A refuse company has a service contract for trash collection in a metro Atlanta neighborhood. This is a relatively large subdivision with approximately 4000 homes; streets are both one- and two-way and pickup occurs once weekly (every Tuesday).

Currently, the company assigns three trucks to the subdivision with all entering at a fixed point (x) and departing by an exit point (y, which is different than x) after their work is completed. While no single or even pair of trucks has enough combined capacity to completely service the neighborhood, the capacity of all three will indeed suffice; that is, all three must be used in some configuration.

Your objective is to find a fixed route for each vehicle so that the least combined travel distance (considering all trucks) is driven and the following restrictions are met: (i) no vehicle capacity is exceeded, and (ii) each street is traversed, adhering to direction if necessary, at least once.