$($a$)$ A four$-$legged intersection has two lanes in each direction and a two$-$phase cycle. One

phase of the intersection has two lanes, one for left$-$turns and straight$-$through traffic and

the other lane for right$-$turns and straight$-$through traffic. The design flow rates and

saturation flow rates are found below. Calculate the critical flow ratio for this phase and

determine which lane is the critical lane.

$($b$)$ An intersection approach has $3$ lanes, permitted left turns, $18\%$ left turns with a through

vehicle equivalent of $7\mathrm{.}25,$ and a saturation flow rate of $2150yphgpl($vehicle per hour of

green per lanc$)$ for through vehicles under prevailing conditions. What is the left turn

adjustment factor for the intersection?

$($c$)$ For the intersection in part $($b$),$ determine the saturation flow rate and saturation headway

for the appronch, including impact of left$-$turning vehicles.

$($d$)$ For the intersection in part $($b$),$ if the effective green time is $50$ seconds in a cycle with a

length of $80$ seconds, what is the capacity of the approach in vehicles per hour?

$($e$)$ A two$-$phase cycle has the same saturation flow rate for each phase and a total available

green time of $80$ scconds. Calculate the available green time for each of the two phases

using the data in the following table.