CDL GENERAL KNOWLEDGE TEST 2026
QUESTIONS WITH VERIFIED ANSWERS
1. What is the minimum tread depth for front tires on a commercial vehicle?
A. 2/32 inch
B. 6/32 inch
C. 4/32 inch
D. 1/32 inch
Answer: C
Conceptual Explanation: Federal regulations require at least 4/32 inch tread depth in
every major groove on front tires and 2/32 inch on other tires.
2. How far ahead should a driver look while driving a commercial vehicle?
A. 5 to 8 seconds
B. 8 to 10 seconds
C. 20 to 25 seconds
D. 12 to 15 seconds
,Answer: D
Conceptual Explanation: Commercial drivers should look 12 to 15 seconds ahead, which
is about a quarter-mile at highway speeds.
3. When approaching a curve, when should you downshift?
A. While in the middle of the curve
B. Before entering the curve
C. As you exit the curve
D. Only if you feel the vehicle sliding
Answer: B
Conceptual Explanation: Downshifting should be done before entering a curve to ensure
you have power for acceleration and to maintain control.
4. What is the best way to handle a tailgater?
A. Step on your brakes quickly to warn them
B. Increase your speed to create distance
C. Flash your high beams
D. Increase your following distance to the vehicle ahead
Answer: D
, Conceptual Explanation: Increasing your following distance gives you more time to react,
preventing the need for sudden braking that the tailgater might not expect.
5. At what BAC (Blood Alcohol Concentration) is a commercial driver considered legally
intoxicated?
A. 0.04%
B. 0.01%
C. 0.08%
D. 0.10%
Answer: A
Conceptual Explanation: For CDL holders operating a commercial vehicle, the legal limit
for BAC is 0.04%.
6. What is the ‘total stopping distance’ comprised of?
A. Speed + Weight + Braking Distance
B. Reaction Distance + Braking Distance
C. Perception Distance + Braking Distance
D. Perception Distance + Reaction Distance + Braking Distance
Answer: D
QUESTIONS WITH VERIFIED ANSWERS
1. What is the minimum tread depth for front tires on a commercial vehicle?
A. 2/32 inch
B. 6/32 inch
C. 4/32 inch
D. 1/32 inch
Answer: C
Conceptual Explanation: Federal regulations require at least 4/32 inch tread depth in
every major groove on front tires and 2/32 inch on other tires.
2. How far ahead should a driver look while driving a commercial vehicle?
A. 5 to 8 seconds
B. 8 to 10 seconds
C. 20 to 25 seconds
D. 12 to 15 seconds
,Answer: D
Conceptual Explanation: Commercial drivers should look 12 to 15 seconds ahead, which
is about a quarter-mile at highway speeds.
3. When approaching a curve, when should you downshift?
A. While in the middle of the curve
B. Before entering the curve
C. As you exit the curve
D. Only if you feel the vehicle sliding
Answer: B
Conceptual Explanation: Downshifting should be done before entering a curve to ensure
you have power for acceleration and to maintain control.
4. What is the best way to handle a tailgater?
A. Step on your brakes quickly to warn them
B. Increase your speed to create distance
C. Flash your high beams
D. Increase your following distance to the vehicle ahead
Answer: D
, Conceptual Explanation: Increasing your following distance gives you more time to react,
preventing the need for sudden braking that the tailgater might not expect.
5. At what BAC (Blood Alcohol Concentration) is a commercial driver considered legally
intoxicated?
A. 0.04%
B. 0.01%
C. 0.08%
D. 0.10%
Answer: A
Conceptual Explanation: For CDL holders operating a commercial vehicle, the legal limit
for BAC is 0.04%.
6. What is the ‘total stopping distance’ comprised of?
A. Speed + Weight + Braking Distance
B. Reaction Distance + Braking Distance
C. Perception Distance + Braking Distance
D. Perception Distance + Reaction Distance + Braking Distance
Answer: D
