Vehicle registration plates of Iowa
The U.S. state of Iowa first required its residents to register their motor vehicles in 1904. Registrants provided their own license plates for display until 1911, when the state began to issue plates. Plates are currently issued by the Iowa Department of Transportation through its Motor Vehicle Division. Front and rear plates are required for most classes of vehicles, while only rear plates are required for motorcycles, trailers and the 1945 base plate. Passenger baseplates. 1911 to 1971. In 1956, the United States, Canada, and Mexico came to an agreement with the American Association of  Motor Vehicle Administrators, the Automobile Manufacturers Association and the National Safety Council that standardized the size for license plates for vehicles (except those for motorcycles) at in height by in width, with standardized mounting holes. The 1955 (dated 1956) issue was the first Iowa license plate that complied with these standards. Current non-passenger and optional plates. Optional plates. Iowa offers its motorists a number of optional issue designs that are available upon the payment of an additional fee. Plates of all types other than the university types are available for both automobiles and motorcycles, the latter using a smaller  overall plate size. University Plates are the only plates not colored the same as the standard issue plate, the color scheme is a yellow base, with the university's main sports team color on both the numbers, and a header denoting the school (i.e. red for Iowa State University, black for University of Iowa, purple for UNI, et cetera).