Distribution companies that serve a very large number of customers, courier companies for example, often partition the geographical region served by a depot into zones. Each zone is assigned to a single vehicle and each vehicle serves a single zone. An alternative approach is to partition the distribution region into smaller microzones that are assigned to a preferred vehicle in a so-called tactical plan. The moment the workload in each microzone is known, the microzones can be reassigned to vehicles in such a way that the total distance traveled is minimized, the workload of the different vehicles is balanced, and as many microzones as possible are assigned to their preferred vehicle. In this paper we model the resulting microzone-based vehicle routing problem as a multi-objective optimization problem and develop a simple yet effective algorithm to solve it. We analyze this algorithm and discuss the results it obtains. 
Multi-objective microzone-based vehicle routing for courier companies: From tactical to operational planning