Direct search algorithms for truck-dispatching problems

Abstract In this paper problem-solving procedures for solving a number of truck dispatching problems have been discussed. In Part I discussion has focused principally on single-route problems and has included a range of problem characteristics such as weight or volume limits on the carrier, limits on the maximum number of stops allowable per trip, earliest or latest acceptable times for the delivery of items at particular destinations, partial deliveries and optional deliveries. All of the problem-solving procedures developed have been reliable in the respect that when carried out to completion they guarantee the discovery of an optimal solution when one exists. Moreover, they have all been direct algorithms which proceed first to the discovery of a feasible solution and then to successively better and better feasible solutions until ultimately one is discovered which is shown to be optimal. These procedures are thus well suited for use in adaptive systems wherein it is desirable or mandatory that the amount of problem-solving effort expended on a particular problem in a given instance be made dependent on environmental considerations and/or on the economic value of the problems currently in the system and the problem-solving effort. With minor modification these same algorithms can be used to determine all optimal solutions having a value within a specified range or percentage of the optimal value, a specified number of the most preferred solutions, and so on.