Driving the posted 40 miles-per-hour speed limit on Western Colorado's Riverside Parkway is absolutely impossible. One can drive it at 45. It's even easier to do 50. To be completely honest, it's can even be done at 35. Put simply, 40MPH is a speed cars were never meant to do. Here are five things drastically easier to do than driving 40MPH on the Riverside Parkway.