$3\mathrm{.}47$ A horizontal curve was designed for a four$-$lane

rorizontal

highway for adequate SSD$.$ Lane widths are $12$ ft $,$ and

elevation.

arve is at

$PT$ of the

the superelevation is $0\mathrm{.}06$ and was set assuming

maximum $f_s.$ If the necessary sight distance required $52$

ft of lateral clearance from the roadway centerline, what

design speed was used for the curve?