Final answer:
CDL airbrake systems must include a brake pedal, a supply pressure gauge, and a stop light switch, which is answer 4) all of the above. These components ensure safe operation and stopping of commercial vehicles.
Step-by-step explanation:
The student asked about the components that CDL airbrake systems must contain. Commercial Driver's License (CDL) airbrake systems are an essential safety feature on heavy commercial vehicles, and it is crucial for these systems to have several components to operate correctly and safely. The answer to the question is 4) all of the above, which means that CDL airbrake systems must contain a brake pedal, a supply pressure gauge, and a stop light switch.
In order to ensure the safe operation of a vehicle with an airbrake system, especially in calculating stopping distances, we need to know the following: the distance the driver covers before hitting the brakes, how long it takes the truck to stop after hitting the brakes, and the total distance the truck covers to stop. All of these factors are crucial in understanding the performance and safety of airbrake systems on commercial vehicles.