Robust Investment Decisions for Highway Capacity Expansions

Transportation assume no liability for the contents or use thereof. The contents do not necessarily reflect the official views or policies of the State of California or the Department of Transportation. This report does not constitute a standard, specification, or regulation. 2 Abstract In this report we present a methodology to decide capacity expansions for a transportation network that finds a robust solution with respect to the uncertainty in demands and travel times. We show that solving for a robust solution is a computationally tractable problem under conditions that are reasonable for a transportation system. For example, the robust problem is tractable for a multicommodity flow problem with a single source and sink per commodity and uncertain demand and travel time represented by bounded convex sets. Preliminary computational results show that the robust solution can reduce the worst case cost by more than 20%, while incurring on a 5% loss in optimality when compared to the optimal solution of a representative scenario.