49. The Oklahoma River Trail
Location: Oklahoma City, Okla.
Distance: 13 miles
Best Suited For: All bike types
The best thing about the Oklahoma River Trail's 13 miles of flat, paved, riding surface is that it's free of traffic crossings. Yeah, you heard that right. So feel free to put on your time trial helmet, strap on your aero bars, and practice time-trialing to your heart's content, even if it means mowing down every roller-blader and stroller in your way.