A STOCHASTIC USER EQUILIBRIUM PATH FLOW ESTIMATOR

The paper sets out a path flow estimator suitable for use in conjuncti on with urban traffic monitoring, control and guidance. Travel time fo r each link in the network is partitioned into undelayed travel time a nd delay. The links are assumed to be of two types. For the first type of link, an external estimate of flow and travel time over the estima tion interval is provided. The second type of link is characterised by a finite capacity, and delay is incurred where demand would otherwise be in excess of capacity. Demand is determined by a legit route choic e model. An equivalent convex programming problem is formulated and an iterative solution procedure is set out. The estimation of the disper sion parameter in the legit model is discussed, and a column generatio n method to avoid path enumeration is proposed. Diagnostic procedures and a number of other practical enhancements to the procedure, in part icular the incorporation of prior information on the relative magnitud es of origin-destination movements, are considered. (C) 1997 Elsevier Science Ltd. All rights reserved.