The effect of ignoring routes when locating depots

In physical distribution the location of depots and vehicle routes are interdependent problems, but they are usually treated independently. Here the authors evaluate the effect of ignoring routeing when locating depots by using a two stage process (location and routeing). Using data from standard problems, it is shown that the best solution after the location stage does not necessarily generate the lowest cost solution after the routeing stage. This feature is found both when the best locations obtained from a variety of methods are compared, and when a single method is evaluated for different numbers of depots. A sensible way to determine the best combination of methods used in location and routeing is proposed.