A six-lane divided multilane highway (three lanes in each direction) has a measured free-flow speed of 50 mi/h. It is on mountainous terrain with a traffic stream consisting of 7% large trucks and buses and 3% recreational vehicles. The driver population adjustment in 0.92. One direction of the highway currently operates at maximum LOS C conditions and it is known that the highway has PHF=0.90.
How many vehicles can be added to this highway before capacity is reached, assuming the proportion of vehicle types remain the same but the peak-hour factor increases to 0.95?
Process: (1) determine passenger car equivalent for trucks and buses; (2) determine passenger car equivalent for recreational vehicles; (3) calculate heavy vehicle factor; (4) determine 15-min passenger equivalent flow rate for current conditions; (5) determine 15-min passenger equivalent flow rate at full capacity; (6) calculate the volume for current and capacity conditions; (7) take the difference of the two volumes to determine how many vehicles were added