They have the same kind of thing in colorado.

http://www.aircarecolorado.com/rapidscreen/

They use onramps and measure the tailpipe emissions. If you pass going through it 3 times, you can get your emissions certification in the mail insted of going to a testing station.

Sorry, diesels can't be tested with it. They also can't fail a car with the rapidscreen tests. I just love covering their "camera" with thick, black soot when I go through them.