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Configure Reassignment of Tasks

Tasks can be reassigned between vehicles before the pickup step has been completed. This is beneficial for fleet efficency, since the the best vehicle for a task might change as the state of the fleet changes. For exmaple, due to an unrelated task, a vehicle would be driving by the pick-up location and drop-off location of a task and could complete the task on the way to another task. This guide explains some fundermental trade-offs you can make here as an operator, to balance customer experience and fleet efficiency to your needs.

Reassignment configurations

You can turn off vehicle reassignment, or configure its specific behavior at the fleet level. Currently, there are three configuration options for reassignment:

Vehicle reassignments can occur whenever Fleet Planner is re-optimized. See the FAQ on re-optimization triggers for a list of events that trigger re-optimization.

Time Windows

Partners can configure a time window that is considered when calculating the optimal fleet plan.

The time window consists of a lower and an upper bound (in minutes) and that controls the ETA range that is considered for vehicle assignments.

Time windows are usually configured on a per-fleet scope. Time windows can also be set while requesting a task which overrides the fleet level setting.

Wait Cost

Waiting time of passengers prior to pick up is one metric that Fleet Planner is trying to minimize when suggesting vehicle assignments.

Let us consider the following wait cost function for a time window of (10, 30] in the following plot. The specific values are examples and chosen for illustration purposes only.

Key points for the wait cost function with time window (10, 30]:

Example Scenario

Consider the following initial situation, and how the different configuration options affect the individual rider experience and overall wait cost.

Step 1: Initial situation

Step 2a: Vehicle reassignment OFF

Step 2b: Vehicle reassignment ON

Which configuration option to choose?

The configuration option for vehicle reassignments can be set when a fleet is created or updated. When creating a fleet using CreateFleet, you can adjust the optimizationSettings parameter and when updating a fleet using UpdateFleet you can adjust the updatedOptimizationSettings parameter.

In general, we recommend to turn vehicle reassignment on, as this improves overall fleet efficiency and average wait time for riders to pick up, leading to a better rider experience. You can do so by setting enableVehicleReassignment to true inside the optimization settings.

One undesired side effect vehicle reassignments can have, however, is that a rider that is promised a certain ETA will be assigned a new vehicle for pick up, resulting in a worse ETA. Note that this will only happen if the overall wait cost is lower, so the reassignment likely benefits multiple other riders in terms of way lower ETAs. To prevent this from happening, set disallowReassignmentWhenWaitTimeIncreases to true for the vehicleReassignmentConfiguration object inside the optimization settings.

You can also turn vehicle reassignment off entirely if you are ok with the overall worse fleet efficiency. Leave out the enableVehicleReassignment parameter or set it to false to do so.