Question

A six- lane freeway ( three lanes in each direction) in a scenic area has a measured free- flow speed of 55 mi/ h. The peak- hour factor is 0.80, and there are 8% large trucks and buses and 6% recreational vehicles in the traffic stream. One upgrade is 5% and 0.5 mi long. An analyst has determined that the freeway is operating at capacity on this upgrade during the peak hour. If the peak- hour traffic volume is 3900 vehicles, what value for the driver population factor was used?

Answer 1

0.867

Step-by-step explanation:

The driver population factor (
`f_(p)`)can be estimated using the equation below:

`f_(p) = (V)/(PHF*N*f_(HV)*v_(p))`

The value of the heavy vehicle factor (
`f_(HV)`) is determined below:

The values of the
`E_(T)` = 2 and
`E_(R)` = 3 are gotten from the tables for the RVs, trucks and buses upgrades for passenger-car equivalents. Therefore:

`f_(HV)` = 1/[1+0.08(2-1)+0.06(3-1)] = 1/[1+0.08+0.12] = 1/1.2 = 0.833

Furthermore, the vp is taken as 2250 pc/(h*In) from the table of LOS criteria for lane freeway using the 15 minutes flow rate. Therefore:

`f_(p)` = 3900/[0.8*3*0.833*2250] = 3900/4498.2 = 0.867