Very interesting topic. I am a retired Police / DOT Enforcement Officer from 1986-2011. Weighmaster, Haz-Mat and Cargo tank inspector. Class A CDL holder and driver / trainer. And recently... A Penndot certified 3rd Party CDL Driver/Examiner. The weeklong driver/examiner class focused on trucks and buses , not RV's. It is actually based strictly on Commercial Vehicles by Federal Regs , not state regs. The requirement for a non-com CDL is a state by state thing , not a Federal requirement. This is why the confusion at the DMV test sites. We don't get trained on doing RV's so you will see ( as evidenced on this forum) that different testing locations do it ....differently. As a former officer, the non-commercial CDL has been around a long time but FEW officers know it exists so enforcement is sparse. But having said that, there are some that do know and I agree that if you drive the equivalent size/weight of a commercial vehicle that you should have a license for it. Especially for an air brake vehicle. ( FYI , air brakes alone do not propel any vehicle into CDL territory) Where I do my testing, we are a closed site so I will never test an RV or a bus. We only test our own employees in company vehicles. If I had to test an RV with air brakes, I would treat it like a CMV in every other respect. Pre-Trip, air brake test, backing and finally the road test. The test is virtually identical in every respect to a regular CDL but you cannot ever use a non-com CDL to drive an actual commercial vehicle. If you run any kind of business from your RV (traveling to car shows to sell Model A parts), you are in fact a real CMV and will need DOT authority, medical card, full CDL, logbooks and apportioned plates etc. And remember, a CMV is any vehicle used in commerce over 10,000 lbs registered weight that crosses a state line and if within the state ( PA), anything over 17,000 lbs. So a 15,000 lb Class B MH which is used in any kind of commercial enterprise that goes out of state is a CMV and will need everything except a CDL and apportioned tags. Yes, a medical card is needed for all CMV's even if a CDL is not a requirement. A 9,000 lb truck pulling a 4,000 lb trailer in any kind of commerce across a state line is a CMV. 9000+4000=13,000.