Interstate 475 forms an urban loop joining I-75 with Downtown Flint from the west. The freeway carries four lanes north to Exit 4 (Bristol Road), six lanes north to Exit 13 (Saginaw Street) and four lanes along the rural stretch west back to I-75. A four-level interchange joins the below grade freeway with Interstate 69 amid ramps to Downtown.
The Michigan State Highway Department Recommenced Interstate Route Numbering in 1958 numbered the urban route for Interstate 75 at Flint as I-175. The State revised the numbering of loops and spurs to conform with the American Association of State Highway Officials (AASHO) recommendations of assigning odd number prefixes for spurs and even number prefixes for loops. Subsequent correspondence on August 15, 1958 reassigned the loop at Flint as Interstate 475, which AASHO concurred with on August 29, 1958.
Interstate 475 was designated as a 17.5 mile long freeway through Flint in 1970.1 The second level of the stack interchange with Interstate 69 opened as part of the M-21 and M-78 freeway completed from Saginaw Street to Center Road on December 21, 1971.2 Opening of the first two sections of the I-475 mainline occurred by 1973. The southern portion ran north 6.4 miles from I-75 to the M-21 freeway near Downtown Flint. The northern 3.4 mile long segment connected I-75 east with Saginaw Street (Exit 13).3 The remaining section of I-475 was finished in 1981.1