Problem $1$

If the design speed is $45$ mph$,$ determine the minimum length of the sag curve shown below, without using the rate of curvature, K to determine the curve length, taking in to consideration the sight stopping distance, comfort and appearance of the roadway.

$-5\%$

$-2\%$

EVC

Hint:

use S$($R$)=1\mathrm{.}47$ut $+($u $^2)/(30($a$/$a plus$/$minus G$))$

Assume t $=2\mathrm{.}5$ sec$.$; a $=11\mathrm{.}2$ft $/($s $^2)$ g $=32\mathrm{.}2$ft $/($s $^2)$ G is the grades in $\%($in this case use $0\mathrm{.}05$ and the sign before it will be negative$).$ You will then check for the follwing three $(3)$ criteria to determine the length of curve: Sight distance, Appearance and Comfort $($check notes$).$ NB$.$ The minimum curve length is the maximum length computed from the $3$ criteria.