CDL CLASS B GENERAL KNOWLEDGE EXAM
(2026 EDITION) ANSWERS AND
RATIONALES ARE PROVIDED AT THE END.
Section 1: General Knowledge (All CDL Classes)
1. When a vehicle's engine stalls on a railroad track and you cannot
restart it, you should:
a) Stay in the vehicle and call for help
b) Get everyone out and far away from the tracks, then call 911
c) Push the vehicle off the tracks immediately
d) Flag down the train with a white cloth
2. The minimum tread depth for the front tires of a commercial
vehicle is:
a) 2/32 inch
b) 4/32 inch
c) 6/32 inch
d) 8/32 inch
3. What is the best way to stop on a wet or icy road?
a) Apply steady, firm pressure to brakes
b) Pump brakes rapidly
c) Use engine braking only
d) Brake normally, but start earlier and more gently
,4. You are driving a 30-foot straight truck at 55 mph. How much space
should you keep between you and the vehicle ahead?
a) 2 seconds
b) 3 seconds
c) 4 seconds
d) 5 seconds
5. Which of the following is a sign of a brake failure?
a) Squeaking when brakes are applied
b) Brake pedal goes to the floor
c) Brake pedal feels spongy
d) All of the above
6. When you double-clutch, you:
a) Press the clutch twice before each shift
b) Press clutch, shift to neutral, release clutch, rev engine, press
clutch, shift to next gear
c) Press clutch twice for downshifts only
d) Avoid using the clutch for upshifts
7. The parking brake should be used:
a) Only on steep hills
b) Any time you park the vehicle
c) Only when the air pressure is below 60 psi
d) Only in emergencies
8. What is the effect of overloading a vehicle?
a) Harder steering and increased brake wear
b) Better fuel economy
c) Easier turning
d) No effect on stability
, 9. Hydroplaning can occur at speeds as low as:
a) 20 mph
b) 30 mph
c) 45 mph
d) 55 mph
10. If your vehicle gets stuck on a railroad track, you should:
a) Stay in the cab and try to restart
b) Uncouple the trailer if possible
c) Get all passengers out and move away at a 45-degree angle toward
the train
d) Wave down the train with a flashlight
11. What is the legal maximum blood alcohol concentration (BAC) for
commercial drivers?
a) 0.08%
b) 0.04%
c) 0.02%
d) 0.00%
12. A CMV driver caught with a BAC of 0.04% or higher will be placed
out of service for how long?
a) 8 hours
b) 24 hours
c) 48 hours
d) 30 days
13. When driving through a construction zone, you should:
a) Speed up to get through quickly
b) Ignore reduced speed limits if no workers are present
(2026 EDITION) ANSWERS AND
RATIONALES ARE PROVIDED AT THE END.
Section 1: General Knowledge (All CDL Classes)
1. When a vehicle's engine stalls on a railroad track and you cannot
restart it, you should:
a) Stay in the vehicle and call for help
b) Get everyone out and far away from the tracks, then call 911
c) Push the vehicle off the tracks immediately
d) Flag down the train with a white cloth
2. The minimum tread depth for the front tires of a commercial
vehicle is:
a) 2/32 inch
b) 4/32 inch
c) 6/32 inch
d) 8/32 inch
3. What is the best way to stop on a wet or icy road?
a) Apply steady, firm pressure to brakes
b) Pump brakes rapidly
c) Use engine braking only
d) Brake normally, but start earlier and more gently
,4. You are driving a 30-foot straight truck at 55 mph. How much space
should you keep between you and the vehicle ahead?
a) 2 seconds
b) 3 seconds
c) 4 seconds
d) 5 seconds
5. Which of the following is a sign of a brake failure?
a) Squeaking when brakes are applied
b) Brake pedal goes to the floor
c) Brake pedal feels spongy
d) All of the above
6. When you double-clutch, you:
a) Press the clutch twice before each shift
b) Press clutch, shift to neutral, release clutch, rev engine, press
clutch, shift to next gear
c) Press clutch twice for downshifts only
d) Avoid using the clutch for upshifts
7. The parking brake should be used:
a) Only on steep hills
b) Any time you park the vehicle
c) Only when the air pressure is below 60 psi
d) Only in emergencies
8. What is the effect of overloading a vehicle?
a) Harder steering and increased brake wear
b) Better fuel economy
c) Easier turning
d) No effect on stability
, 9. Hydroplaning can occur at speeds as low as:
a) 20 mph
b) 30 mph
c) 45 mph
d) 55 mph
10. If your vehicle gets stuck on a railroad track, you should:
a) Stay in the cab and try to restart
b) Uncouple the trailer if possible
c) Get all passengers out and move away at a 45-degree angle toward
the train
d) Wave down the train with a flashlight
11. What is the legal maximum blood alcohol concentration (BAC) for
commercial drivers?
a) 0.08%
b) 0.04%
c) 0.02%
d) 0.00%
12. A CMV driver caught with a BAC of 0.04% or higher will be placed
out of service for how long?
a) 8 hours
b) 24 hours
c) 48 hours
d) 30 days
13. When driving through a construction zone, you should:
a) Speed up to get through quickly
b) Ignore reduced speed limits if no workers are present
