CDL Pre-Trip Inspection: The 7-Step Method
Updated October 27, 2026
Every CDL driver must inspect the vehicle before a trip, and the pre-trip inspection is part of the skills test as well as the General Knowledge test. The CDL manual teaches a 7-step method so you don’t miss anything. Here’s the method and the key things to check, followed by free practice questions.
These follow the model CDL manual most states use. Your state’s manual and its skills test checklist are the final word.
The 7-step inspection method
- Vehicle overview: review the last vehicle inspection report and look for leaks, damage and leaning.
- Check the engine compartment: fluid levels, belts, hoses and wiring.
- Start the engine and inspect inside the cab: gauges, controls, mirrors, windshield, wipers and emergency equipment.
- Turn off the engine and check the lights: headlights, high beams and four-way flashers.
- Do a walk-around inspection: tires, wheels, brakes, suspension, steering, lights and reflectors, and cargo securement.
- Check the signal lights: turn signals and brake lights.
- Start the engine and check the brake system: hydraulic or air brakes, the parking brake and the service brakes.
Key things to check
| Part | Look for |
|---|---|
| Tires | At least 4⁄32 inch of tread on steering tires and 2⁄32 inch on others; no cuts, bulges or mismatched sizes; correct inflation |
| Wheels and rims | Missing or loose lug nuts, rust trails around nuts, cracks |
| Brakes | Cracked drums, worn linings, loose or missing parts, air leaks |
| Steering | Excessive play, loose or missing parts |
| Suspension | Broken or missing leaf springs, leaking shock absorbers |
| Emergency equipment | Fire extinguisher, spare fuses (if needed) and three reflective warning triangles |
Free pre-trip inspection practice questions
-
What is the minimum tread depth for tires that are not on the steering axle?Answer: BTires other than the steering axle's need at least 2/32 inch of tread. Steering axle tires need at least 4/32 inch in every major groove.
-
During a walk-around inspection, you see rust trails around a wheel's lug nuts. What might this mean?Answer: ARust trails around lug nuts can mean the nuts are loose. Check them and have them corrected before driving.
-
Which emergency equipment must you have?Answer: CYou must carry a fire extinguisher and warning devices, such as three reflective triangles, plus spare fuses if the vehicle uses them.
-
What is the first step of the 7-step inspection method?Answer: BThe method starts with a vehicle overview: approach the vehicle looking for problems and review the last vehicle inspection report.
-
Which tire condition means the tire is unsafe to use?Answer: DBulges, cuts and exposed cords mean a tire is unsafe. 5/32 inch of tread is above the steering-axle minimum, and correct inflation and matching sizes are what you want.
-
When checking the steering system, what should you look for?Answer: AToo much steering wheel play, or loose, missing or damaged steering parts, can cause loss of control and must be fixed before driving.
-
When should you check tire pressure for an accurate reading?Answer: DTires heat up while driving, which raises pressure. Check pressure with a gauge when the tires are cold for an accurate reading.
-
During the engine compartment check, what should you look for on the drive belts?Answer: ACheck that belts are snug, not too loose, and free of cracks, frays and wear.
-
Which is a problem with a leaf spring during inspection?Answer: BCracked, broken, missing or shifted spring leaves can lead to loss of control. The vehicle shouldn't be driven until they're fixed.
-
Why should you check that the windshield wipers work?Answer: CWorking wipers and washers are needed to see clearly in bad weather. Check the wiper blades, arms and washer fluid.
-
During the walk-around, what should you check on the mud flaps?Answer: DMud flaps should be secure and not damaged, and they shouldn't drag on the ground.
-
What should you check about the exhaust system?Answer: AExhaust leaks can let carbon monoxide into the cab, and loose parts can fall off. Check for leaks and secure mounting.
-
When checking the steering system, what is excessive play in a steering wheel of 20 inches in diameter?Answer: BThe model CDL manual says that for a 20-inch steering wheel, more than about 2 inches of free play before the front wheels move makes it hard to steer.
-
Why should you look under the vehicle for fresh leaks during the overview?Answer: CFresh puddles of oil, coolant, grease or fuel under the vehicle can mean a leak that needs repair before the trip.
-
During the in-cab check, what should the oil pressure gauge do after the engine starts?Answer: DOil pressure should come up to normal within seconds after the engine starts. If it doesn't, stop the engine to avoid damage.
Pass your CDL permit test on the first try
- All 215 questions for General Knowledge, Air Brakes, Combination Vehicles and Hazmat
- An explanation for every answer, from the CDL manual and federal rules
- Unlimited practice tests for each knowledge test, scored like the real one (80% to pass)