Say you have two trucks doing a cross country run(on the I-10 to keep things easy) and a return run. One with an automated system that can drive while the driver sleeps and one without.

Truck A: Can drive 24 hours a day and can cover the distance there and back in about 3 days

Truck B: Can drive 11 hours a day and can cover the distance in ~7 days.

The first Driver can do the trip twice in the same amount of time. Halving the number of drivers required for that route or freeing up drivers on that route for other jobs.