What is the minimum radius, Rmin, that can be used on a horizontal curve with a 70 mph design speed, a maximum superelevation, emax = 8%, and a side friction factor, f = 0.10?
Answer:
0.01e + f = V2/15R
Rmin = V2mph / 15 (0.01e + f) = 702 / 15 (0.01*8+0.10) = 1814.80 ft