The Motorless Highway

State highway M-185 on Mackinaw Island, Michigan, is the only state highway in the US that prohibits motorized vehicles.

The first city ordinances banning all motorized vehicles from the island were passed in 1896, with similar state park rules coming by the 1920s. As such, other than a handful of emergency and utility vehicles as well as others by special, limited-time permit, no cars or trucks are allowed on the island and no motorized vehicles appear on M-185. Traffic on this highway is by foot, on horse or by horse-drawn vehicle, or bicycle.The M-185 designation was first assigned to Lakeshore Drive around Mackinac Island before 1936.