Every time I have to go there and sit in their gridlock traffic I thank the gods I moved South

Last summer I had a battle with these nimrods at the Golden location. They insisted my fwd Audi A3 was was all wheel drive and I was in the wrong lane. They directed me to get in a different lane (and in the back) after spending 30 minutes in the "right" lane.
"All Audis are quattros," the dipstick, rotound, manager wantabe, woman pronounced.
They spent 5 minutes looking for the rear driveline after I refused to move to other lane.
YMMV
OTOH, I have vintage plates on my SC and I did not know you could be sent to an emission station if you fail a roadside test. Yikes!

Traffic?! Having lived in NY, DC, and Boston for much of my life, I have yet to see this "traffic" you talk about? ;)

Bill, make sure you know where those vans are located before you go out in your vintage-plated car. If you fail the drive-by test, your car has to go back to being tested annually or bi-annually for the rest of its life.

Here's where you check the location of the MOBILE RAPID SCREEN LOCATIONS.

By the way, that's the reason that I created my dual Cat system. I knew that starting in 2012, those mobile rapid screen vans were going to test for failures, not just passes for registration. Hank Padilla of Hanksville Hot Rods knew about the change too, so we designed a system with the largest/most effective Cats I could fit between SSIs and a custom muffler.

lol, well of course. Traffic for us "western" folk I suppose.

I had a horrible time getting my 1991 past emissions last year. My car had the full B&B exhaust system with heater boxes, but I couldn't even come close to getting it passed.

Ended up installing a new exhaust by B&B with a "sport" cat and a new O2 sensor and passed without an issue. Of course it took B&B about 4 months to build the system so I basically missed all of the last summer driving it (April-September).

I hope they kill it too.....

Bill

Oh the stories I could tell regarding the Golden station. One day you have to use every trick in the book to get a stock Jeep Cherokee to pass only to have a non-catted Toyota Celica Alltrac pass easy. And they don't test diesels so all our trucks had to go somewhere else.

What happens if you go by these mobile screens with key on engine off? Guessing a letter stating to report to a testing center.

The Rapid Mobile Screening system measures your acceleration and speed, as well as an emissions analyzer, and will know if you don't have the engine on. Read more HERE.

As to what happens...I don't know, but you won't fool the system into thinking you have an electric car by shutting it off. ;)

Taking bets on when we will see smog drones.