Solving the optimal network problem

A heuristic method for solving the optimal network problem is proposed and shown to yield high quality results. Solution methods based on Branch-and-Bound techniques are also considered in some detail. The effects of making various approximations, when calculating lower bounds, is discussed and the concept of forced moves introduced. The various methods are applied to a series of problems which include networks with link construction cost not proportional to length and with trip demands tij not all equal.