$(15$ Points$)$ A simple circular curve exists with a degree of curve $D=12$ and e $=0\mathrm{.}08f\frac{t}{f}t$

A structure is proposed on land on the inside of curve. Assume the road is on level grade.

Determine:

$($a$)$ The radius of the curve

$($b$)$ The current maximum safe speed of the curve

$($c$)$ The minimum distance allowable between the proposed structure and the centerline of the

curve such that the current maximum safe speed of the curve would not need to be reduced