CDL Emergency Handling Questions
Emergency handling covers what you do when something has already gone wrong: a skid, brakes that have faded on a long downgrade, or a situation where steering is a better answer than braking. The exam wants specific procedures here, and several of them are the opposite of instinct.
What the test asks about emergency handling
Take the drive-wheel braking skid. When the rear wheels lock, a bus or straight truck slides sideways in a spin out. With a trailer behind you, the skid lets the trailer push the towing vehicle sideways into a sudden jackknife. The correction the manual gives is to stop braking, which lets the rear wheels roll and grip again, and then counter-steer, because a vehicle coming back on course tends to keep turning and will skid the other way unless you turn the wheel back quickly. Coming off the brake in an emergency is not what anyone does naturally, which is exactly why it gets tested.
Where drivers lose marks
- Braking harder in a skid. For a drive-wheel braking skid the manual's first step is to stop braking so the rear wheels can turn again.
- Forgetting the counter-steer. Releasing the brake alone is half the procedure, and without the counter-steer you end up skidding in the opposite direction.
- Not knowing what causes front-wheel skids. Driving too fast for conditions causes most of them, with worn tread another cause.
- Treating escape ramps as a last resort you can work out on the day. The manual expects you to know where the ramps are on your route before you start down the grade.
How to study itLearn each emergency as a short ordered procedure, not a paragraph. Skid: stop braking, counter-steer. Downgrade: use a safe speed and the proper brake pattern rather than riding the brakes. Ordered steps are what the questions test.
50 Emergency Handling practice questions with answers
Every question below is followed by the correct answer and an explanation of why it is right. Read through them, then take the timed General Knowledge test to see how you do without the answers in front of you.
1. If an oncoming vehicle drifts into your lane, which direction should you steer to avoid a head-on collision?
Why: Always steer to the right. If you steer left, the other driver may realize their mistake and correct back into their lane, causing a collision. The right shoulder or ditch is usually the safest option.
2. What is the meaning of the acronym PASS when using a fire extinguisher?
Why: PASS stands for Pull the pin, Aim at the base of the fire, Squeeze the handle, and Sweep from side to side. This is the standard method for effectively using a fire extinguisher.
3. If your vehicle does not have ABS, what is the controlled braking method?
Why: Controlled braking involves applying the brakes as hard as you can without locking the wheels. Keep steering wheel movements very small while doing this.
4. If you have to stop on the shoulder of the road at night, what should you do immediately to warn other drivers before placing your triangles?
Why: You must turn on your four-way emergency flashers immediately to warn other drivers that your vehicle is stopped, while you prepare to place your warning devices.
5. What is the very first thing you should do if a front tire blows out while driving at highway speeds?
Why: If a front tire fails, the vehicle will pull strongly to the side of the blown tire. You must grip the steering wheel firmly and stay off the brakes until the vehicle slows down, as braking can cause loss of control.
6. Which type of fire should you NEVER use water to extinguish?
Why: Water can cause burning fuel to spread and conducts electricity, which can lead to a fatal shock. Never use water on electrical or flammable liquid fires.
7. If your vehicle stalls on railroad tracks and a train is approaching, what must you do immediately?
Why: If a train is coming, get out of the vehicle immediately. Run at an angle toward the direction the train is coming from, but away from the tracks. This keeps you safe from flying debris when the train hits your vehicle.
8. Which factor heavily influences a commercial vehicle's likelihood of rolling over in a curve?
Why: High speed in curves and a high center of gravity (top-heavy cargo) are the primary causes of commercial vehicle rollovers. Drivers must reduce speed before entering curves.
9. How should you handle an engine fire while on the road?
Why: For an engine fire, pull off the road safely, turn off the engine, and shoot the fire extinguisher through the louvers, radiator, or from the underside. Opening the hood provides oxygen and can cause the fire to flare up.
10. What does a B:C rated fire extinguisher mean?
Why: A B:C fire extinguisher is designed to work on electrical fires and burning liquids (such as fuel or grease). It should not be used on ordinary combustibles like wood or paper.
11. What should you do if your brakes fail while driving down a steep grade?
Why: If your brakes fail on a downgrade, you should look outside your vehicle for an escape ramp or an uphill open area. Escape ramps are designed to stop runaway vehicles safely.
