I’ve thought that if any outfit would benefit from EVs it would be the Post Office. Relatively low daily mileage that ends right back where they start.
I saw a test vehicle on a mounted USPS route a few years ago. No wasteful idling like the gas trucks. Current EVs have regenerative braking which recovers energy and spares brake wear. Far fewer parts to maintain. I have friends with Teslas, their idea of routine maintenance is filling the windshield washer fluid.
I used to work with a man whose father was a milkman in Australia. He used a mule drawn wagon until the 1990s. The mule was trained to walk slowly while the deliveries were made. It would avoid obstacles like a parked automobile and allowed him to do the job with one man and one mule. When he had to change to a truck his cost went up and using the truck with a driver actually took more time.
As slow as mail carriers go down the street an animal drawn vehicle might be more efficient.