How to handle unreachable tasks

This article goes over what unreachable tasks are, when we can see them, and how to address them.

What are unreachable tasks?

Unreachable tasks are pick-up or delivery tasks that are associated with an address that is not accessible via the vehicles available.

When can we see unreachable tasks?

When optimizing tasks, it is possible for the optimizer to finish with tasks that are orphans due to unreachability reasons. 

The message will then display UNREACHABLE CONSTRAINT.

In order to analyze this, the details page of the problematic task displayed in the error message needs to be opened, and its delivery address needs to be looked into on maps.

In most cases, the reason is that the delivery street is not accessible for the type of vehicle assigned to perform the delivery.

How to handle unreachable tasks?

Option 1

In such a situation, the task delivery address can be updated to a nearby point that the vehicle can reach. Additionally, the details regarding the initial delivery address can be provided in the task details for the driver to be aware of.

Option 2

Another option is to use the onfly feature, which overpasses any constraints and forces the task into the round. This feature should be used sporadically and only in situations when other alternatives are not available, as the restrictions that make the task unreachable for the vehicle might present themselves during the delivery: construction works on the road, temporary road closure, etc.

Additional options (less recommended)

It is also sometimes the case that orphan tasks will become reachable by adjusting part of the advanced parameters of the optimising algorithm. These are available under Optimisation > Optimisation > enable Advanced Parameters

Caution!

Any changes in the parameters of the section, however minimal, can have a drastic outcome on the nature of the future rounds. It is therefore recommended to sync with your dedicated CSM prior to any alterations and to first validate with them any adjustment proposals.