North Carolina CDL Practice Test

Not quite. The answer is 4/32 inch

Steering axle tires must have a tread depth of at least 4/32 inch. All other tires must have a tread depth of at least 2/32 inch.

Not quite. The answer is Ending a backing exercise while over a boundary line

Any of a variety of certain actions or inactions on your part can cause you to fail the entire CDL skills test. Of the four choices here, you must demonstrate to your test examiner that you can exit your vehicle safely whenever you have to. This includes properly securing the vehicle by setting the parking brakes and taking the ignition key with you. If you don't, you will automatically fail the entire CDL skills test. Also, failure to perform every one of the braking tests required for your vehicle, whether it's equipped with air brakes or hydraulic brakes, will constitute an automatic failure. Finally, overrunning a curb or sidewalk even slightly during the road test will also constitute an automatic failure. On the other hand, attempting to end a backing exercise while you're over a boundary line will lose you points, but it's not necessarily an automatic failure. Your examiner will tell you to move your vehicle inside the boundary lines, and your skills test will continue.

Not quite. The answer is Poisonous fumes can enter the cab or sleeping compartment.

The exhaust system is designed to help remove toxic gases produced by the engine. A leak in the exhaust system can allow poisonous carbon monoxide (CO) to seep into the cab or sleeping compartment. A buildup of CO is more likely in cold weather, when you may have the cab windows closed.

Not quite. The answer is the vehicle does not require placards.

You must have a hazardous materials endorsement on your CDL to drive a vehicle that is placarded for hazardous materials. However, not all packages of hazardous materials require placarding your vehicle. Federal regulation 49 CFR 172.500 exempts certain amounts and types of hazardous materials from placarding, but states may impose more stringent requirements. Check with the North Carolina Department of Transportation.

Not quite. The answer is 2; 2

Under federal regulations, a "large boulder" has a volume of more than 2 cubic meters or weighs more than 11,000 pounds. Each large boulder must be supported on at least two pieces of hardwood blocking that extend the full width of the boulder. Each cubic-shaped boulder must be secured with two or more chains placed transversely across the vehicle and as close as possible to the hardwood blocking. Each non-cubic-shaped boulder must be secured with two or more chains forming an "X" pattern over the boulder and passing over the center of the boulder. These two chains must be attached to each other at their intersection. If the boulder is non-cubic shaped and has an unstable base, it must be secured with one chain over the top of the boulder and four chains attached to that chain to block the boulder from moving.

Source: 49 CFR 393.136

Not quite. The answer is Flashing your brake lights to stop someone from tailgating

Use your headlights during times of lower visibility. Use your brake lights only to warn other drivers that you are preparing to slow down or stop, or there is a hazard ahead for which you'll have to slow down. If you're being tailgated, avoid such tricks as flashing your brake lights. Handle tailgaters in a different way: Keep right and increase your following distance.

Not quite. The answer is The maximum allowed weight of a vehicle and its load

The Gross Vehicle Weight (GVW) is the actual weight of a single vehicle plus its load, at some point in time. The Gross Vehicle Weight Rating (GVWR) is the maximum combined weight of a vehicle and its cargo, that is permitted and specified by the vehicle's manufacturer.

Not quite. The answer is Both of the above

There are many things you must check during your pre-trip inspection. During Step 1 (Vehicle Overview) of the Seven-Step Inspection Method, check the condition of the windshield wipers. During Step 4 (Turn Off Engine and Check Lights) and Step 5 (Walk-Around Inspection), you'll check that the lights are working.

Not quite. The answer is Gently apply the brakes while driving through the water.

If you must drive through water, slow down, shift into a low gear, and keep applying the brakes gently to prevent water, mud, or other contaminants from getting into the brakes.

Not quite. The answer is up to 500 feet behind the vehicle.

According to federal regulation 49 CFR 392.22, if you must stop beyond a curve or the crest of a hill that obstructs the view of your vehicle, you must set out one warning device (such as a reflective triangle) 10 feet behind your vehicle, and another warning device 100–500 feet behind your vehicle. This regulation also specifies where to place warning devices on other types of roadways such as divided highways and undivided two-way roads. These situations are also covered in the section on "Communicating Your Presence" in your state CDL manual.

Not quite. The answer is 8

Under the Hours of Service regulations, after you've driven for 8 cumulative hours without a break, you must take a 30-minute break. Note that time that you spend on duty but not driving can be counted as part of the break.

Source: "Summary of Hours of Service Regulations," FMCSA, https://www.fmcsa.dot.gov/regulations/hours-service/summary-hours-service-regulations

Not quite. The answer is Check the electrical connections.

If your trailer lights aren't working properly, the cause may be as simple as a loose electrical cable connection to the trailer, or perhaps to the tractor. Electrical connections can loosen over time from constant use. Wiggle each connector back and forth to see if it's loose. If it is, tie something around it to keep it from moving. If the connector isn't loose, check if the pins in the receptacle are clean and make good contact. Lastly, check if the cable itself is bad. If none of these are the cause of the problem, the next thing to check is the fuses or circuit breakers, and finally, the trailer light bulbs. Note: Don't ignore the problem. If any required trailer lights aren't working properly, your vehicle is in violation of federal regulation 49 CFR 393.23 and can be placed out of service at a roadside inspection.

Not quite. The answer is 12 feet

Each lane on an interstate highway is at least 12 feet (144 inches) wide. Note that under federal regulations, the maximum width of CMVs operated on interstate highways is 8½ feet or 102 inches (approximately 2.6 meters) except in Hawaii, where the maximum width is allowed to be 9 feet (108 inches).

Source: 23 CFR 658.15

Not quite. The answer is October 20, 1994

Under federal regulations, every CMV with air brakes that was manufactured since October 20, 1994, must have automatic slack adjusters. Antilock brakes (ABS) have been required on all buses with air brakes that were built since March 1, 1998. ABS has also been required on all tractors with air brakes that were built after March 1, 1997, and all trailers with air brakes that were built after March 1, 1998.

Source: 49 CFR § 393.53

Not quite. The answer is you will have more control over the vehicle than if the tractor lacked ABS.

Having ABS on only the tractor, only the trailer, or even only one axle, still gives you more control over the vehicle during braking than you would have without ABS at all. Brake normally. If only the tractor has ABS, you should be able to maintain steering control, and there is less chance of jackknifing. But keep your eye on the trailer and let up on the brakes (if you can safely do so) if it starts to swing out.

Not quite. The answer is Both of the above are correct.

When testing the service brakes, check the following: (1) whether the brake pedal holds up or sinks to the floor; (2) whether the vehicle seems to pull to one side; (3) whether it takes longer than it should to stop your vehicle; and (4) whether the brakes just "feel strange," based on your experience driving comparable CMVs. Any of these signs could indicate a problem with the brake system that should be corrected before you drive the vehicle.

Not quite. The answer is Stop driving as soon as you can safely do so.

When traveling on ice, your vehicle's braking distance can increase tremendously. On ice, slow down to a crawl and stop driving as soon as you can do so safely.

Not quite. The answer is Use the highest reverse gear.

Always back as slowly as possible. Use the lowest reverse gear. That way you can more easily correct any steering errors. You can also stop quickly if necessary.

Not quite. The answer is Both of the above

The most obvious sign of a tire blowout is a loud "bang," but there are other signs too. If the vehicle thumps or vibrates heavily, it may be a sign that one of the tires has gone flat. If the steering feels "heavy," one of the front (steering) tires may have failed.

Not quite. The answer is go straight ahead even if the steering wheel is turned.

In a front-wheel skid, the front end tends to go in a straight line regardless of how much you turn the steering wheel.