Were U.S. Interstates Really Designed as Runways?

The idea that U.S. highways were designed to work as emergency runways is nothing more than urban legend. No one seems to know exactly when the rumor began, but it can be traced to legislation that dates back to the 1940s. At first glance, the idea seems like both common sense and a total head-scratcher. Of course, a military plane should be able to land on a nice, wide road in an emergency, but then what about all the roads that are too curvy or too hilly or have an otherwise unsuitable landing surface? What about the cars and trucks that are probably already on the highway, with no way of being warned of this emergency? Those who started the rumor accounted for those questions. For example, the whole road wasn’t supposed to be used as a runway, just 1 out of every 5 miles. This ratio is supposedly to account for turns, elevation changes, and densely-populated areas. So, what’s the plan if there’s ever an emergency that requires airborne planes that are unable to reach their destinations to land immediately? Small municipal and private airports are the most obvious solution, while military bases are another option. There are actually little-used and little-known runways all over the place that are a logical location for an emergency plane landing in a war or terrorist situation, and that was seen during the mandatory order for all aircraft to land during the 9/11 terrorist attack. None of those aircraft, however, landed on an interstate highway.