The freeway bears several names in addition to the I-75 designation. The southern segment was called the Detroit–Toledo Expressway during planning in the 1950s and 1960s. Through Detroit, I-75 is the Fisher Freeway or the Walter P. Chrysler Freeway, named for pioneers in the auto industry. Sections on either side of the Mackinac Bridge are the G. Mennen Williams Freeway or the Prentiss M. Brown Freeway, named for politicians who helped get the bridge built. Officially, the entire length is the American Legion Memorial Highway, after the organization of the same name. Various sections carry components of the four Great Lakes Circle Tours in the state.