I don't think they were. I've got kind of a side project I work on from time to time involving what it would take to provide an 'adequate' road system for sprawl development, even at low densities. I get something like a 1 mile grid of four and six-lane arterials. Areas of Florida with aggressive impact fee systems have this. And it's still not enough.
Macon really wants to go that route, either.
My point is we need to devote great effort to coming up with a better plan. At one point during Atlanta's attempt to draft an RTP, the Regional Business Coalition issued a statement calling for, among other things, 'business- quality information' for use in planning. The thing to remember is that business- quality information will eventually appear. It will come from business. The trick is to know in advance what the results of public decisions will be, so that as business acts in its own interests, it will also be acting in ours.