A good read on this topic is "The Big Roads" by Earl Swift. It has been a couple of years since I read it so the details are a little hazy.
As a friend of mine remarked, "at the end of the 30s what we think of as Interstates (not just the main trunks but especially the interchanges, circumferential belts, cloverleaves and what have you) were still blackboard theory. That's why it was in the 1939 World's Fair Futurama exhibit instead of actual testing..."
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Actually, by the early 30's most of the basic ideas you mentioned had been developed or discussed. They had laid out most of the routes, developed the numbering system, etc. The biggest issue was how to fund the roads which took until after the war to resolve.
I was dead set against toll roads until about 10 years ago but now I see there is a need for them. With politicians too dang scared to raise the fuel tax rate, roads everywhere are getting worse and worse. If the tolls are actually used to maintain the roads, I don't have much of a problem but too often they are used a money maker for other efforts in a state. From what I remember the toll roads in Kansas and Oklahoma were well maintained; the New York Thruway system is okay, not great, not terrible; the toll road in Delaware is a total rip-off, roads are bad, always torn up, and the rates are high.