We can always tell the mail truck from any other vehicle on the street just by sound. Vroom, sigh, vroom, sigh. But someday we may have to go check to see if the mail is in. The Postal Service is experimenting with quiet electric vehicles in Fresno. It’s a great application since they are never far from their charging station and the electric motor probably is more forgiving of all that idling. It should save money in the long run too.