Do you currently have car insurance? Yes I have insurance. Great, you're all set! Click here if you still want to compare rates. No, I need insurance and I want to compare options. Before you start the test, please answer the following question regarding your insurance status. Without insurance you will not be able to drive in California Question Which gas would cause concern due to a faulty exhaust system? Answers Oxygen Carbon monoxide Nitrogen Explanation A leaking exhaust system can introduce carbon monoxide, which is poisonous, into the cab or sleeper berth. Take a FREE Practice Test Now This questions appears in the following tests: Arkansas Knowledge Test Class A , New Hampshire Knowledge Test Class A , Maine Knowledge Test Class B , Michigan Knowledge Test Class B , New Mexico Double , Vermont Double , Alabama Tank , Kentucky Passenger , South Dakota Passenger ,