As in, you are forbidden to drive a car on it, but you can bike, walk, or ride a horse on it. The former Wissahickon Turnpike, the main drag through Wissahickon Valley Park in Philadelphia, was built in the 1820s and got its current name in the 1920s when it was closed to vehicles.
On a pleasantly cool weekend morning there were a lot of people in the park, meaning we had to drive around a bit before finding a parking spot. The gravel path is wide and the people spread out so it was a leisurely 8 mile ride.
