Highway M-185 is the only highway on Mackinac Island in northern Michigan, a vacation location. Cars have been banned from the island since the 1890s after the first cars introduced on the island spooked the carriage horses and caused accidents. The scenic M-185 has remained almost entirely car-free ever since. Only horses, horse-drawn vehicles and bicycles are allowed here, which makes this highway unique and the only one of a kind. The highway offers beautiful, scenic views.

More Info: en.wikipedia.org