Sample Questions

CDL Sample Questions

6 practice questions with complete answer explanations.

Sample Questions

Question 1hours-of-service

Under federal Hours of Service rules, how many hours can a property-carrying driver drive after 10 consecutive hours off duty?

A.11 hours✓ Correct

B.10 hours

C.8 hours

D.14 hours

Explanation

Property HOS: 11-hour driving limit after 10 hours off. Passenger: 10 hours driving after 8 off.

Question 2inspection

During a pre-trip inspection, which tire condition requires the vehicle be taken out of service?

A.Tread depth less than 2/32 inch on a steer tire✓ Correct

B.Tread depth less than 1/32 inch on a drive tire

C.Any tire with a pressure below 90 PSI

D.A valve stem cap is missing

Explanation

Steer axle tires: minimum 4/32 inch; other tires: minimum 2/32 inch. Less than 2/32 on a steer = out of service.

Question 3air-brakes

If your truck has air brakes, the low air pressure warning must activate at:

A.60 psi✓ Correct

B.80 psi

C.40 psi

D.90 psi

Explanation

Low air warning: must activate before air pressure drops below 60 psi.

Question 4coupling

Before coupling to a trailer, you must check that the trailer kingpin is:

A.Straight and undamaged, with no cracks✓ Correct

B.Greased with axle grease

C.Locked into the fifth wheel

D.At least 4 inches above the fifth wheel

Explanation

Kingpin inspection: look for cracks, bends, or damage before coupling.

Question 5hazmat

When transporting Class 3 (Flammable Liquids) hazmat, placards are required when you carry:

A.Any amount that requires a placard✓ Correct

B.More than 1,000 pounds

C.More than 500 gallons

D.Only if crossing state lines

Explanation

Most hazmat classes require placards when carrying 1,001 lbs or more — but any amount of certain materials always requires placards.

Question 6space-management

The proper following distance at highway speeds for a truck is at least:

A.One second per 10 feet of vehicle length✓ Correct

B.Two seconds for all trucks

C.Three seconds flat

D.Four seconds at any speed

Explanation

Following distance formula: 1 second per 10 feet of vehicle length at 40+ mph, plus 1 extra second over 40 mph.

Test-Taking Tips

1.Your state's CDL manual is the only source you need — read it cover to cover.
2.Hours of Service rules are complex — make a cheat sheet with the key numbers (11h driving, 14h window, 10h reset, 70h in 8 days).
3.Air brakes endorsement: know the three brake tests (static, governor, low air warning).
4.For HazMat: memorize the 9 hazard classes and their placard requirements.
5.Use free CDL practice tests on DMV.org or cdlpracticetest.com — they mirror real exam format.
6.After passing knowledge tests, get hands-on driving hours with a CDL school or mentor before your skills test.

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