On a cold day you drive with the heater on. You hear a new, loud roar from under the car, and after a while you feel drowsy and dizzy. What should you do?

Correct answer: Pull off, park, turn off the engine, open the windows, and have the exhaust checked.

Why

Carbon monoxide from the engine has no color, smell or taste, and it can kill. It is most likely to enter the car when the heater runs, when the exhaust system is damaged or when you sit in heavy traffic, and it can collect in the back seat where children ride. Oklahoma law requires a muffler in good working order and an engine that does not let out too many fumes, so have the exhaust system checked on a regular schedule.

Verified against Oklahoma Driver Manual · Avoid Carbon Monoxide Poisoning · p. 12, 60