In standard VRP problems, a node (pickup or drop-off) typically has a single time window defined by opentimets and closetimets. However, in many real-world scenarios, a location might be accessible during multiple disjoint time intervals. For example, a warehouse might be open for deliveries from 0800 and then again from 1400, closing for a lunch break in between.
In logistics operations, the strict time window of a order (which often corresponds to the location's opening hours) and the actual feasible time for a vehicle to arrive may not always align perfectly. This is particularly true when a location closes at a specific time, but the vehicle needs to arrive earlier to complete the service (e.g., unloading) before the facility closes.
The Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) extends the classic VRP by incorporating two key real-world constraints: vehicle capacity and time windows. Time windows, which restrict when a customer can be serviced, are crucial for modeling realistic scenarios and significantly impact solution feasibility and cost.
Overview