Passenger-Car Equivalent and HVF

f_{H V} = \frac{1}{1 + P _{T} ( E _{T} - 1 ) + P _{R} ( E _{R} - 1 )}

Trucks and RVs count as ET or ER passenger cars. PHF and fHV adjust ideal capacity. ET is larger on grades and for longer trucks. HCM tables give ET vs grade, length, and percent trucks.

$E_{T}$: PCE of a truck
$P_{T}$: Truck proportion (decimal)
$f_{H V}$: Heavy-vehicle factor

Step-by-step solved example

PT=0.10, ET=2.5, no RVs. fHV?

A truck occupies more of the lane than a passenger car (ET).

1. Denom
1+0.10(1.5)=1.15.
2. fHV
fHV=1/1.15=0.870.
$f_{H V} = 0.870$

Answer: 0.870

10 practice questions

0/10 correct

1.If ET=1, fHV=

2.More trucks (larger PT) make fHV

3.Steep upgrades raise

4.Capacity of a freeway lane is about

5.PHF = V / (4 × V15). A PHF of 0.85 means

6.ER is the PCE of

7.Level terrain ET is typically near

8.fHV is dimensionless because

9.PT=0.20, ET=3. fHV=

10.Truck climbing lane is warranted when