This stamp shows one of the first official gasoline-powered vehicle used by the United States Post Office Department for the collection of mail from street letterboxes. The stamp is one of four 25-cent Classic Mail Transportation commemorative stamps issued November 19, 1989. All four stamps were shown on a previous post on maximum cards issued by the USPS here.
This Maximum card is ©1989 The Maximum Card Collection, A Division of Unicover Corporation. Another early postal vehicle, a mail wagon of the 1920s, is shown on the maximum card.
This is a post for Sunday Stamps at Viridian's Postcard Blog