CDL General Knowledge Test practice questions
237 free questions with answers and explanations.
- 151.A commercial driver is involved in a minor accident where there are no injuries and the vehicles are still operable. What is the driver's immediate priority after ensuring personal safety?Driving Safely
- 152.You are driving a commercial vehicle and must cross a set of railroad tracks. The crossing has a 'stop sign' but no flashing lights or gates. What is the correct procedure for crossing these tracks?Driving Safely
- 153.You are driving a commercial vehicle on a two-lane road and need to pass a slower vehicle. How much space should you ideally maintain between your vehicle and the vehicle you are passing before returning to your lane?Driving Safely
- 154.A commercial driver is preparing for a long trip and is checking the vehicle's electrical system. Which of the following is an indication of a potential problem with the alternator?Driving Safely
- 155.You are driving a commercial vehicle equipped with a manual transmission and need to downshift to maintain control on a downgrade. When should you complete your downshift?Driving Safely
- 156.You are preparing to restart your commercial vehicle after a brief stop in very icy conditions. The vehicle is equipped with a manual transmission. What is the best technique to minimize wheel spin and get moving safely?Driving Safely
- 157.A commercial driver is driving a vehicle equipped with a manual transmission. To prevent engine over-speeding and maintain control on a long, steep downgrade, what is the most effective technique?Driving Safely
- 158.You are driving a commercial vehicle and experience a sudden loss of air pressure in your air brake system while driving. What is the first and most critical action you should take?Driving Safely
- 159.You are driving a commercial vehicle and your front wheel suddenly leaves the paved surface and drops onto the shoulder. What is the safest immediate action to take?Driving Safely
- 160.When driving in heavy fog, which of the following lighting techniques is best for visibility and safety?Driving Safely
- 161.When driving a commercial vehicle, you notice a strong smell of burning rubber and see smoke coming from one of your dual tires. What is the most appropriate immediate action?Driving Safely
- 162.You are driving a commercial vehicle in very hot weather. What is a critical check you should make regularly to prevent engine failure?Driving Safely
- 163.You are driving a commercial vehicle and notice that the steering wheel has excessive play, meaning you can turn it several inches without the wheels reacting. What is the most likely cause of this issue?Driving Safely
- 164.You are preparing to drive a commercial vehicle equipped with air brakes. During your pre-trip inspection, you notice that the air pressure buildup time from 85 psi to 100 psi takes 60 seconds. What does this indicate?Driving Safely
- 165.A commercial driver is preparing to back their vehicle into a loading dock. What is the most effective and safest method to ensure the area behind the vehicle is clear?Driving Safely
- 166.A commercial driver notices that their vehicle's ABS malfunction light remains illuminated after the initial system check. What does this indicate, and what should be the driver's course of action?Driving Safely
- 167.A commercial driver notices that the vehicle's alternator warning light illuminates while driving. What does this typically indicate?Driving Safely
- 168.A commercial driver is operating a vehicle with a manual transmission on a long, steep downgrade. To effectively control their speed and prevent brake fade, what is the most appropriate action?Driving Safely
- 169.A commercial driver is driving a vehicle equipped with hydraulic brakes and notices that the brake pedal feels 'spongy' or goes nearly to the floor before engaging. What is the most likely cause of this symptom?Driving Safely
- 170.You are driving a commercial vehicle and must make an emergency stop on a wet road. Which braking technique is generally recommended for vehicles without anti-lock brakes (ABS)?Driving Safely
- 171.A commercial driver is preparing to operate a vehicle equipped with hydraulic brakes. When checking the brake system, the driver notices that the brake pedal goes to the floor with little resistance. What is the most likely cause of this issue?Driving Safely
- 172.When performing a pre-trip inspection, you notice that your vehicle's air compressor is not building pressure within the specified time. What is the minimum air pressure required for the air compressor to cut out?Driving Safely
- 173.You are driving a commercial vehicle in very hot weather. Which of the following is the most critical check to perform on your tires?Driving Safely
- 174.You are driving a commercial vehicle and notice that your steering feels loose and has excessive play, requiring constant small corrections to stay in a straight line. Which of the following is the most likely underlying cause?Driving Safely
- 175.You are driving a commercial vehicle equipped with air brakes. You notice that the air pressure gauge is showing a rapid drop in pressure while driving. What is the most immediate and critical action you should take?Driving Safely
- 176.A commercial driver is operating a vehicle with air brakes. While performing an air loss test, they notice that with the engine off and the service brakes applied, the air pressure drops more than 4 psi in one minute (for a single vehicle). What does this indicate?Driving Safely
