New Mexico · General Knowledge CDL Practice Test

Federal regulations require an in-route inspection within the first 50 miles of the trip and then every 150 miles or 3 hours, whichever comes first.

Pre-trip inspections exist to find safety defects before the vehicle moves. Equipment failures cause crashes, and the inspection is your first chance to catch them.

Tire inflation must be checked during pre-trip and during every in-route inspection. Underinflated tires overheat and can blow out.

Cracked or broken wheels and rims are a serious safety hazard and an out-of-service violation under federal regulations.

Federal regulation requires at least 4/32 inch of tread depth on steer tires; 2/32 inch on other tires.

You verify the oil level is safe to drive. Hot radiator caps must never be removed; doing so risks serious burns from pressurized coolant.

Backing has large blind spots directly behind the trailer. A helper standing where you can see them in the mirror dramatically reduces backing-related crashes.

Always back to the driver's side when you have a choice. You can see better and judge clearance more accurately.

Excessive speed for the conditions is the leading cause of skidding and hard-braking crashes. Adjust your speed for traffic, weather, and road surface.

After completing a turn, cancel the signal so you do not mislead other drivers about your intentions.

Proper gear selection keeps the engine in its safe RPM range and gives you adequate power for road conditions, especially on grades.

Retarders (engine, exhaust, hydraulic, or electric) reduce brake wear by absorbing energy. They should be turned off on slick roads to prevent skidding.

Pick a safe speed and a low enough gear to hold the vehicle there. The engine and gear do most of the work; the service brakes are used briefly and firmly when needed.

Quick, frequent mirror checks keep you aware of traffic without taking your eyes off the road for long.

You should always be able to stop within the distance illuminated by your headlights. If you can't see far, slow down.

Horns can startle others; use them only when needed to avoid a crash. Signaling intent and avoiding hazards is preferred.

A light tap activates brake lights without slowing the truck and is a recognized way to make your presence visible at night, especially when stopped or parked.

The federal rule of thumb is one second per ten feet of vehicle length, plus one second above 40 mph. Increase further in poor conditions.

Open more space in front so you have time to brake gently if needed, reducing the chance the tailgater will rear-end you.

If you cannot see the other driver's reflection in their mirrors, you are likely in their blind spot.

Empty trucks have less weight on the tires, less traction, and longer stopping distances. Loaded trucks actually stop better in many conditions because the weight presses the tires onto the road.

Total stopping distance is the sum of perception (seeing the hazard), reaction (moving foot to brake), and braking (vehicle slowing to stop) distances.

Braking distance increases with the square of speed. Double the speed produces roughly four times the braking distance.

In rain or on wet roads, slow to about one third less than your dry-road safe speed.

Packed snow requires roughly half your dry-road speed. Ice requires you to slow even more or stop entirely if possible.

Low pressure and worn tread both raise hydroplaning risk by reducing the tire's ability to channel water away from the contact patch.

Hazard awareness means scanning constantly for things that might become emergencies — pedestrians, parked cars, debris, weather, other drivers.

Cover the brake and slow. The driver may turn slowly or may turn into a driveway just before the intersection.

Impaired drivers commonly drift, brake erratically, react slowly, and make sudden lane changes. Increase distance from any vehicle showing these signs.

Hard braking after a blowout can cause loss of control. Hold the wheel firmly, ease off the accelerator, let the vehicle slow, then brake gently and pull off.

Locked wheels cannot steer. Release the brakes to restore steering, then steer in the direction you want the vehicle to go.

Controlled braking applies the maximum force just below the lock threshold and holds it. Use it when you must stop quickly without losing steering.

Stab braking is a manual approximation of ABS — full apply, release on lockup, reapply. It only works on vehicles WITHOUT ABS.

Federal regulation prohibits CMV drivers from texting while driving. Penalties include disqualification and substantial civil fines.

Hand-held mobile phone use is prohibited for CMV drivers under FMCSA regulations. Hands-free use is permitted with the device within reach.

De-escalate. Get out of the way, do not engage, do not provoke. If the situation is dangerous, call law enforcement.

For commercial vehicle operation, the federal DUI threshold is 0.04% blood alcohol concentration — half the standard non-commercial threshold of 0.08% in most states.

Refusal of testing is treated as a major offense — equivalent to a positive test — and triggers a one-year disqualification (three years if hazmat-placarded).

Protect the scene first — set out warning devices and direct traffic if needed — then attend to injured persons and notify authorities.

On a divided highway, place reflective triangles 10, 100, and 200 feet behind the vehicle, on the shoulder side.

10, 100, 200 feet to the rear is the standard placement on one-way or divided roadways.

Two-lane two-way roads require triangles at 10 feet behind, 100 feet behind, and 100 feet ahead so traffic from both directions sees the warning.

Tire fires require large amounts of water for cooling because the rubber retains heat and reignites. Class B extinguishers alone are inadequate.

Cut power if possible and use a CO2 or dry-chemical extinguisher. Water on a live electrical fire creates shock hazard.

Excess weight overloads brakes, tires, and suspension and lengthens stopping distance significantly.

Federal rules require that cargo not spill or fall from the vehicle. Tarping or covering loose loads (gravel, debris, etc.) is required by many states and by federal cargo securement rules.

You remain responsible for not exceeding gross or axle weight limits even with sealed loads, and you must check securement of the seal and exterior.

Fatigue degrades reaction time and judgment as much as alcohol impairment. Pull over, get sleep, or hand off the load.

Many prescription and over-the-counter drugs cause drowsiness or impaired judgment. Always check with the prescribing physician before driving commercially.

A leaking exhaust system can introduce carbon monoxide into the cab. Symptoms include headache, dizziness, and confusion — pull over and ventilate.

Map and screen reading takes your eyes off the road and is a recognized contributor to crashes. Pull over when you need to navigate.

A vehicle on the shoulder may be disabled or starting to move. Slow, change lanes if possible, and be ready for the unexpected.

Worn tread reduces traction in rain (hydroplaning), in snow, and during hard cornering or braking. Replace before tread depth drops below regulatory minimums.

Slow before the curve, then maintain a steady speed through it. Braking inside a curve shifts weight and reduces tire grip.

Posted limits assume ideal conditions. Slow to a speed safe for the actual road, weather, and traffic conditions, even when that speed is below the posted limit.

The 14-hour driving window cannot be reset by off-duty breaks within the day; only 10 consecutive hours off duty resets it.

A 30-minute break (off-duty or on-duty not driving) is required before driving past 8 cumulative hours since the last such break.

You can drive up to 11 hours after 10 consecutive hours off duty, within a 14-hour on-duty window.

A first DUI is a 1-year CDL disqualification, increased to 3 years if a hazmat placard was displayed at the time of the offense.

Second major offenses (DUI, refusal, leaving the scene, felony involving a CMV) result in lifetime disqualification, with reinstatement only after 10 years and rehabilitation.