Environmental Engineering Reference
In-Depth Information
Fig. 11 Readjustment of the reference customer and the previous customers until reaching a
customer that is located inside the restricted zone
Fig. 12 Illustration of the
displacement between a
customer located inside the
restricted zone to another one
located outside
2.2.3 Leaving the Restricted Zone
If the vehicle is now traveling from customer i, located inside the restricted zone,
to customer i ? 1, located outside, we can again distinguish between two parts of
the trajectory, one inside the restricted zone (D d ) and the other one outside (D f ), as
shown in Fig. 12 .
The possible cases to contemplate now, depending on the time window, are
very similar to the previous scenario. For instance, if the time window is open
when reaching customer i ? 1, the displacement follows the general case proce-
dure, as shown in Fig. 13 .
However, the time window may close on the vehicle during the displacement,
which happens when the vehicle leaves the restricted zone after t vc . For instance,
the displacement depicted in Fig. 14 is valid, and is treated like the general case,
whereas the one in Fig. 15 is not.
In this unfeasible case, the procedure needs to readjust the arrival time to
customer i, moving it back until the time window is open again (see Fig. 16 ).
Then, like in the previous scenarios, all the customers visited before I and which
are not located inside the restricted zone would also be moved back in order to
visit them while the time window is closed and thus save time in the overall route.
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