An algorithm for capacity expansion of an urban road network

An heuristic procedure based on cost-benefit concept is presented for capacity expansion of an urban road network. The procedure involves alternatively solving a capacity variable-outer problem and a flow variable-inner problem. The approach employs a modified travel time function which renders the outer problem into a simple linear programming structure amenable to solution by simple marginal analysis. The inner problem as a traffic assignment problem is capable of solution by known efficient procedures. The proposed approach is illustrated through a numerical problem.