- 177.You are driving a heavy commercial vehicle down a long, steep downgrade. Which of the following is the most effective braking technique to maintain a safe speed and prevent brake fade?Driving Safely
- 178.You are driving a commercial vehicle and must make a right turn at an intersection. What is the most critical factor to consider regarding your turning approach?Driving Safely
- 179.A commercial driver is attempting to recover from a skid where the drive wheels have lost traction. What is the most critical immediate action the driver should take?Driving Safely
- 180.When performing a pre-trip inspection, a commercial driver notices that the slack adjusters on a pushrod-type brake are not properly adjusted. What is the maximum allowable play (free travel) for a manual slack adjuster when the brakes are disengaged?Driving Safely
- 181.You are driving a commercial vehicle on a multi-lane highway. To maximize your visibility to other drivers, particularly passenger vehicles, where should you position your vehicle?Driving Safely
- 182.A commercial driver is preparing to drive a vehicle equipped with a manual transmission on a long, steep downgrade. To maximize control and prevent service brake overheating, what is the correct downshifting technique?Driving Safely
- 183.A commercial driver is preparing for a long haul through an area known for strong crosswinds. Which of the following precautions is MOST critical for maintaining control of the vehicle?Driving Safely
- 184.You are driving a commercial vehicle at night and another vehicle is approaching from the opposite direction. When should you dim your high beams?Driving Safely
- 185.You are driving a commercial vehicle on a two-lane road and are approaching a curve. To maintain control and safely navigate the curve, when should you apply your brakes?Driving Safely
- 186.A commercial driver is conducting a pre-trip inspection of their vehicle. Which of the following conditions, if found on a tire, would immediately disqualify the vehicle from operation?Driving Safely
- 187.A commercial driver is conducting a pre-trip inspection of their air brake system. They notice that the air pressure gauge shows a steady reading of 80 psi, and the low air pressure warning light and buzzer are activated. What is the most immediate action the driver should take?Driving Safely
- 188.A driver is preparing to descend a long, steep grade. They are operating a vehicle equipped with air brakes. Which of the following braking techniques should be used to maintain a safe speed and prevent brake fade?Air Brakes (if applicable)
- 189.A driver notices that the brake pedal on their air brake equipped vehicle feels 'spongy' or has excessive travel before the brakes engage properly. They also observe inconsistent braking performance. Which of the following is the most probable cause?Air Brakes (if applicable)
- 190.A driver is operating a vehicle with a dual air brake system. The air pressure gauge for the primary system indicates 65 psi, while the secondary system indicates 120 psi. What action should the driver take immediately?Air Brakes (if applicable)
- 191.A driver hears a loud 'whoosh' sound from the air brake system every few minutes. The air pressure gauge remains stable within the normal operating range. What does this sound most likely indicate?Air Brakes (if applicable)
- 192.During a pre-trip inspection, a driver notices that the air tank drains are clogged with sludge and ice. What is the primary risk associated with this condition?Air Brakes (if applicable)
- 193.A driver is inspecting the air lines of their commercial vehicle. They discover a section of an air line that is chafed and showing exposed fabric. What immediate action should the driver take?Air Brakes (if applicable)
- 194.A technician is troubleshooting a dual air brake system where the primary (rear axle) air tank pressure consistently drops faster than the secondary (front axle) air tank pressure during a static leakage test. What is the most likely area to investigate first?Air Brakes (if applicable)
- 195.A driver notices that the low air pressure warning light and buzzer activate when the air pressure drops to 70 psi. What action should the driver take immediately?Air Brakes (if applicable)
- 196.What is the primary purpose of the safety relief valve in an air brake system?Air Brakes (if applicable)
- 197.After stopping, a driver hears a continuous hissing sound from the general area of the air tanks. The air pressure gauge shows a slow but steady drop in pressure. What is the most likely cause?Air Brakes (if applicable)
- 198.When operating a vehicle with a dual air brake system, what is the primary reason for a driver to ensure that both the primary and secondary air tanks are at their full operating pressure before driving?Air Brakes (if applicable)
- 199.A driver is performing a pre-trip inspection. When checking the slack adjusters on the S-cam air brakes, they measure the pushrod travel. What is the maximum allowable pushrod travel for most commercial vehicles before adjustment is required?Air Brakes (if applicable)
- 200.A driver is performing a pre-trip inspection on a vehicle equipped with air brakes. They notice that when the brake pedal is fully depressed, the air pressure gauge drops from 120 psi to 80 psi. What is the most likely cause of this significant pressure drop?Air Brakes (if applicable)