Robust Design and Evaluation of Transportation Networks with Equilibrium Under Demand Uncertainty
Jennifer Duthie and S. Travis Waller, University of Texas at Austin, October 2006, 57 pp. (167556-1)
As long-term forecasts of origin-destination (O-D) travel demands are inherently uncertain, future network performance cannot be predicted with certainty. Neglecting the uncertainties present can result in inaccurate measures of network performance that may lead to incorrect policy decisions. This work relaxes the assumptions of determinism and independence of O-D demand in solving user equilibrium assignment. Insight is presented into the impacts of these assumptions through numerical analyses, where demand takes on various types of normal and lognormal multivariate distributions. The results indicate that incorrect assumptions of independence can, depending on the actual relationship between demands, lead to significant over- or under-estimation of network performance and incorrect network improvement decisions.
Keywords: Origin-Destination, Travel Demand, Travel Patterns, Transportation Network Performance
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