, University of Tehran
Amirmasoud Almotahari - M.Sc. student of highway and transportation engineering, University of Tehran
Mostafa Bababeik - Ph.D. student of highway and transportation engineering, University of Tehran
Kambiz Behnia - Associate professor, School of civil engineering, University of Tehran

Transportation system has been considered as one of the fundamentals in socioeconomic development in countries. Concept of vulnerability in transportation systems, emerged as amajor new area of interest in transportation planning research recently. In traffic networks, robustness which may be taken as conceptually the inverse of vulnerability, has been determined in order to investigate serviceability reduction and demand changes due to it;This highlights the importance of this topic in local, regional and national transportation policy and planning. The change in the network’s total cost is a measure proposed in this paper to consider consequences of one or more links failures in a transportation network.Vickrey’s bottleneck model is used in order to evaluate the network’s serviceability before and after abnormal conditions

Vulnerability of transportation networks, Bottleneck model, Departure time