Keywords: road networks, reliability measures, prediction models, impact assessment, risk management, transport networks, disruption, travel time unpredictability, just-in-time, JIT production, natural disasters, transportation, critical infrastructures
Road network unreliability: impact assessment and mitigation
Road transport network reliability has recently become important, with the increasing emphasis on 'just-in-time' production methods and reducing the impacts of natural disasters (e.g., earthquakes, tsunamis). This has led to increased efforts to mitigate the impacts of disruption of road transport networks, and the inclusion of changes in network reliability in economic appraisals of road network improvement proposals. This paper discusses the sources of unreliability, and the relative merits of alternative measures of reliability and models for predicting reliability. Methods for assessing and mitigating the impacts of degradation of inter-urban and urban road networks, and for estimating the economic value of reducing travel time unpredictability, are described. The paper also outlines research into the resilience of road networks and the users/organisations which rely upon them. The paper focuses on fundamental issues and methodological problems, and concludes that several such issues and problems are yet to be resolved.