In many logistics operations, efficiency is not just about the number of stops but about the distinct locations visited. To optimize routes effectively, you may want to limit the number of unique pickup or drop-off clusters a vehicle visits in a sequence, rather than just the total number of stops.
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 the context of the Stateless API, Vehicle Efficiency refers to a set of constraints designed to optimize and control how a vehicle's capacity is utilized throughout its route. These constraints allow you to enforce rules about minimum loads during a trip and maximum loads at the end of a trip.
A node's servicetime says how long the stop takes. Sometimes that depends on the vehicle as well as the stop: a large truck needs longer to park and open up than a van, and a vehicle without a tail lift is slower to unload. **Vehicle service time** adds a vehicle-dependent amount on top of each node's own servicetime whenever that vehicle serves the node.