I used to live in a small mountain town. The official vehicles were ancient so any time there was snow I'd see the carriers in Tacomas or Jeeps with a magnetic US Mail decal on the side. They also modified their routes slightly to accommodate left side steering wheels.
Interestingly a mate back in the 90s used to g to the US from Australia and ship back container loads of classic British cars and car parts sourced cheap in the US at a time when that fad was on the wane there and bargains could be had that sold for a good markup in Australia.
Mail delivery trucks have the steering wheel on the right side so that the driver doesn't have to get out in order to reach the mailbox. When using normal cars, they're modifying the routes slightly.
