USING DECOMPOSITION IN LARGE-SCALE HIGHWAY NETWORK DESIGN WITH A QUASI-OPTIMIZATION HEURISTIC

The highway network design problem deals with the selection of links f rom a base network to facilitate the flow of vehicles from origins to destinations. A proper selection of links requires a balance between m inimization of travel costs from origins to destinations and minimizat ion of costs incurred in building or improving links in the network. L ink construction costs are usually minimized as a part of the objectiv e or constrained by budget availability. National or regional highway network design problems require excessive amounts of computing time, i f solved to optimality. This paper presents a variation of the Modifie d Quasi-Optimization (MQO) heuristic developed by Dionne and Florian ( 1979). The proposed algorithm solves a large network design problem by decomposing it in a sequence of smaller problems. Additional savings in computation time are achieved by limiting the search in the MQO heu ristic to a well-designed set of paths for each OD pair. These paths a re generated to suit the network design problem and differ from the K- shortest paths for the OD pairs. The combined use of decomposition and a limited set of paths allows the proposed heuristic to address reali stic network design problems. Numerical experience with a problem invo lving 6563 nodes and 9800 two-ways links is reported. (C) 1998 Elsevie r Science Ltd. All rights reserved.