Question $4.(1\mathrm{.}25$ point$)$

Given: A tangent of N $26$ deg ${18}^{\text{'}}W$ meets a tangent of S $83$ deg $39\text{'}$ E at station

$17+41\mathrm{.}34.$ The design speed is $80k\frac{m}{h},e_{\text{m}\text{a}\text{x}}$ is $0\mathrm{.}10,$ the normal crown is $2\%,$ and

the highway has two lanes. A bridge is supposed to begin $399\mathrm{.}90$ m downstream

of the PI along the SE bearing.

Find: For a simple circular curve, determine whether the bridge will need to be

superelevated or can be on the tangent at all, using $R_{\text{m}\text{i}\text{n}}$ and the tabulated Lr$.$

$(0\mathrm{.}75$ point$).$ Also determine the station of the end of the back tangent runout.

$(0\mathrm{.}5$ poin$)$