Hi
Read your initial post and did some research. Turns out Colorado testing stations will not validate whether you
must have a test or not - they just test and collect the revenue.
Further investigation revealed that Diesel vehicles are not subject to standardized emission testing in Colorado. They must
have a "opacity test" - they put a monitor on your exhaust pipe and test. If your RV is like mine, the diesel
exhaust is virtually transparent.
I didn't dig deep enough to find out the fee for this type of testing, but have to believe it is less expensive than
a full blown emission test.
Here in Nevada, we get a waiver for Diesel RV's so never have to face the testing routine.
You might want to check into this whole thing deeper. Good Luck
John