I also would say that people in other countires, especially in Europe and Japan, need to be made aware of how great all the old auto trail and US highway routes are. You really see nothing on the interstates if you are a tourist. They are very efficient for speedy travel of course, but definitely not for seeing America or meeting Americans. The old auto trails and the later US highways went right through Main street of all the towns and cities. If the road is the destination, the Interstates are definitely not the way to go. On one Route 66 trip I met some folks from a T-bird group "going down 66." However, almost every time I saw them, they were passing by on the interstate on the way to the next town, while I cruised down the real 66. I can understand not taking your car down La Bajada Hill, but at least go down the old cement highway for gosh sakes.
I would encourage every road geek, Chamber of Commerce, visitor bureau, and civic and business organization to form historic route associations in their town or county. That's how they were started in the beginning to promote travel through small towns, and it can be done again. We don't even have to do all the road building!