A commercial driver’s license (CDL) is required for drivers who want to operate trucks, buses, and other large vehicles. A CDL instructor teaches students how to operate these vehicles and pass the CDL exam. In this role, you work with students both in the classroom and on the road. Your job duties focus on teaching them to operate a vehicle safely in a structured area as well as on public roads, and to learn the skills necessary to pass their state’s CDL exam. CDL instructors must earn certification before they begin teaching at a truck driving school or vocational college.