That depends on the state it's registered in.
I thought the selling owner needs to smog vehicle before selling it- the new owner does not need to re-smog the car.
Yes, commericial vehicles in Washington do require smog checks. Where there are some states that don't, Washington is one that requires for a vehicle to receive one every 2 years.
No, it will not pass the smog test with a defective or removed O2 sensor.
vehicle was smogged last year and now notified to smog it again this year
No, there will be no problem at the DMV. The important thing is that the DMV has received your vehicle's smog check certificate number and the vehicle has passed. The reason for the smog test is simply for smog check data which is obtained by Sacramento and used for analysis.
The "short" answer is- Inefficient combustion in the vehicle's engine produces chemicals that when exposed to sun-light create smog.
Smog
The Mercury Mariner is a passenger vehicle. It's only a commercial vehicle if used for commercial purposes. If it has passenger plates, it is not considered a commercial vehicle, and is not subject to commercial vehicle restrictions.
When it is used for commercial purposes.
Any vehicle that is going to be used for commercial purposes would qualify for a commercial vehicle loan. You will also have to have commercial insurance on the vehicle.
No. A commercial vehicle is defined as a motor vehicle used for public transportation or cargo transportation. Generally, A vehicle is designated "commercial" when it is titled or registered to a company. A taxi cab is a commercial vehicle. A police car is not.
To track a commercial vehicle, you must have a vehicle tracking system, much like a GPS. With one of these systems, it is easy to use and track the commercial vehicle.