A horizontal curve with $70-$degree central angle is to be designed for

a $4-$lane road $(2$ lanes on the east bound and $2$ lanes on the west

bound$).$ The lane width is $12ft.$ The curve's superelevation is $10\%.$

The posted speed limit is $55mph$ The coefficient of side friction is

$0\mathrm{.}12.$ The road is flat $($zero longitudinal grade$)$ on that section of the

road. Calculate the following $[7$ Points Total$]$:

A$-$ Radius measured from the inner lane $(R_v)[2$ Points$]$

hint: use the formula $R_v=\frac{V^2}{g(f_s+e)}$

B$-$ The radius measured from the center of the road $($R$)[2$ Points$]$

C$-$ Degree of curvature $[1$ Point$]$

D$-$ Length of the curve $[1$ Point$]$

E$-$ Middle Ordinate distance needed to provide adequate stopping

distance $(M_s)[1$ Point$]$