$($Points: $15)$ A horizontal curve was designed for a two$-$lane highway with $11-$foot lanes and $3-$foot shoulders. The curve has the following conditions:

$R=700$ feet

Posted speed limit $=40mph$

Is it safe for drivers if a large billboard is placed $5$ feet from the edge of the shoulder? Assume perception and reaction time is $2\mathrm{.}5$ second and $a=11\mathrm{.}2f\frac{t}{sec2}$