CDL GENERAL KNOWLEDGE FINAL
2026 TEST QUESTIONS AND ANSWERS
1. What is the minimum tread depth required for steering axle tires on a commercial vehicle?
A. 2/32 inch
B. 1/32 inch
C. 6/32 inch
D. 4/32 inch
Answer: D
Conceptual Explanation: Federal regulations require at least 4/32 inch of tread depth in
every major groove on steering tires; all other tires require 2/32 inch.
2. When driving at 55 mph on dry pavement, what is the average total stopping distance for a
heavy vehicle?
A. Double the length of a football field
B. Half the length of a football field
C. The length of a football field (about 300 feet)
,D. Four times the length of a football field
Answer: C
Conceptual Explanation: Total stopping distance at 55 mph involves perception distance,
reaction distance, and braking distance, totaling roughly 290 to 300 feet.
3. How far ahead should a driver look while driving at highway speeds?
A. 5 to 8 seconds
B. 12 to 15 seconds
C. 20 to 25 seconds
D. 2 to 4 seconds
Answer: B
Conceptual Explanation: Looking 12 to 15 seconds ahead allows a driver to identify and
adjust to hazards before they become critical; at highway speeds, this is about a quarter
mile.
4. Which of the following is NOT part of the basic emergency equipment required in a
commercial vehicle?
A. Three reflective triangles
B. A first aid kit
C. A fire extinguisher
D. Spare electrical fuses
, Answer: B
Conceptual Explanation: While recommended, a first aid kit is not federally mandated
emergency equipment for all commercial vehicles, unlike triangles, fuses, and
extinguishers.
5. What is the safest way to back a commercial vehicle?
A. Back as quickly as possible to clear the roadway
B. Back towards the passenger’s side to see the blind spot better
C. Back towards the driver’s side whenever possible
D. Rely solely on your mirrors
Answer: C
Conceptual Explanation: Backing toward the driver’s side allows you to see the rear of the
vehicle more clearly by looking out the side window.
6. What is ‘off-tracking’?
A. When the rear wheels follow a different path than the front wheels during a turn
B. When the trailer disconnects from the fifth wheel
C. When the vehicle pulls to one side during braking
D. Losing traction on a wet surface
Answer: A
2026 TEST QUESTIONS AND ANSWERS
1. What is the minimum tread depth required for steering axle tires on a commercial vehicle?
A. 2/32 inch
B. 1/32 inch
C. 6/32 inch
D. 4/32 inch
Answer: D
Conceptual Explanation: Federal regulations require at least 4/32 inch of tread depth in
every major groove on steering tires; all other tires require 2/32 inch.
2. When driving at 55 mph on dry pavement, what is the average total stopping distance for a
heavy vehicle?
A. Double the length of a football field
B. Half the length of a football field
C. The length of a football field (about 300 feet)
,D. Four times the length of a football field
Answer: C
Conceptual Explanation: Total stopping distance at 55 mph involves perception distance,
reaction distance, and braking distance, totaling roughly 290 to 300 feet.
3. How far ahead should a driver look while driving at highway speeds?
A. 5 to 8 seconds
B. 12 to 15 seconds
C. 20 to 25 seconds
D. 2 to 4 seconds
Answer: B
Conceptual Explanation: Looking 12 to 15 seconds ahead allows a driver to identify and
adjust to hazards before they become critical; at highway speeds, this is about a quarter
mile.
4. Which of the following is NOT part of the basic emergency equipment required in a
commercial vehicle?
A. Three reflective triangles
B. A first aid kit
C. A fire extinguisher
D. Spare electrical fuses
, Answer: B
Conceptual Explanation: While recommended, a first aid kit is not federally mandated
emergency equipment for all commercial vehicles, unlike triangles, fuses, and
extinguishers.
5. What is the safest way to back a commercial vehicle?
A. Back as quickly as possible to clear the roadway
B. Back towards the passenger’s side to see the blind spot better
C. Back towards the driver’s side whenever possible
D. Rely solely on your mirrors
Answer: C
Conceptual Explanation: Backing toward the driver’s side allows you to see the rear of the
vehicle more clearly by looking out the side window.
6. What is ‘off-tracking’?
A. When the rear wheels follow a different path than the front wheels during a turn
B. When the trailer disconnects from the fifth wheel
C. When the vehicle pulls to one side during braking
D. Losing traction on a wet surface
Answer: A
