CDL Air Brake - Commercial Driver's License Air Brakes Dual Air Brake Systems Questions and Answers

Question 1

What is the primary safety advantage of a dual air brake system?

Accepted Answer

It provides braking capability even if one of the two systems fails.

Answer

It allows the vehicle to stop in a shorter distance than a single system.

Answer

It eliminates the need for spring brakes.

Answer

It uses a single air tank, making it easier to maintain.

Question 2

A driver is operating a vehicle with a dual air brake system. The low air pressure warning light and buzzer activate. What is the minimum pressure remaining in the system for this to occur?

Accepted Answer

Before pressure drops below 60 psi

Answer

At approximately 100 psi

Answer

At or above 125 psi

Answer

When the pressure drops between 20-45 psi

Question 3

When conducting a pre-trip inspection on a dual air brake system, what is the minimum air pressure the compressor should build in both the primary and secondary systems before driving?

Accepted Answer

100 psi

Answer

60 psi

Answer

85 psi

Answer

125 psi

Question 4

In a typical dual air brake system on a two-axle truck, how are the two systems usually split?

Accepted Answer

One system operates the front axle, and the other operates the rear axle.

Answer

One system operates the left side brakes and the other operates the right side brakes.

Answer

Both systems operate all brakes simultaneously, with one as a backup.

Answer

One system operates the service brakes and the other operates the parking brake.

Question 5

While driving a truck with a dual air brake system, a failure occurs in the primary system. Which of the following is the most likely outcome?

Accepted Answer

Stopping distance will be increased, and the secondary system will still provide braking.

Answer

The parking brake will immediately apply automatically.

Answer

The brake pedal will feel solid, but the truck will not stop.

Answer

Both front and rear brakes will lose all braking power.

Question 6

During a static leak test with the brakes fully applied on a single vehicle with a dual air brake system, the air loss rate should not exceed:

Accepted Answer

3 psi in one minute

Answer

1 psi in one minute

Answer

2 psi in one minute

Answer

4 psi in one minute