$15-21$

For the data provided in Problem $15-3,$ determine $($a$)$ minimum length of crest vertical curves, $($b$)$ minimum length of sag vertical curves, using the rate of vertical curvature method when joining two segments at maximum grade, $($c$)$ maximum superelevation, and $($d$)$ maximum degree of curve $($use fs$=0\mathrm{.}15($deg$-$min$-$sec$).$