Traffic delays estimation in two-lane highway reconstruction

An increasingly important issue, as congestion levels increase more and more, is that freeways become subject to rebuilding and restructuring when traffic cannot be re-routed. It has already been asserted that traffic simulation provides a better approach to the analysis of freeway reconstruction than the traditional Highway Capacity Manual. In fact the users' delay on freeway under reconstruction, when traffic flow is under capacity, cannot be evaluated by the standard HCM procedures. The impacts on existing traffic patterns are significant: the costs of delay and safety suffered by users even for low flows requires to take adequate management actions. From the point of view of direct reconstruction costs, every attempt to reduce user cost brings an increase in the direct costs of rebuilding. So there is a clear trade-off between reducing direct costs and mitigating the costs to travellers and economic activities. The object of this paper is to allow the evaluation of the delay that is suffered by the users of two-lane freeways when only one lane is available. The delays for different flow levels and different lengths of the reconstruction area are evaluated with the use of a tailored new developed microscopic traffic simulation model.