In order to force the NA VRP solver to produce a reasonable
solution without any anomalous sequence, the following
procedure was developed: In the first step, the VRP solver was
run with the selected orders to obtain an initial solution with
anomalous sequence. If there were prohibited turns at some
intersections, a setting to “allow U-turns only at dead ends”
was prepared to obtain a feasible solution. In the second step,
the sequence of orders from the VRP solver’s initial solution
was exported and joined with the orders input layer. In the
third step, the sequence was modified by using the ArcGIS
field calculator to correct sequencing errors. When the new
correct sequence was established, the VRP solver was run
again with the setting preserving this sequence and policy for
U-turns set to the option “allow U-turns at intersections and
dead ends”. With this approach, the problem of unreasonable
long travel time caused by anomalous sequencing described
by [6] was eliminated.