$6\mathrm{.}1$ A six$-$lane freeway $($three lanes in each direction$)$

has regular weekday users and currently operates at

maximum LOS C conditions. The lanes are $11ft$ wide,

the right$-$side shoulder is $4ft$ wide, and there are two

ramps within three miles upstream of the segment

midpoint and one ramp within three miles downstream

of the segment midpoint. The highway is on rolling

terrain with $10\%$ large trucks and buses $($no

recreational vehicles$),$ and the peak$-$hour factor is $0\mathrm{.}90.$

Determine the hourly volume for these conditions.

$6\mathrm{.}2$ Consider the freeway in Problem $6\mathrm{.}1.$ At one point

along this freeway there is a $4\%$ upgrade with a

directional hourly traffic volume of $5435$ vehicles. If

all other conditions are as described in Problem $6\mathrm{.}1,$

how long can this grade be without the freeway LOS

dropping to $F?$