Class B

CDL Class B Practice Test

Practice CDL Class B questions and answers for heavy single vehicles, inspection, air brakes, passenger vehicles, and safe driving decisions.

Last updated: June 26, 2026

Where this page fits

Core CDL knowledge: CDL Class B Practice Test

This page is one checkpoint inside the CDL study guide. Use the map to move between the full outline, topic notes, practice questions, and focused weak-area review.

Choose topics by vehicle and endorsement path.
Keep inspection and safe driving as the base.
Add passenger, school bus, tank, or air brake review only when needed.

CDL path and endorsements Start with license class, endorsement needs, state handbook checks, and the study order that fits your vehicle path. Commercial driver's license guide Connect the full phrase commercial driver's license to CDL meaning, license classes, permit practice, medical context, and state steps. Commercial vs non-commercial license Compare commercial and regular license assumptions, non-commercial wording, and when CDL study applies. Medical card and self-certification Understand medical examiner certificate context, CDL self-certification, state record updates, and official-source checks. CDL permit practice Use this first-step page for commercial learner permit study, state source checks, and the core CDL topics to practice before endorsements.

What to study for a CDL Class B path

A Class B path usually focuses on heavy single vehicles, but the exact study plan depends on the vehicle and endorsements. Start with general knowledge, then add air brakes, passenger, school bus, tank, or skills-test topics when they apply.

General knowledge, inspection, speed, space, and hazard response
Air brake systems when the vehicle uses air brakes
Passenger or school bus topics when the job path involves riders or students
Tank vehicle topics when the vehicle or load requires that endorsement
Basic control and on-road habits for a large single vehicle

How to study this topic

CDL Class B questions and answers: what to expect

Class B practice usually mixes general knowledge, vehicle inspection, speed and space judgment, and endorsement topics only when your vehicle path needs them. Questions rarely stay abstract: they change the road condition, passenger load, brake system, or vehicle size and ask what the driver should do next. Read each Class B question for the vehicle type before choosing an answer.

Sample Class B question types

Typical Class B sets include inspection defects (unsafe tire wear, low air pressure warning, missing emergency equipment), large-vehicle control (longer stopping distance, wider turns, mirror use), and endorsement scenarios such as passenger boarding, school bus stops, or tank surge when those endorsements apply. If your misses cluster around one type, switch to that focused study page instead of repeating a general Class B mix.

Match study topics to the vehicle

Class B does not mean every endorsement applies. Choose passenger, school bus, tank, or air brake review only when that vehicle path requires it.

Inspection still drives the study plan

Heavy single vehicles still need careful checks of brakes, tires, lights, steering, suspension, emergency equipment, leaks, and driver visibility before movement.

Practice judgment, not only facts

Class B questions often ask what the driver should do when visibility, stopping distance, passenger safety, or vehicle condition changes.

Class B and Class A are different because the vehicle is different

Class B study should stay centered on heavy single vehicles. Start with general CDL knowledge, then add air brakes, passenger, school bus, tank, or skills-test topics only when the vehicle path requires them.

Quick answers

Answers before you practice.

Short answers for the common CDL questions on this topic.

What is on a CDL Class B practice test?

A Class B study set should cover general knowledge, vehicle inspection, speed and space decisions, air brakes when applicable, and the endorsement topics required for the vehicle or job.

Study general knowledge

Do Class B drivers need passenger or school bus topics?

Only study passenger or school bus material when your vehicle path requires those endorsements. A straight truck, bus, tank vehicle, and school bus can create very different Class B study plans.

Review passenger topics

Is Class B easier than Class A?

Class B usually has less combination-vehicle content, but it still tests inspection, braking, large-vehicle control, road judgment, and any required endorsements. Easier depends on the vehicle and your weak areas.

Review inspection topics

What should I study first for Class B?

Start with general knowledge and vehicle inspection. Then add air brakes, passenger, school bus, tank, or skills-test practice only when those topics match the vehicle you will train or test with.

Start general knowledge practice

What is a Class B CDL?

Class B is the CDL path for heavy single vehicles and some buses or trucks depending on the exact setup. Check the vehicle configuration and state rules before assuming a class.

Review Class B study path

How do I get a Class B CDL?

Use the same CDL path as other classes: verify state requirements, study general knowledge, add the required vehicle topics, complete any permit or training steps, and then pass the tests tied to that vehicle path.

Read the CDL path

What to study for a Class B CDL permit?

Begin with general knowledge and inspection, then add air brakes if required, passenger or school bus topics if the vehicle needs them, and tank or skills-test practice only when relevant.

Practice questions

CDL Class B Practice Test Quiz

Answered 0 / 20

Question 1

When backing a commercial vehicle, which of the following is the most important safety rule?

