Manual Calculation: Apply the Highway Capacity Methodology and calculate the free flow speed, density and level of service for a rural freeway with the following characteristics:

1650 veh/hr per direction
2-lanes per direction
0.75 interchange / mile
Rolling terrain
12-foot lanes
Obstructions at 2 ft from median lane, 4 ft from outside lane
10% trucks, 6% RVs
PHF = .91
Non-commuter drivers (fp = 0.9)

A four-lane urban freeway (two lanes in each direction) is located on rolling terrain and has 12-ft lanes, no lateral obstructions within 6 ft of the pavement edges, and an interchange every 2 miles.

The traffic stream consists of cars, buses, and large trucks (no recreational vehicles). A weekday directional peak-hour volume of 1800 vehicles (familiar users) is observed, with 700 arriving in the most congested 15-min period.

If a level of service no worse than C is desired, determine the maximum number of large trucks and buses that can be present in the peak-hour traffic stream.