This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice questions. To pass, the applicant must answer at least 16 questions correctly. Each question has three or four possible answer choices. Test questions come from the Oregon Commercial Driver Manual. Questions come from chapters covering: Driving Safely, Air Brakes (if applicable), Combination Vehicles and Doubles and Triples. The Double/Triple endorsement can be used with the Class A CDL.
Number of Question
1. You must have an air brake endorsement:
You must take an air brakes knowledge test to become licensed to operate a vehicle that is equipped with air brakes, including an air over hydraulic braking system.
2. What can rust around the wheel nuts indicate?
Rust around wheel nuts can indicate that they are loose. If you observe rust, check the tightness of the nuts.
3. If turning to avoid a hazard:
If you are turning to avoid a hazard, do not apply the brakes while you are turning. This could easily lock the wheels and create a skid.
4. Poisonous fumes can enter the cab due to:
Defects in an exhaust system are very dangerous because they can cause poisonous fumes to enter the cab or sleeper berth.
5. When trying to avoid a hazard:
Stopping is not always the most effective response to a hazard. You can usually turn out of the path of a hazard more quickly than you can come to a complete stop. However, swerving is not without its hazards, as it may result in a rollover in a vehicle that is either top-heavy or pulling multiple trailers.
6. If coolant has to be added to a system without a recovery tank, you should:
Before adding coolant to a system without a recovery or overflow tank, you must turn the engine off and wait until it cools. Use gloves or a thick cloth to protect your hands. To release the pressure seal, turn the radiator cap slowly to the first stop.
7. When completing pre-trip inspections: