Let us consider a six flows OD structure in a system with three nodes (see figure 1)
connected by three links of length dij. Note that for this simple physical network, the choice
of a service structure is conveniently coincidental with the choice of a route structure
because there is no decision on link sequence. We will keep the simplifying assumptions of
the previous section, namely the sequential loading/unloading procedure and known values
of K, mand v. As explained earlier, our goal in the first stage is to find cost functions that
are conditional on the route structure. Let us begin with a general cyclical counterclockwise
structure (figure 2a), which implies the use of one fleet only. In this case, vehicle
load size on each segment of the network k12, k23 and k31, are defined by