How do states use OBD II for emission inspections?

Many states connect a computer directly to a vehicle's OBD II system. The inspector can then read "faults." In some states, this type of inspection has replaced the tailpipe emission test.
See also:
Volvo's recommendations
Why does Volvo believe that no child should sit in the front seat of a car? It's
quite simple really. A front airbag is a very powerful device designed, by law,
to help protect an adult.
Beca ...
Gasoline containing alcohol and ethers, "Oxygenated fuels"
Some fuel suppliers sell gasoline containing
"oxygenates" which are usually alcohols or
ethers. In some areas, state or local laws
require that the service pump be marked indicating
...
Auto-brake
If a collision is imminent and the driver has not
applied the brakes or begun to steer around the
vehicle or pedestrian, the auto-brake function
is activated without the driver pressing the
br ...
