SOME ISSUES RELATING TO THE OPTIMAL DESIGN OF BUS ROUTES.

The paper presents a discussion of some issues relating to the design of minimum cost bus routes serving a multiple origin-multiple destination trip distribution. It is shown that the objective function (total cost) is a nonconvex function of the assignment; the higher the demand for trips on a route, the better is the service that one can provide. One consequence of this is that a square grid of straight line bus routes is not likely to be an optimal geometry even under highly idealized conditions. ″Good″ geometries are more likely to focus routes onto a single street and past a common junction.