Makes sense... the longest route in the US is less than 200 miles long, and it probably isn't even relevant since it's one of the rural routes driven by a carrier using their own vehicle.

If anything was tailor-made for EVs, it's the short-to-medium range stop-and-go of a delivery route. No idle losses, regenerative braking between the many stops, predictable distance, daily return to a central location where charging can be handled.

Edit: A little more googling says that the average route is only 24 miles, and that nearly all of them are less than 70 miles. We should have gone electric for the average postal route 30 years ago... even boring old lead-acid batteries could have managed that!