Guest Editorial: Reliability and Emergency Issues in Transportation Network Analysis

Abstract

Transportation networks are exposed to various sources of uncertainty in the real world. The main sources of uncertainty include demand and supply variation. The variation in demand may be caused by the day-to-day fluctuation of the travel demand (which can be recurrent or a special case) or by the variation in the travelers_ behaviors. On the other hand, the supply variation may be a temporary or permanent one or short or long term degradation of link performance caused by different external factors (e.g., natural disaster or variation in on-street parking over the time period). In particular, under some sporadic conditions the network can be considered as being operated under the emergency condition (mainly dealing with major natural or man-made disasters). With all these uncertain environments, the travelers and network planner faces uncertainty in the network performance or level of service. The impacts of uncertainty and unreliability of the transport network can be listed from those related to our day-to-day life (late arrival or higher level of redundancy in departure time), major loss in economic efficiency of the logistics and transport system, or even a threat to national security and safety. In the light of these potential impacts and recent threats to the stability/security of the network (due to both recurrent and sporadic circumstances), several governments and organizations have defined the issue of network reliability and operation under the emergency condition as the main theme of national transport policy. In order to cope with these problems, one needs to understand several aspects of the effect of uncertainties related to the network operation, short and long term planning, evaluation of network reliability, or travelers_ behaviors under certain condition. Given the wide range of research issues that arise and the level of practical significance of this issue in the future, this special issue gathers ten papers reporting Netw Spat Econ (2006) 6: 169–172 DOI 10.1007/s11067-006-9278-7