Always back toward the right side so you can see better in the right mirror. Use a helper whenever possible and agree on a clear hand signal for 'stop'. Accelerate quickly to minimize the time spent backing. Only check your mirrors when you are turning the steering wheel.

Question 2

How far ahead should you be looking while driving a commercial vehicle at highway speeds?

1 to 2 seconds (about half a block). 4 to 6 seconds (about one block). 12 to 15 seconds (about a quarter of a mile). As far as the horizon allows.

Question 3

What is the minimum tread depth required for the front steering tires of a commercial vehicle?

2/32 inch 4/32 inch 1/16 inch 1/4 inch

Question 4

When is it appropriate to use your high beams?

Whenever you are on an unlit road, as long as it is safe and legal, and you dim them when within 500 feet of an oncoming vehicle. Only when driving outside of city limits. During fog or heavy rain to improve visibility. Whenever you are traveling faster than 55 mph.

Question 5

What is 'hydroplaning'?

When your tires lose contact with the road and ride on a thin film of water. When a vehicle drifts out of its lane due to strong crosswinds. A technique for saving fuel by coasting downhill. When air gets trapped in the hydraulic brake system.

Question 6

If you experience a tire blowout while driving at highway speeds, what is the FIRST thing you should do?

Brake hard to stop the vehicle quickly. Grip the steering wheel firmly and stay off the brakes until the vehicle slows down. Steer sharply onto the shoulder. Downshift immediately.

Question 7

What is the purpose of a pre-trip inspection?

Pre-trip inspection diagram showing engine, brakes, lights, tires, and coupling zones. — Pre-trip inspection zones

To ensure you have enough fuel for the entire journey. To find safety defects that could cause a breakdown or crash before you hit the road. To verify your electronic logging device (ELD) is connected. To satisfy weigh station requirements.

Question 8

What is the recommended following distance for a heavy vehicle traveling at 55 mph in ideal conditions?

CDL stopping distance chart showing perception, reaction, and braking distance. — Stopping distance includes perception, reaction, and braking time.

One second for every 10 feet of vehicle length, plus one extra second for traveling over 40 mph. Three seconds total, regardless of vehicle length. One car length for every 10 mph of speed. Five seconds total.

Question 9

What should you do if you are being tailgated?

Tap your brakes lightly to flash your brake lights and warn the tailgater. Speed up to increase the distance between you. Increase your following distance ahead of you to avoid sudden stops. Swerve slightly to scare them into backing off.

Question 10

When approaching a curve, what is the best way to handle your speed?

Maintain your speed and brake sharply as you enter the curve. Accelerate gently before entering the curve. Slow down to a safe speed before entering the curve, then accelerate slightly through it. Coast through the curve in neutral.

Question 11

What is the most common cause of serious vehicle skids?

Driving too fast for road conditions. Over-inflated tires. Using the wrong gear on a flat road. Faulty power steering.

Question 12

When driving a commercial vehicle, how should you adjust your speed for driving at night?

Drive faster to stay alert. Drive slow enough to stop within the distance you can see with your headlights. Keep the same speed as daytime as long as you have high beams on. Always drive 10 mph under the speed limit.

Question 13

What is the most important reason for inspecting your vehicle?

To avoid being fined at weigh stations. Safety for yourself and for other road users. To ensure your cargo arrives on time. To keep the vehicle looking clean.

Question 14

When should you check your mirrors while driving?

Regularly, as part of your scanning routine (every 5-8 seconds). Only when changing lanes. Only when backing up. Whenever you see a police car.

Question 15

What is the primary cause of fatal crashes involving commercial vehicles?

Equipment failure. Bad weather. Driving too fast. Poor road maintenance.

Question 16

If you are driving a 60-foot truck at 50 mph, what is the minimum following distance you should maintain?

4 seconds. 5 seconds. 6 seconds. 7 seconds.

Question 17

What should you do if an aggressive driver is harassing you?

Brake check them to back them off. Make every attempt to get out of their way and avoid eye contact. Match their speed and do not let them pass. Use hand gestures to signal your frustration.

Question 18

What is the best way to use the brake pedal on a steep downgrade?

Light, continuous pressure (riding the brakes). Apply firmly until you reach 5 mph below your safe speed, then release. Pump the brakes rapidly. Do not use the brakes; rely solely on the engine brake.

Question 19

When backing, why should you back toward the driver's side whenever possible?

It uses less fuel. It allows you to look out the side window and see the rear of your vehicle better. It prevents the trailer from swinging. The mirrors on the driver's side are larger.

Question 20

How can you tell if the road is becoming slippery due to dropping temperatures?

The exhaust becomes white. Ice will form on the mirrors and antenna first. The tires will make a louder humming noise. The steering wheel will shake.

Keep practicing

Choose what to practice next.

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