GHG Vehicle Test Group means vehicles that have identical
test group,
vehicle make and
model,
transmission class and
driveline,
aspiration method (e.g.
naturally aspirated,
turbo-charged),
camshaft configuration,
valvetrain configuration and inertia
weight class.
Since the 2001 model year, light-duty vehicle engine families are known as "test groups". There are many different test groups; for example, the Ford F-150 could have 10 or more test groups, depending on the engine size, gross vehicle weight, and drivetrain of the vehicle.
See also
References