The Ultimate CDL General Knowledge Study Guide You’ll Ever Need

Getting your CDL starts with passing the general knowledge test, but studying can feel overwhelming. That’s why we’ve created this CDL general knowledge study guide—to simplify key concepts, provide essential test-taking strategies, and help you feel confident on exam day. Whether you’re a first-time applicant or refreshing your knowledge, this guide covers everything you need to know to pass with ease. Let’s get started!

What to study for the CDL general knowledge test?

It covers essential topics every truck or bus driver must know to operate safely and legally. The test includes multiple-choice questions based on information from your state’s CDL manual.

• Vehicle Inspection: Ensuring your vehicle is safe to drive.
• Basic Vehicle Control: Proper steering, braking, and maneuvering techniques.
• Communication: How to signal and interact with other road users.
• Safe Driving Practices – Speed management, following distances, night & bad weather driving, emergency maneuvers.
• Cargo & Securement – Weight distribution, load securement, and hazardous materials awareness.
• Hours of Service & Regulations – Driver fatigue rules, drug & alcohol policies, and accident reporting.
• Hazard Awareness: Identifying and responding to road hazards.
• Emergency Procedures: Steps to take in case of a breakdown or accident.

Now, let’s dive into a detailed study guide for each of these essential topics.

CDL General Knowledge study guide

Don’t just memorize—understand. Here’s how to master each section:

1. Vehicle Inspection

Conducting thorough vehicle inspections before and after trips ensures safety and compliance. Study these key areas to avoid missing key details.

7-Step Method for Pre-trip Checks

1. Comprehensive Exterior Check

• Walk around the vehicle to inspect its overall condition.
• Look for leaks, damaged components, or loose parts.
• Review the previous inspection report to ensure all issues were resolved.

2. Under-the-Hood Assessment

• Ensure the parking brakes are set before opening the hood.
• Check fluid levels, belts, hoses, and electrical connections.
• Look for leaks, cracks, or signs of wear in the engine compartment.

3. In-Cab Inspection and Engine Startup

• Verify the dashboard warning lights turn off as expected.
• Test the functionality of mirrors, windshield wipers, and horn.
• Ensure emergency equipment (fire extinguisher, warning triangles) is present.

4. Lighting and Indicator Verification

• Activate headlights, turn signals, and hazard flashers.
• Walk around the truck to confirm all lights are operational.
• Test the dimmer switch and brake lights.

5. Tire and Suspension System Check

• Inspect tire pressure, tread depth, and sidewall condition.
• Ensure lug nuts are tight and rims are damage-free.
• Examine the suspension for signs of wear or leaks.

6. Brake System and Underbody Review

• Test air or hydraulic brakes by pressing the pedal and checking for pressure loss.
• Inspect hoses, lines, and connections for leaks or damage.
• Confirm trailer connections and coupling components are secure.

7. Final Safety Checks Before Departure

• Ensure all cargo is properly secured and placards are correctly displayed (if hauling hazardous materials).
• Verify that the license plate and any required permits are in place.
• Secure all tools, hatches, and storage compartments.

During the Trip Inspection

• Inspect within the first 50 miles, then every 150 miles or every three hours.
• Monitor tire condition, brakes, air pressure, and cargo securement.

Post-Trip Inspection

• Look for leaks, damaged parts, and worn-out tires.
• Note any mechanical issues and report them immediately.

Study Tip: Use a checklist and physically practice the inspection process to reinforce your learning.

2. Basic Vehicle Control

Proper handling of a large vehicle requires skill and precision. Focus on:

• Steering & Lane Positioning – Keep the vehicle centered; avoid oversteering.
• Shifting Gears (if manual transmission) – Learn proper gear usage for different road conditions.
• Braking & Acceleration – Avoid sudden stops or rapid acceleration to maintain control.
• Backing Up & Parking – Use mirrors, go slow, and back to the driver’s side (left) for better visibility.
• G.O.A.L: Get Out And Look before backing up.

Study Tip: Watch instructional videos and practice backing maneuvers in a controlled environment.

3. Communication on the Road

Good communication prevents accidents and ensures safety:

• Using Turn Signals & Brake Lights: Always signal well in advance.
• Headlight Use: Use headlights in fog, rain, and low-light conditions.
• Horns & Hand Signals: Alert pedestrians and other drivers when necessary.

4. Safe Driving Practices

Good driving habits reduce risks and prevent accidents.

• Speed & Space Management
  • Follow the “one-second-per-10-feet” rule.
  • Adjust speed for road, weather, and traffic conditions.
• Night & Bad Weather Driving
  • Use low beams in fog, slow down, and increase following distance.
  • Adjust speed on wet roads to prevent hydroplaning.
• Emergency Maneuvers
  • Learn skid recovery techniques.
  • React properly to tire blowouts and brake failures.

