The Dutch road network is, like many other road networks in the world, congested in the morning and evening peaks. The locations of congestion are quite often the same; this makes it relatively easy to take the delay of this regular congestion into account when planning a trip. However, as a result of unforeseen disturbances, also unexpectedly large delays occur. A data analysis of a single incident on an off ramp showed that small incidents can block a large part of a motorway network for many hours. Many individual travellers experience an unexpected delay of more than one hour as a result. Incidents like this happen quite often. In the future, the effects of those incidents will likely become larger, because the spare capacity in both space and time will be reduced as a result of growth in demand in urbanized areas, if no measures are taken. Our simulations indicated that the costs of vulnerability in 2008 were ranged between €275 million and €1.2 billion. If no measures are taken, by 2030 these costs might increase to between €900 million and €4.1 billion. These results suggest that it would be beneficial to implement robustness measures to reduce these costs. In order to reduce the vulnerability, different measures need to be taken that make the road network more robust. Our main objective was to develop a network design method for designing road networks that are robust against incidents which is applicable to real sized networks and can be used in practice. We focused on the robustness of the road structure. This can be seen as a first step towards the development of a robust mobility system (including public transport and multimodal trips) in which also non-structure related measures are taken. (Author/publisher)
Abstract