[gresrun]

It was also built to allow the U.S. Army to rapidly move convoys of trucks, tanks, & materiel around the U.S.[0].

[0]: https://en.wikipedia.org/wiki/Federal-Aid_Highway_Act_of_195...

[dimitrios1]

And also built to allow rapid evacuation of large cities in case of nuclear attack. I think it's lost on a lot of people today just how many things we did in the 50s, 60s, and 70s because we were scared of being bombed.