Let's take for example, the Sope Creek Trail. It starts near Sope Creek on Paper Mill Road and runs to the Cochran Shoals Trail along the Chattahoochee. It's a multi-use trail where people including me, hike, run, walk their dogs, and bike. But some cyclist seem to confuse a multi-use trail with a racetrack, bombing down into the valleys at pretty much full speed. Now I understand the attraction of speed, it's fun. But there's a place for it and it's not on a trail with two way traffic and where around the next corner could be a child or an elderly person. The same thing applies to a lesser degree on the Silver Comet Trail, where hammerheads in pacelines swerve around people pushing babies in strollers. It's crazy, it's dangerous, and it's rude. Just as the street isn't the place to see how fast you can go in your car, MUPS are not the place to see how fast you can bike.
I fear if cyclists continue to use MUPS as racetracks someone is going to get hurt, and sadly if history is any indication all cyclists will get the blame.
Now this can't come as a surprise. Cars are expensive. They're expensive to buy, expensive to insure, expensive to maintain, expensive to run, and when times are tough the high cost of cars hits home. Will this happen in the US? Probably not, Italy has an extensive rail network that provides an alternative to driving. The US rail network, is not as extensive or accessible.