Basically, the same path as Route 66 is on the interstate system: I-15 north from LA, transfer to I-40 east at Barstow, then take that to Oklahoma City, where you switch to I-44 north to St. Louis, then finally I-55 to Chicago. That's roughly the same path as Route 66.
Well, for one thing, they couldn't have followed it exactly. Running a 65+ mph highway down the path of a road which in some cases passes down the main streets of towns with speed limits in the 30s--heck, I've heard there's part of the remaining road that are right next to schools, so they're 25 mph school zones during daylight hours. You can't run a 6-lane modern highway down a right-of-way like that, so you're going to end up bypassing a lot of the same towns even with this "I-66." It's necesary to make it an interstate, but you'll lose a lot of the feel as soon as you make that inevitable compromise. At that point, the difference between having a unified "I-66" name applied to the sections of the four otherwise identical roadways is kind of trivial. "I-66" wouldn't be the same as Route 66.But that's what I'm getting at. Why didn't they just take Route 66 and make it into I-66 instead of building Interstates that mirrored it?
Well, for one thing, they couldn't have followed it exactly. Running a 65+ mph highway down the path of a road which in some cases passes down the main streets of towns with speed limits in the 30s--heck, I've heard there's part of the remaining road that are right next to schools, so they're 25 mph school zones during daylight hours. You can't run a 6-lane modern highway down a right-of-way like that, so you're going to end up bypassing a lot of the same towns even with this "I-66." It's necesary to make it an interstate, but you'll lose a lot of the feel as soon as you make that inevitable compromise. At that point, the difference between having a unified "I-66" name applied to the sections of the four otherwise identical roadways is kind of trivial. "I-66" wouldn't be the same as Route 66.
Zoomar, I think you have a point--a lot of the cultural legacy of Route 66 lives on specifically because it was bypassed, left as a living reminder of the era because what it was and exactly how it interacted with the towns and landscapes was incompatible with the interstates. Try to make it a part of that, and I think you'd do more damage to Route 66 than it's taken in its "preserved by omission" state.