12. What hazard is created when braking sharply while carrying a heavy liquid load in a tank trailer?
Why: Liquid surge is the movement of liquid in partially filled tanks. Heavy braking can cause a powerful forward surge that pushes the truck forward, even if the wheels are locked.
13. In an emergency, why might steering to avoid an obstacle be better than braking?
Why: Heavy vehicles take a long distance to stop. In many emergencies, you can steer around an obstacle in a shorter distance than it would take to bring the vehicle to a complete stop.
14. What should you do if your low air pressure warning alarm comes on while driving?
Why: A low air pressure warning indicates a significant loss of air. If the pressure falls too low, the spring brakes will apply automatically. You must stop safely while you still have control of the brakes.
15. When driving a vehicle with Anti-lock Braking Systems (ABS), how should you brake in an emergency situation?
Why: With ABS, you should brake as you normally would. Apply firm, steady pressure. The ABS will prevent the wheels from locking up while allowing you to maintain steering control.
16. When recovering from a skid on black ice, what is a key action to avoid?
Why: When sliding on black ice, you should absolutely avoid using the brakes. Braking will only lock the wheels further and ensure you completely lose control of the vehicle.
17. If your headlights suddenly fail at night, what is the safest immediate action?
Why: Headlight failure requires you to maintain visibility to other drivers and safely stop. Turn on your four-way flashers or turn signals and carefully pull off the roadway to investigate.
18. Which of the following is true regarding caring for the injured at an accident scene?
Why: Do not move a severely injured person unless there is an immediate danger of fire or oncoming traffic, as moving them can cause further injury.
19. What should you do if an aggressive driver or tailgater is following you too closely?
Why: If someone is tailgating you, you should increase your own following distance in front of you. This allows you to brake slowly if needed, preventing the tailgater from crashing into your rear.
20. When administering first aid to a bleeding victim at an accident scene, what is the best way to stop the bleeding?
Why: The most effective way to stop severe bleeding is to apply direct, steady pressure to the wound using a clean cloth or bandage.
21. How do you test if your fire extinguisher is ready for use before a trip?
Why: During a pre-trip inspection, you must ensure the fire extinguisher is properly mounted, fully charged (pressure gauge in the green zone), and has the safety pin in place.
22. If you experience a drive-wheel braking skid, what is the first action you should take to regain control?
Why: To correct a drive-wheel braking skid, you must stop braking to let the rear wheels roll again, and steer in the direction you want the vehicle to go.
23. What is the first thing you should do when arriving at the scene of an accident you are involved in?
Why: The very first priority at an accident scene is to protect the area. Move your vehicle to the side of the road if possible, turn on your flashers, and place warning triangles to prevent further crashes.
24. Which of the following describes hydroplaning?
Why: Hydroplaning occurs when water collects under the tires, lifting them off the surface of the road. This results in a total loss of steering and braking control.
25. How can you tell if your brakes are beginning to fade?
Why: Brake fade occurs when brakes overheat. You will notice that you have to press the pedal harder to achieve the same braking effect. If not addressed, it can lead to total brake failure.
26. What is the purpose of an escape ramp?
Why: Escape ramps use a long bed of loose, soft material (like gravel) to safely stop a heavy vehicle that has lost its braking ability on a steep downgrade.
27. If you must leave the roadway to avoid a collision, what should you do to safely return to the road?
Why: If you must leave the road, try to slow down to about 20 mph before returning. Then turn the steering wheel sharply to get back on the road safely, and quickly counter-steer to stay in your lane.
28. Which of the following is the most important rule when braking heavily to avoid a crash?
Why: When braking heavily, you must keep the vehicle in a straight line to maintain steering control and avoid skidding or jackknifing. Controlled or stab braking helps achieve this.
29. What is the most effective way to extinguish a tire fire?
Why: Water is the most effective way to put out a tire fire because it cools the tire. If water is not available, dirt can be used to smother it. Tires contain rubber which holds intense heat.
30. What is the most important reason for not braking hard during a tire blowout?
Why: Braking hard during a blowout can cause the vehicle to pull violently to the side of the blown tire, leading to a loss of control or a rollover.
31. Where should you place your emergency warning devices if you stop just over a hill or around a blind curve?
Why: If line of sight is obstructed by a hill or curve, you must move the rear-most warning device further back, up to 500 feet, to ensure approaching drivers have adequate warning.
