[Timber Rattler]

Ike was actually inspired by Japanese Emperor Taishō---after World War I, while planning for a theoretical defense against a Japanese invasion, the future Allied Supreme Commander tried to lead an Army convoy from Washington, DC to the West Coast to see how long it would take to respond if Imperial troops ever landed in California.

Ike didn't get very far. The convoy got stuck in the mud in Emmitsburg, Maryland, and from that day forward, Ike began thinking about building better highways to connect east and west coasts for defense purposes.

So, it's the Japanese's fault.

[Lonesome in Massachussets]

I think both experiences formed Ike’s outlook. The U.S. Army was very grateful for the autobahn (and the Ludendorff Brücke, which was expressly built for the defense of the Reich).