Question

A Class III two-lane highway in rolling terrain, during the peak hour, has a flow rate of 528 veh/h in the analysis direction and a peak-hour factor of 0.88. The traffic stream consists of 6% trucks, 3% buses, and 5% recreational vehicles. Determine the analysis flow rate.

Answer 1

661 veh/h

Step-by-step explanation:

All the values are taken from transportation research board, Highway Capacity Manual 2010 Tables

Hourly volume of vehicles in analysis direction = Vd = 538 veh/h

Peal Hour Factor = PHF = 0.88

Determining Grade adjustment factor (Fg) and Heavy vehicle adjustment factor (Fhv)

Vd/PHF = 528/0.88 = 600

Select values for ATS for polling terrain

Fg = 0.97

Et = Passenger car Equivalents for heavy vehicles (PCE) for rolling terrain

= 1.7 (for 600)

Er = PCE for Recreational Vehicles

= 1.1 (for all flows)

Fhv = 1 / (1 + Pt( Et - 1 ) + Pr (Er -1))

Where,

Pt = Proportion of trucks and buses in the traffic stream

Pr = Proportion of recreational Vehicles in traffice stream

Pt = 6 + 3 = 9% = 0.09

Pr = 5% = 0.05

Fhv = 1 / (1 + 0.09(1.7 - 1) + 0.05 (1.1 - 1))

= 0.936

Analysis flow rate

Vd = (Vd/PHF)/(Fg * Fhv)

= 600/(0.97 * 0.936)

= 660.85

≅ 661 veh/h