32. Where should you place warning triangles if stopped on a two-lane road carrying traffic in both directions?
Why: On a two-lane road, place one triangle 10 feet from the front or rear corner, one 100 feet behind the vehicle, and one 100 feet ahead of the vehicle to warn traffic from both directions.
33. Where should you place your three emergency warning triangles if you must stop on the shoulder of a divided highway?
Why: On a divided highway or one-way road, warning devices must be placed 10 feet, 100 feet, and 200 feet toward the approaching traffic to provide adequate warning.
34. According to federal regulations, how much time do you have to place your emergency warning devices after stopping on the roadway or shoulder?
Why: You must place your warning devices (triangles, flares, or reflectors) within 10 minutes of stopping your vehicle on the street or highway.
35. Does Anti-lock Braking System (ABS) reduce your vehicle's stopping distance?
Why: ABS does not necessarily shorten your stopping distance. Its primary purpose is to prevent wheel lockup so you can steer around obstacles during an emergency braking situation.
36. What is the correct procedure for using a fire extinguisher on a fire?
Why: When using a fire extinguisher, you should aim at the base of the fire and use a sweeping motion from side to side until the fire is completely out.
37. How can you safely dry wet brakes after driving through heavy rain or deep water?
Why: To dry wet brakes, slow down, place the transmission in a low gear, and gently apply the brakes. This generates light heat that dries the moisture from the brake linings.
38. How do you recover from a trailer jackknife?
Why: The best way to stop a trailer from jackknifing is to release the brakes so the trailer wheels can grip the road again and roll straight.
39. What should you do if your hood flies up while driving?
Why: If the hood flies up, your forward vision will be blocked. Look through the gap at the bottom or lean out the window to see the road, turn on your hazard lights, and pull off safely.
40. What does a yellow ABS malfunction lamp on the instrument panel indicate?
Why: A yellow ABS light means the Anti-lock Braking System is not functioning. However, the vehicle will still have its regular braking system. You should drive normally but get the ABS repaired soon.
41. What is the primary cause of a front-wheel skid?
Why: Front-wheel skids are primarily caused by driving too fast for conditions, lack of tread on the front tires, or cargo improperly loaded too far back.
42. If you lose power steering due to engine failure, what will happen?
Why: If the engine dies, the power steering pump stops working. You will not lose steering completely, but it will require much more physical effort to turn the steering wheel.
43. If you are carrying hazardous materials and your vehicle catches fire, what should you do if the fire is spreading to the cargo?
Why: If a fire involves hazardous materials and is spreading, do not attempt to fight it. Evacuate the area, keep people away, and notify emergency personnel immediately.
44. What should you do if your vehicle begins to hydroplane?
Why: If you hydroplane, do not use the brakes. Release the accelerator and, if driving a manual transmission, push in the clutch. This allows the wheels to turn freely and regain contact with the road.
45. What is a common sign that you have experienced a tire blowout?
Why: A blowout is often preceded or accompanied by a loud bang. You may also feel a thumping vibration or notice the steering wheel feels heavy and pulls to one side.
46. What is the correct procedure for steering to avoid a crash?
Why: When making an evasive steering maneuver, keep both hands on the wheel and do not turn more than necessary. Avoid braking while turning, as it can cause the wheels to lock and result in a skid.
47. What is stab braking?
Why: Stab braking is applying the brakes fully until the wheels lock up, releasing them until the wheels start rolling again, and then reapplying them fully. This is used in vehicles without ABS.
48. If you notice a cargo fire in a closed van or box trailer, why should you keep the trailer doors closed?
Why: Opening the doors of a closed van or box trailer allows oxygen to enter, which will feed the fire and cause it to expand rapidly. Keep the doors closed and wait for firefighters.
49. Why is it dangerous to pump air brakes in an emergency?
Why: Fanning or pumping air brakes wastes air. If done repeatedly, it reduces air pressure in the tanks, which can cause the spring brakes to apply or lead to a total loss of braking ability.
50. In the event of an accident involving a hazardous materials spill, what document is crucial to provide to emergency responders?
Why: Shipping papers contain critical information about the hazardous materials you are carrying. Emergency responders need these to know exactly what risks are present and how to fight any fires.
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