Michigan CDL — Air Brakes: Parking & Stopping Practice Test

Question 1

When should you skip setting the parking brakes and use wheel chocks instead?

Accepted Answer

When the brakes are very hot from a steep grade, or very wet in freezing temperatures — Very hot brakes can be damaged by the parking brake, and wet brakes in freezing weather can freeze and trap the vehicle; in those cases let them cool or dry and chock the wheels.

Answer

Any time you park on level ground

Answer

Whenever the engine is running

Answer

Only when the tanks are fully charged

Question 2

Why should you avoid pressing the brake pedal while the spring brakes are already applied?

Accepted Answer

The combined spring and air forces could damage the brakes — With the spring brakes set, adding pedal (air) force stacks the two forces together and can damage the brakes, so it is best to never do it.

Answer

It empties the alcohol evaporator

Answer

It disables the ABS warning lamp

Answer

It makes the governor cut out too early

Question 3

What must you always do before leaving your vehicle unattended?

Accepted Answer

Apply the parking brakes or chock the wheels — An unattended vehicle can roll away and cause injury or damage, so always set the parking brakes or chock the wheels before you walk away.

Answer

Drain the alcohol evaporator

Answer

Leave the engine running to keep pressure up

Answer

Release the spring brakes

Question 4

What is a modulating control valve used for on some air brake vehicles?

Accepted Answer

To apply the spring brakes gradually if the service brakes fail — A spring-loaded modulating handle lets the driver bring the spring brakes on little by little for a controlled stop if the service brakes quit; the farther the lever moves, the harder they apply.

Answer

To drain the air tanks automatically

Answer

To warn the driver of low air pressure

Answer

To cool the brake drums on a downgrade

Question 5

On newer air brake vehicles, what does the parking brake control usually look like?

Accepted Answer

A yellow, diamond-shaped push-pull knob — Newer vehicles use a yellow, diamond-shaped push-pull knob: pull it out to set the parking (spring) brakes and push it in to release them.

Answer

A round blue push button

Answer

A red octagonal lever

Answer

A green sliding switch

Parking & Stopping

Study questions with answers

1. When should you skip setting the parking brakes and use wheel chocks instead?

2. Why should you avoid pressing the brake pedal while the spring brakes are already applied?

3. What must you always do before leaving your vehicle unattended?

4. What is a modulating control valve used for on some air brake vehicles?

5. On newer air brake vehicles, what does the parking brake control usually look like?

More CDL — Air Brakes topics

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