CDL General Knowledge Test
Emergencies and skids: practice questions
Our CDL General Knowledge bank has 19 questions on this topic. Here are 4 of them with answers; the full mock exam draws from every topic, like the real one.
Question 1
What is a 'jackknife'?
- When a trailer's drive wheels lock and the tractor and trailer fold toward each other
- A turn signal
- A type of knife
- A coupling tool
Show the answer
A. When a trailer's drive wheels lock and the tractor and trailer fold toward each other — Release the brakes to regain traction.
Question 2
If a tire blows out, what should you do first?
- Hold the steering wheel firmly and stay off the brake until the vehicle has slowed
- Accelerate
- Turn sharply off the road
- Brake hard immediately
Show the answer
A. Hold the steering wheel firmly and stay off the brake until the vehicle has slowed — Braking hard can cause loss of control.
Question 3
If your engine overheats on the road, what is the safe way to check the coolant?
- Keep driving
- Let the engine cool before opening the radiator cap
- Open the cap immediately
- Pour cold water over the hot engine block to cool it down quickly
Show the answer
B. Let the engine cool before opening the radiator cap — Hot coolant under pressure can cause severe burns.
Question 4
What should you do if your vehicle gets stuck on the railroad tracks?
- Get out and away from the tracks immediately, and call the emergency number posted at the crossing
- Try to push it
- Walk along the tracks
- Stay in the cab and wait
Show the answer
A. Get out and away from the tracks immediately, and call the emergency number posted at the crossing — Move away at an angle toward the train to avoid debris.