A simple highway curve is planned to connect two horizontal tangents that intersect at sta. 2500 + 00.0 at an external angle of 52 degrees. For a design speed of 60mi/h and a curve radius of about 1.25 times the minimum allowable, calculate:
(a)design rate of superelevation
(b)the required length of superelevation runoff.
Assume a four-lane undivided highway and 10-ft lanes, emax=0.10 and fsmax=0.20. (Note that the limiting value of fs from Table 3.5 is usually smaller, but use fsmax.)