Commercial Driver License (CDL) Skills Test Verified
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded
A+
1. Before starting a vehicle, a CDL driver must ensure:
A. The parking brake is released
B. The transmission is in gear
C. The parking brake is set
D. The clutch is depressed
Answer: C
The parking brake must be set to prevent unintended vehicle
movement during startup.
2. During a pre-trip inspection, which component should be
checked for air leaks?
A. Exhaust system
B. Air brake hoses and lines
C. Fuel tank
D. Radiator
Answer: B
Air brake hoses must be free from leaks to maintain proper braking
pressure.
3. What is the minimum tread depth required on steering axle
tires?
A. 1/32 inch
B. 4/32 inch
,C. 2/32 inch
D. 3/32 inch
Answer: B
Federal regulations require at least 4/32 inch tread depth on steering
axle tires.
4. When checking brake slack adjusters, they should not move
more than:
A. ½ inch
B. 1 inch
C. 2 inches
D. ¼ inch
Answer: B
Excessive movement indicates the brakes are out of adjustment.
5. Which item must be free of cracks, bends, or illegal welds?
A. Mirrors
B. Frame and cross members
C. Windshield
D. Seat mounts
Answer: B
Structural damage to the frame can compromise vehicle safety.
6. While inspecting lights, what must you verify?
A. Color only
B. Brightness only
C. Proper color, cleanliness, and operation
D. Lens size
,Answer: C
Lights must function correctly, be clean, and display the proper color.
7. What is the first step in the air brake check (static test)?
A. Start engine
B. Build air pressure to governor cut-out
C. Release parking brake
D. Pump brake pedal
Answer: B
Air pressure must reach normal operating range before testing for
leaks.
8. During the air leakage test, maximum allowable loss for a
combination vehicle is:
A. 2 psi per minute
B. 4 psi per minute
C. 6 psi per minute
D. 8 psi per minute
Answer: B
Combination vehicles are allowed up to 4 psi air loss per minute.
9. The low-air warning device must activate by:
A. 80 psi
B. 70 psi
C. 60 psi
D. 40 psi
, Answer: C
Federal standards require a warning before pressure drops below
safe levels.
10. The parking brake should engage automatically at
approximately:
A. 60 psi
B. 45 psi
C. 20–40 psi
D. 10 psi
Answer: C
Spring brakes engage automatically when air pressure drops to this
range.
11. What should you inspect on leaf springs?
A. Paint color
B. Cracks, missing leaves, or shifted position
C. Tire pressure
D. Oil residue
Answer: B
Damaged suspension components affect vehicle stability.
12. Steering linkage components must be:
A. Painted
B. Greased daily
C. Secure, not worn, and properly mounted
D. Flexible
Questions, Correct Answers, and Detailed
Explanations for Science Students||Already Graded
A+
1. Before starting a vehicle, a CDL driver must ensure:
A. The parking brake is released
B. The transmission is in gear
C. The parking brake is set
D. The clutch is depressed
Answer: C
The parking brake must be set to prevent unintended vehicle
movement during startup.
2. During a pre-trip inspection, which component should be
checked for air leaks?
A. Exhaust system
B. Air brake hoses and lines
C. Fuel tank
D. Radiator
Answer: B
Air brake hoses must be free from leaks to maintain proper braking
pressure.
3. What is the minimum tread depth required on steering axle
tires?
A. 1/32 inch
B. 4/32 inch
,C. 2/32 inch
D. 3/32 inch
Answer: B
Federal regulations require at least 4/32 inch tread depth on steering
axle tires.
4. When checking brake slack adjusters, they should not move
more than:
A. ½ inch
B. 1 inch
C. 2 inches
D. ¼ inch
Answer: B
Excessive movement indicates the brakes are out of adjustment.
5. Which item must be free of cracks, bends, or illegal welds?
A. Mirrors
B. Frame and cross members
C. Windshield
D. Seat mounts
Answer: B
Structural damage to the frame can compromise vehicle safety.
6. While inspecting lights, what must you verify?
A. Color only
B. Brightness only
C. Proper color, cleanliness, and operation
D. Lens size
,Answer: C
Lights must function correctly, be clean, and display the proper color.
7. What is the first step in the air brake check (static test)?
A. Start engine
B. Build air pressure to governor cut-out
C. Release parking brake
D. Pump brake pedal
Answer: B
Air pressure must reach normal operating range before testing for
leaks.
8. During the air leakage test, maximum allowable loss for a
combination vehicle is:
A. 2 psi per minute
B. 4 psi per minute
C. 6 psi per minute
D. 8 psi per minute
Answer: B
Combination vehicles are allowed up to 4 psi air loss per minute.
9. The low-air warning device must activate by:
A. 80 psi
B. 70 psi
C. 60 psi
D. 40 psi
, Answer: C
Federal standards require a warning before pressure drops below
safe levels.
10. The parking brake should engage automatically at
approximately:
A. 60 psi
B. 45 psi
C. 20–40 psi
D. 10 psi
Answer: C
Spring brakes engage automatically when air pressure drops to this
range.
11. What should you inspect on leaf springs?
A. Paint color
B. Cracks, missing leaves, or shifted position
C. Tire pressure
D. Oil residue
Answer: B
Damaged suspension components affect vehicle stability.
12. Steering linkage components must be:
A. Painted
B. Greased daily
C. Secure, not worn, and properly mounted
D. Flexible
