Texas General Knowledge CDL Practice Test

This is a free 20-question practice test for the General Knowledge portion of the Texas Commercial Driver's License knowledge exam. Questions are pulled from a pool of 97 drawn from the AAMVA CDL Manual, which is the source document the Texas Department of Public Safety Driver License Division uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Texas.

Question 1 of 20

When approaching a railroad crossing, drivers of buses, school buses, and placarded hazmat vehicles must:

Speed up to clear quickly
Stop between 15 and 50 feet from the nearest rail and listen
Cross only if a train is in sight
Sound the horn

Correct. Buses, school buses, and placarded hazmat vehicles must stop at every crossing, 15 to 50 feet from the nearest rail. Look and listen, then proceed when safe.

Question 2 of 20

A vehicle's "no zone":

Refers to the lane next to the cab
Includes the front, sides, and rear blind spots where other vehicles disappear from view
Is the area in front of the truck only
Does not exist for cars

Correct. The "no zone" is the set of blind spots around a truck — front, both sides (especially right), and rear — where other vehicles cannot be seen.

Question 3 of 20

Cargo that is loaded too high:

Has no effect on driving
Raises the center of gravity, increasing rollover risk
Improves fuel economy
Improves braking

Correct. A high center of gravity makes the vehicle prone to rollover on curves, ramps, and during evasive maneuvers. Stack heavier items low.

Question 4 of 20

If your vehicle hydroplanes, what should you do?

Brake hard immediately
Steer sharply to recover
Release the accelerator and push in the clutch
Accelerate to push through

Correct. Release the accelerator and push in the clutch. Do not brake or steer hard until the tires regain contact.

Question 5 of 20

When you arrive at a customer to deliver:

Just open the trailer
Sign in, follow site safety rules (PPE, speed limits, designated routes)
Skip site rules
Park anywhere

Correct. Customer sites have their own safety rules — sign in, wear required PPE, follow speed limits and designated routes.

Question 6 of 20

A fully loaded tractor-trailer traveling at 55 mph on dry pavement requires roughly what total stopping distance (perception + reaction + braking)?

100 feet
200 feet
300 feet (about the length of a football field)
600 feet

Correct. Total stopping distance for a heavy commercial vehicle at 55 mph on dry pavement is approximately 300 feet, or the length of a football field including end zones.

Question 7 of 20

To recover from a drive-wheel skid, you should:

Brake harder to slow down
Steer in the opposite direction of the skid
Stop accelerating, push in the clutch, and counter-steer
Apply the parking brake

Correct. Stop applying power, push in the clutch (or shift to neutral) to let the wheels turn freely, and counter-steer in the direction you want the front of the vehicle to go.

Question 8 of 20

Which of the following is NOT part of the seven-step pre-trip inspection method?

Approach the vehicle and overview
Check the engine compartment
Test the AM/FM radio
Walk around inspection

Correct. The radio is not part of the safety inspection. The seven-step method covers approach, engine compartment, in-cab checks, lights, walk-around, signal lights, and brake checks.

Question 9 of 20

When the brake pedal feels spongy on an air-brake vehicle:

It is normal
Stop and have the system checked — there may be air in the system or another issue
Drive faster
Pump the brakes harder

Correct. A spongy or unusual feel in air-brake pedals indicates a system issue. Have it inspected before continuing.

Question 10 of 20

What is "black ice"?

Ice that has been salted
A thin layer of ice clear enough that you can see the road through it
Ice on a black-painted road
Ice formed under the truck

Correct. Black ice is a thin, clear sheet of ice that looks like wet pavement. Suspect it whenever the temperature is at or below freezing and the road appears wet.

Question 11 of 20

Hazardous materials awareness is required for:

Only Hazmat-endorsed drivers
Every CDL holder, even without an H endorsement
Only owners
Only mechanics

Correct. Every CDL applicant must understand basic hazmat awareness — recognizing placards, labels, and shipping papers — even if they never haul hazmat.

Question 12 of 20

You are driving on a wet road. To test how slippery the road is, you can:

Brake hard at 50 mph
Accelerate hard and listen for tire spin
Gently apply the brakes at low speed
Look at other vehicles' tires

Correct. At low speed and in a safe place, you can gently test traction by lightly applying the brakes or by gently accelerating. Hard braking at high speed is dangerous.

Question 13 of 20

You are about to begin a trip and notice the dashboard low-air warning is on. You should:

Drive immediately
Wait for the air pressure to build above 60 psi (warning off) and complete the air-system pre-trip
Pump the brakes
Disconnect the warning

Correct. Allow pressure to build, the warning to clear, and complete the seven-step air-brake check before driving.

Question 14 of 20

When driving down a long, steep downgrade, you should:

Hold the brakes lightly the whole way down
Select the proper gear before starting down and use intermittent firm brake applications
Coast in neutral
Use only the engine brake

Correct. Select a low gear before starting down. Use the brakes in firm, intermittent applications: brake until 5 mph below safe speed, release until safe speed is regained, repeat. Continuous brake application overheats the brakes.

Question 15 of 20

Communicating your intention to other drivers is best accomplished by:

Honking the horn
Using turn signals well in advance
Flashing high beams
Pointing

Correct. Use turn signals well before turning or changing lanes. Brake lights, four-way flashers, and headlights also help communicate.

Question 16 of 20

Which of these is the best way to communicate that you are slowing down?

Tap the brake pedal a few times to flash the brake lights
Use the horn
Put on the parking brake
Wave at drivers behind

Correct. Lightly tapping the brake pedal flashes the brake lights, alerting drivers behind that you are slowing.

Question 17 of 20

Maximum allowable steering-wheel play is approximately:

5 degrees
10 degrees
20 degrees
30 degrees

Correct. Steering wheel play should not exceed 10 degrees (roughly 2 inches on a 20-inch wheel). More than that, the vehicle is hard to steer.

Question 18 of 20

When a vehicle ahead of you brakes hard, you should:

Brake harder
Apply the brakes immediately, even if you don't need to
Look for a way to steer around the vehicle if necessary, while preparing to brake
Honk to warn the driver behind you

Correct. Plan your escape: identify a clear lane or shoulder. If you can steer to safety, you save reaction time. If not, brake firmly without locking the wheels.

Question 19 of 20

Which of the following is true about driving at night?

Headlights illuminate further than you can stop within
You should drive faster to keep up with traffic
You should drive at a speed that lets you stop within the distance illuminated by your headlights
You can rely on oncoming headlights to help you see

Correct. Drive at a speed where your stopping distance does not exceed the distance you can see — typically 250 feet on low beams, 350-500 feet on high beams.

Question 20 of 20

When backing into a tight space, the driver should:

Get out and look (G.O.A.L.) before and during the maneuver
Trust the mirrors only
Back at full speed
Skip the helper

Correct. G.O.A.L. — Get Out And Look — is the universal driver-school rule. When in doubt, stop and look. Use a helper when available.

About the Texas General Knowledge exam

Most state DMVs administer 50 General Knowledge questions and require 80% (40 correct) to pass. Questions are pulled from a much larger pool, so two applicants taking the test on the same day will see different mixes. The questions on this site are drawn from the AAMVA CDL Manual chapters that every state's exam is built from.

The Texas Department of Public Safety Driver License Division follows the federal CDL standards established by FMCSA. To earn the General Knowledge credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full General Knowledge question bank or browse all Texas CDL practice tests.