DESIGN PROBLEM $1$

A divided rural multilane highway is required to cope with a given AADT $($see the corresponding assigned unique value received via email$).$ A $70\backslash (\backslash$mathrm$\{$mi$\}/\backslash$mathrm$\{$h$\}\backslash )$ design speed is chosen with lanes of a standard $3\mathrm{.}65$ m width and obstructions within $1\mathrm{.}22$ m on both sides of roadway. The terrain is rolling and the percentages for the various heavy vehicle types are as follows: $\backslash ($ P$\_\{$T$\}=5\backslash \%,$ P$\_\{$B$\}=7\backslash \%\backslash )$ and $\backslash ($ P$\_\{$R$\}=5\backslash \%\backslash ).$ The Driver Population is "Ideal". The Peak Hour Factor $($PHF$)$ is $0\mathrm{.}80$ and the Directional Factor $\backslash ($ D $\backslash )$ is estimated at $0\mathrm{.}55.$

The client is required to design based on high performance and sustainability requirements. In detail, the highway is required to maintain LOS B and it is to be designed to cope with the $\backslash (30^\{\backslash$text $\{$th $\}\}\backslash )$ highest hourly volume during the year.

Provide step$-$by$-$step calculations and critically motivate the followings:

$1\mathrm{.}1.$ The number of lanes in each direction.

$1\mathrm{.}2.$ If the client requires a reduction of $1$ lane per direction, demonstrate what is the best solution to adopt between a$)$ extending the "Distance to obstruction from travelled edge" up to $1\mathrm{.}83$ m or greater, or b$)$ rearranging the whole highway over a type of terrain from "rolling" to "level". Critically discuss and justify the obtained results and indicate which option is more sustainable and why.

$1\mathrm{.}3.$ To support sustainability of the project, discuss potential solution$($s$)($also in combination$)$ other than those at point $1\mathrm{.}2,$ that may reduce number of lanes for the concerning highway. Based on the competent Highway Authority, the following parameters cannot be varied: divided multi$-$lane arrangement; AADT; Design Speed $\backslash (=70\backslash )\backslash (\backslash$mathrm$\{$mi$\}/\backslash$mathrm$\{$h$\}\backslash )$; "ideal" driver population; $\backslash (\backslash$mathrm$\{$PHF$\}=0\mathrm{.}80$ ; D$=0\mathrm{.}55\backslash ).$

Provide step$-$by$-$step calculations to prove your point and rank the found solutions from the most to the less sustainable, including providing critical comments to justify your answer.

Note: the unique parameter provided separately via email for the design problem $1$ is AADT.

DESIGN PROBLEM

Parameter Value

$1-$ AADT $[$veh$/$day$]-35825$

If needed

$2-$ Bearing $1[]24$

$3-$ Bearing $2[]54$

C $[$ m$/$s$3]0\mathrm{.}53$

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