One important thing to consider when planning routes is having the right vehicle availability. Although it's easy to set vehicle availability to the same time as the customer's time window, it's not that practical.
Fact is that the route optimisation need to fit in the following factors, not just delivery time, within the vehicle availability time window:
Loading time - The time it takes to load a vehicle before the route starts
Driving time - The time it take for a driver to driver to the first stop, between stops, and from the last stop back to the depot.
Service time - The time if takes for a driver to complete a delivery
Breaks - Time for breaks that have been assigned when planning
Having an optimised and accurate vehicle availability is a key factor. We have listed a few examples below to highlight how different availability can have huge impact on the efficiency.
Note: Just because the vehicle is available from a certain time doesn’t mean the loading has to start at the beginning of the availability.
Example 1
Vehicle availability: 14:00-20:00
Delivery time window: 14:00-20:00
Vehicle availability is the same as the customer’s time window. This means that the vehicle can’t start the loading process before 14:00. On top of that, you also need to factor in the driving distance to the first stop, which means that the first delivery in this case is performed at 14:45.
The driver then continues to deliver before heading back to the depot at 19:30 in order to return before 20:00. These means that the driver is losing out on 75 minutes of potential delivery time (i.e. customer’s time window), which has a big impact on the overall efficiency.
Potential delivery time: 14:45-19:30 (4 hours, 45 minutes)
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Example 2
Vehicle availability: 13:00-20:30
Delivery time window: 14:00-20:00
In this example, we’re adding 60 minutes extra availability before and 30 minutes after the customer’s time window. The vehicle starts the loading process at 13:00 and can use 30 minutes driving time before performing the first delivery at exactly 14:00.
The driver the continues to deliver before heading back to the depot at 20:00, after the customer’s time window is closed, and returns at 20:30. As you can see, we’ve expanded the potential delivery time to cover the entire customer time window. The driver has more time and can (if vehicle capacity allows for it) fit more deliveries in on the same route.
Potential delivery time: 14:00-20:00 (6 hours)