Handling Emergencies

Study questions with answers

7 sample Handling Emergencies questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.

1. 1. What is the "controlled braking" method for an emergency stop?

   Correct answer: Braking as firmly as possible short of locking the wheels, keeping steering inputs small

   With controlled braking you apply the brakes as hard as possible without locking the wheels while keeping steering movements small; if the wheels lock or you need to steer more, release and reapply.

   Source: Ohio CDL Manual — Section 5: Air Brakes

2. 2. What most commonly causes brakes to fade on a long downgrade?

   Correct answer: Excessive heat from overusing the service brakes

   Brake fade usually comes from excessive heat built up by overusing the service brakes instead of letting the engine do the braking. The heat changes the lining and expands the drums, cutting braking force.

   Source: Ohio CDL Manual — Section 5: Air Brakes

3. 3. While you are driving, the low-air-pressure warning suddenly lights up. What should you do?

   Correct answer: Stop and safely park as soon as possible, because there may be an air leak

   Stop and safely park as soon as possible, since there may be an air leak. You can still brake with the air that remains, so it is far safer to stop before pressure drops to where the spring brakes apply.

   Source: Ohio CDL Manual — Section 5: Air Brakes

4. 4. How is "stab braking" performed in an emergency stop?

   Correct answer: Push the brakes all the way, release when the wheels lock, then reapply fully once they roll

   Push the brakes all the way, release them when the wheels lock, and reapply fully once the wheels start rolling again. Wait for the wheels to roll first, since that can take up to a second.

   Source: Ohio CDL Manual — Section 5: Air Brakes

5. 5. If air keeps leaking away, spring brakes on a tractor or straight truck will come fully on once pressure drops into what range?

   Correct answer: 20 to 45 psi

   On tractors and straight trucks the spring brakes apply when pressure falls to somewhere between 20 and 45 psi, typically 20 to 30 psi.

   Source: Ohio CDL Manual — Section 5: Air Brakes

6. 6. When the low-air warning first lights up and the buzzer sounds while driving, what does the manual say to do?

   Correct answer: Pull over and stop safely at once, while air still remains to work the brakes

   Don't wait for the spring brakes to set by themselves. Get parked safely at once, while enough air still remains to let you work the brakes.

   Source: Ohio CDL Manual — Section 5: Air Brakes

7. 7. What is the main benefit that antilock brakes (ABS) provide?

   Correct answer: They keep the wheels from locking up so you stay in control during hard braking

   ABS keeps the wheels from locking up during hard braking so you can keep control and steer around trouble. It is an addition to your normal brakes, activating only when a wheel is about to lock.

   Source: Ohio CDL Manual — Section 5: Air Brakes