Study Tip: Practice safe driving during training.

5. Cargo & Securement

Proper cargo handling prevents load shifts and accidents.

• Weight Distribution – Follow axle weight limits.
• Load Securement – Use straps, chains, and tarps correctly.
• Hazardous Materials (if applicable) – Understand basic regulations and safety measures.

6. Hours of Service & Regulations

Compliance with HOS rules and other CDL regulations ensures driver alertness and road safety.

• Driver Fatigue Rules – Observe mandatory break and shift limits.
• Drug & Alcohol Policies – The CDL BAC limit is 0.04%; violations lead to disqualification.
• Accident Reporting – Follow FMCSA and state procedures after an incident.
• Medical Requirements – Fulfill all requirements and get an approved Medical Examination Report – Medical Card.  

7. Hazard Awareness

Recognizing hazards early helps prevent accidents. Study:

• Work Zones: Slow down and watch for sudden stops.
• Pedestrian & Cyclist Awareness: Be extra cautious in urban areas.
• Weather-Related Hazards: Adjust driving habits in high winds, heavy rain, or snow.

Study Tip: Take practice tests focused on hazard awareness.

8. Emergency Procedures

Be prepared for unexpected breakdowns or failures. Learn:

• Tire Blowouts: Hold the steering wheel firmly and let the vehicle slow down gradually.
• Brake Failure: Downshift and use the emergency brake if necessary.
• Engine Overheating: Pull over, turn off the engine, and let it cool.

Study Tip: Memorize step-by-step procedures for common emergencies.

Additional Study Tips

• Create a Study Plan: 
  • Break down topics into manageable daily study sessions to avoid last-minute cramming.
  • Dedicate extra time to challenging sections such as air brakes, weight regulations, and vehicle inspections.
  • Set study goals and track your progress to ensure consistent improvement.
• Use Mnemonics & Visual Aids
  • Create memory aids for PSI ranges and safety procedures.
  • Watch YouTube videos and use diagrams to visualize complex systems.

• Master Key Safety Thresholds: Understanding essential safety limits is crucial for passing the test and real-world driving. Memorize the following:

• • Cut-out pressure: 120–125 psi
  • Low air warning activation: Below 60 psi
  • Spring brake activation: 20–45 psi
  • Max air leakage rate: 3 psi for single vehicles, 4 psi for combination vehicles

• Practice Inspection Procedures

• • Recite pre-trip inspection steps aloud.
  • Use flashcards to memorize different system checks.
  • Perform mock inspections on an actual vehicle if possible.
• Review State-Specific Laws: 
  • CDL regulations vary by state, so be sure to check your state’s CDL manual for any unique rules or requirements.
  • Some states may have stricter weight limits, medical requirements, or additional safety regulations to follow.
• Take Practice Questions and Test:
  • Simulate real test conditions with the full-length test to improve time management and tenure readiness before your actual exam.
  • Review incorrect answers to identify weak areas and focus on them in your study plan.

Take the free CDL general knowledge practice test now!

By following this guide, you’ll be well-prepared to pass your CDL General Knowledge Test with confidence!

FAQs

1. Does a CDL General Knowledge Study Guide include a practice test?

Yes, we offer a full-length practice test along with this CDL General Knowledge Study Guide to help you assess your knowledge and improve your test readiness. Our sample test closely mimics the real CDL general knowledge exam, following the structure and topics outlined in the official CDL manual. It includes multiple-choice questions covering essential areas like road safety, vehicle inspections, traffic laws, and hazard awareness.

Pro Tip: Taking a practice test under timed conditions helps you get comfortable with the actual exam format, improve time management, and reinforce key concepts through explanation-based answers.

2. Why is a CDL General Knowledge Study Guide important?

A CDL General Knowledge Study Guide is essential because it provides structured learning, essential safety guidelines, and practice materials to help you succeed. Here’s why it’s important:

• Covers Key Exam Topics – Ensures you understand critical subjects such as vehicle inspections, safe driving practices, cargo handling, and emergency procedures.
  
• Boosts Exam Confidence – Familiarizes you with the test format and question types, reducing anxiety on exam day.
  
• Enhances Road Safety – Teaches best practices for operating commercial vehicles, helping you become a responsible and skilled driver.
  
• Saves Study Time – Organizes information in a clear and concise way, allowing for more efficient learning.
  
• Includes Practice Questions and Sample Test – Provides real exam-style questions to reinforce knowledge and improve test performance.

Final thoughts

Preparing with a CDL General Knowledge Study Guide gives you the foundation needed to pass your test and become a safe, knowledgeable commercial driver. By following our study guides and taking our practice questions and sample test for CDL general knowledge, you can approach the exam with confidence. Good luck!