Yeah, I'm really not sure about this - stories of the strange history of the Eisenhower freeway system are extremely common and there's just a surprising amount of myth around them, like the airplane landing thing that we've seen elsewhere in the thread. It's probably unnecessarily conspiratorial to think that the motivations were anything other than what was officially said (e.g. economic advantages), but I give a certain weight to evacuation as a motive because the vast majority of the efforts made towards survivability were remarkably secretive and it was common, at the time, for the government to use cover stories as justification for survivability efforts. Consider, for example, how FEMA used the FBI as a "front" for the crisis relocation program in order to deny their involvement. It's the kind of secret-keeping that seems really pointless and strange now (how much does it even matter to anyone if it's the FBI or FEMA inventorying relocation sites?), but is an artifact of the ultra-paranoid and minimally accountable atmosphere of the time. Most of these things remain pretty secretive today, not necessarily because there's some ongoing push to keep it a secret, but through the more boring mechanism of once secret, now obscure documents being hard to get declassified.

So I sort of suspect that evacuation was a bigger factor than the government admits, but that's purely speculative. Just like suburbanization there are definitely a lot of reasons the interstates happened.

It’s really common for decisions to be made for more than one reason, even if some of those reasons are just advantages brought up during the planning discussions. I can easily see the defense motives as being one of the many factors involved in the freeway development.

Right, and if my borderline conspiracy theory that evacuation was a bigger factor than we know today is at all true, I'm not saying that the federal DOT is lying to us today or anything. If there was a considerable FEMA influence in the motivation and design of the system, staff today probably just don't know about it. A lot of this stuff happened in face-to-face conversations, a lot of the documentation was classified and by the time it hit the DECL ON it was moldering in a bankers box somewhere... the same reasons that a lot of stuff about the relocation program isn't very well known today despite it being declassified. One of the consequences of secrecy is that the whole thing is more likely to just be forgotten as decades go by and the people who were in the know cycle out. And FEMA and its precursors seemed to have a particularly weird and insular inner culture that makes them hard to talk about from a historical perspective today.

I mean, you can just read the original text. Section 108(a):

>It is hereby declared to be essential to the national interest to provide for the early completion of the "National System of Interstate Highways", as authorized and designated in accordance with section 7 of the Federal-Aid Highway Act of 1944. It is the intent of the Congress that the Interstate System be completed as nearly as practicable over a thirteen-year period and that the entire System in all the States be brought to simultaneous completion. Because of its primary importance to the national defense, the name of such system is hereby changed to the "National System of Interstate and Defense Highways". Such National System of Interstate and Defense Highways is hereinafter in this Act referred to as the "Interstate System".

https://www.govinfo.gov/content/pkg/STATUTE-70/pdf/STATUTE-7...