Comment by rft

A related tidbit of trivia: some highways around the world are intended as emergency airfields. It doesn't mean you can just stop traffic and land, you need to prepare the area, e.g. remove dividers, but it can be done relatively fast if needed.

Wikipedia has some info: https://en.wikipedia.org/wiki/Highway_strip

At least here in Germany many were abandoned/removed, but you can still see traces around. The German Wikipedia on this topic has a list.