Fleet
What one transport cost the load that asked for it.
The three durations partition the wait: waitForAssignment runs from posting until a vehicle committed, waitForArrival from there until the load was aboard, and timeAboard from there until it was set down. Their sum is totalTime.
The third is named for the interval rather than for the journey, matching FleetSystem.timeAboard and for the same reason: the passive subsystem's transportTime means request to set-down, which is the whole of totalTime here rather than this last leg of it.
Parameters
posting to delivery
posting until a vehicle committed to the task
the commitment until the load was aboard
aboard until set down, including any unloading delay
how much of the above the vehicle spent unable to claim the space ahead of it
how much of the above the vehicle spent out of service -- broken down, waiting for a technician, or being pushed out of the way. Part of the intervals above rather than outside them: the load was waiting, or aboard, throughout. Zero for a fleet that cannot fail.
how far the vehicle travelled while carrying the load
which vehicle carried it
how many times the task was taken back and given to someone else. No counterpart in the passive subsystem's result: it is the observable trace of re-tasking, and is zero unless a policy revokes.