Double
Directions
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 four possible answer choices. Test questions come from the North Dakota Commercial Driver Guide. Questions come from chapters covering: Driving Safely, Transporting Cargo Air Brakes (if applicable), Combination Vehicles and Doubles and Triples. The Double/Triple endorsement can be used with the Class A CDL.
Passing grade:
Belts in the engine compartment should be:
Explanation
When inspecting your vehicle's engine, check the belts for tightness and excessive wear. The amount of "give" that is safe for each belt in a given engine will vary, so learn what is appropriate for your vehicle.
Too little weight on a steering axle can result in:
Explanation
The weight of cargo in a vehicle needs to be balanced appropriately so that it does not interfere with the vehicle's safe handling. For example, if cargo is placed too far to the rear of a vehicle, the front axle will be under-weighted and the front wheels may not have enough traction for the driver to steer safely.
A vehicle stopped at a green light may indicate that the driver:
Explanation
It is important to observe other drivers' actions and identify clues that a person could be driving impaired. Drivers who have had too much to drink, are sleepy, are on drugs, or are ill can present hazards to other drivers. One sign that a driver may be impaired is that they stop in inappropriate places, such as at green traffic lights.
What is the Gross Vehicle Weight Rating (GVWR)?
Explanation
The Gross Vehicle Weight (GVW) is the total weight of a single vehicle plus its load. The Gross Vehicle Weight Rating (GVWR) is the maximum combined weight of a vehicle and its cargo that is permitted and specified by the manufacturer.
The emergency air line:
Explanation
The emergency air line (also known as the supply line) has two functions. The first is to supply air to the trailer air tanks on a combination vehicle, and the second is to control the emergency brakes.
When driving down a steep grade:
Explanation
When driving down a steep grade, you should rely primarily on the braking effect of the engine to slow down. To prevent overheating, use your brakes only as a supplement to this slowing technique.
What can happen if parking brakes are used in very wet weather with temperatures below freezing?
Explanation
