PROBLEM $2$

A four$-$lane urban freeway is located on rolling terrain with a free$-$flow speed of $70$ mph$,$

$12-$ft lanes, and no lateral obstructions within $8$ ft of the pavement edges. The traffic

stream consists of cars, buses, and large trucks $($no RVs$).$ A weekday directional peak$-$

hour volume of $1800$ vehicles $($regular users$)$ is observed, with $700$ arriving in the most

congested $15-$min period. Note that both parts a and b require HCS software

verification. Specifically, you are required to show at least $3$ trials in part a$.$

a$)$ If a LOS no worse than C is desired, determine the maximum number of large

trucks and buses that can be accommodated in the peak$-$hour traffic stream.

b$)$ If $180$ of the $1800$ vehicles observed in the peak hour were large trucks and buses,

what would the LOS of a different segment of this freeway be on a $1-$mile, $5\mathrm{.}5\%$

upgrade? Assume PCEs for a Mix of $50\%$ SUTs and $50\%$ TTs $($Use Exhibit $12-$

$27)$ of HCM$6$E$.$