SCDMV Commercial Driver's License (CDL) Practice Test

These questions are part of the practice quiz. Start practicing

• Why is it important to recognize overloads in cargo?
• If you need to make a U-turn in a commercial vehicle, what should you consider first?
• What action should a driver take upon noticing bad road conditions while loaded?
• Is one broken or missing leaf of a spring sufficient to make the vehicle dangerous?
• Which windshield feature is crucial in winter conditions?
• What is the best way to regain control after skidding?
• What kind of vehicles requires a CDL to operate?
• Why is it critical to ensure cargo does not obscure your view?
• What could be a sign of trouble with the vehicle's suspension system?
• What is a hazardous materials placard?
• What is the main reason for using a reflective triangle on the road?
• Which statement is true about the actions taken when handling an emergency situation on the road?
• What minimum tread depth is required for other tires?
• What is an indication that a vehicle may have brake issues?
• What is considered the safest speed to maintain while driving with traffic?
• Why is it essential to understand load limits?
• If an oncoming driver drifts into your lane, what is the recommended action?
• What risk is associated with rough acceleration?
• What happens if one-fourth of a spring's leaves are broken or missing?
• What should a driver do if they notice a crack in the frame members during an inspection?
• What is the recommended maximum speed for a urinating drain during a long trip?
• What action should you take when driving at night?
• In what scenario should you downshift your vehicle?
• What should you do before leaving your vehicle unattended?
• Which of the following is NOT a critical item to check during a trip?
• Which statement best describes a potential risk of not properly covering cargo?
• When should you use your low beams while driving?
• What is crucial when operating a vehicle with a trailer?
• In cold weather, what should you ensure about your windshield wipers and washers?
• What is the purpose of a windshield wiper washer fluid in commercial vehicles?
• Which item is required during a pre-trip inspection?
• Which items should be inspected during the enroute inspection?
• What does "communicating" mean in safe driving?
• How often should you check your brake fluid level?
• What is a sign of a dangerous vehicle in terms of its springs?
• What is one common method of securing cargo in an open bed?
• What is the primary reason for using the engine brake on a truck?
• What does the acronym ELD stand for in commercial driving?
• What is the primary purpose of controlled braking?
• What is one common cause of truck accidents?
• When is it permissible to use a cell phone while operating a commercial vehicle?
• During a walk-around inspection, what should you check regarding the condition of the steering system?
• In the event of an emergency, what is your first priority?
• If involved in an accident, what information are you required to provide?
• What should you do before returning to the road if you leave it?
• Which type of lights must be functional on a commercial vehicle?
• What is a CDL holder's responsibility regarding vehicle maintenance?
• What is the first step you should take at an accident scene involving injuries?
• What does the "P" endorsement allow a CDL holder to do?
• What is the purpose of a tachometer in a vehicle?
• What issue can arise from missing or broken leaves in any leaf spring?
• In addition to protecting people, what is another reason for covering cargo on an open bed?
• In which conditions may legal maximum weights not be safe?
• How do the "N" and "H" endorsements differ?
• What is the maximum allowable degree of play in steering wheels?
• Why is wearing a seatbelt important for commercial drivers?
• What should you do if your load shifts while driving?
• What can happen if cargo is not secured properly during transport?
• What is a critical factor to consider with heavy vehicles when merging into traffic?
• What should you do when turning right from a two-lane street to another two-lane street?
• How can you prevent rollovers when making turns?
• How often should you check your tires in hot weather?
• Which items should be inspected under the hood before driving?
• What should a driver do if they feel drowsy while driving?
• When should turn signals be activated?
• In a front wheel skid, how does the vehicle typically behave?
• What is required for transporting hazardous materials with a CDL?
• When should you begin turning left from a two-lane street onto another two-lane street?
• How should you check the condition of the front axle during a walk-around inspection?
• What is the purpose of escape ramps on highways?
• What defines a "commercial driver's license"?
• What safety feature is vital for preventing a trailer from swaying?
• What is a crucial limitation of mirrors while driving?
• What is the minimum tread depth for front tires as required?
• What is the minimum number of tie-downs required for a flatbed load?
• What are some of the key parts involved in steering a vehicle?
• What is the appropriate following distance at speeds under 40 mph?
• What is an important factor to consider when loading a trailer?
• What is the maximum blood alcohol concentration (BAC) allowed for commercial drivers?
• What three kinds of emergency equipment must you have in your vehicle?
• Which responsibility do drivers have regarding cargo?
• What does it mean when a vehicle has a “Gross Vehicle Weight Rating” (GVWR)?
• What are the three types of vehicle inspections that a commercial driver must conduct?
• What is defensive driving?
• What is the recommended action when driving on slippery roads?
• What is the perception distance in the context of stopping distance?
• What should you never do with a hot radiator cap?
• What is the proper action if a pedestrian is in your path?
• If a tire blows out, what should you avoid doing until you have slowed down?
• If you leave the road, what is the best course of action before returning to the highway?
• What is the primary reason to use high beams only when safe?
• Which of the following is required emergency equipment for commercial vehicles?
• Why is it important to secure cargo properly?
• Why is it important to conduct a vehicle inspection?
• What is a “no-zone” in relation to large commercial vehicles?
• Which component is NOT part of the steering system?
• When setting out warning devices, where should they be placed in relation to the driver?
• What does a red triangle with an orange center signify?
• How can a driver avoid problems with wet brakes?
• What is the purpose of flashing brake lights in a commercial vehicle?
• What should be done if a vehicle has an unstable load?
• What is typically the cause of brake fade?
• When steering to avoid a crash, how much should you turn the wheel?
• If warning devices are not visible from 500 feet, what should the driver do?
• What happens if your wheels are skidding while braking?
• During a pre-trip inspection, which fluid levels should be checked?
• What should you avoid doing while driving a commercial vehicle?
• Which factor increases the required stopping distance for a vehicle?
• In an emergency situation, what is generally true regarding vehicle maneuvering?
• How can you identify if your vehicle is equipped with anti-lock brakes?
• Which type of cargo is NOT suitable for a flatbed truck?
• What does the "N" endorsement allow a driver to operate?
• What should newer trucks do when going down long downhill grades?
• When is it necessary to have your commercial vehicle inspected?
• What is the recommended braking technique when going down a steep downgrade?
• Should radial and bias ply tires be used on the same vehicle?
• When using a curved downhill exit ramp, when should you begin to slow down?
• What should you do when driving in work zones?
• What is the primary function of retarders in commercial vehicles?
• How often should pretrip inspections be conducted?
• For a 20-foot load, what factor determines the number of required tie-downs?
• What should you do if you are unable to steer the vehicle properly?
• What should you do if you experience a tire blowout while driving?
• What should you do if you see a school bus with its stop sign extended?
• What is the impact of under-inflated tires on vehicle safety?
• When is it appropriate to use high beams while driving?
• What must you always do before making a lane change in a commercial vehicle?
• What is a common safety feature in modern commercial vehicles?
• If you increase your speed, how much will your stopping distance increase?
• What does the term “jackknifing” refer to in commercial driving?
• What factors help determine a "safe" speed when descending a long, steep downgrade?
• Which of the following is one of the primary reasons for covering cargo on an open bed vehicle?
• Which defect can lead to suspension system failure?
• What is the difference between aggressive driving and road rage?
• What is counter steering?
• What type of vehicle requires a Class B CDL?
• Is it permissible to use mismatched tire sizes on the same vehicle?
• How frequently must drivers check their cargo while on the road?
• Why are mirrors essential on commercial vehicles?
• What is the safest way to handle a tire blowout in a commercial vehicle?
• What is the function of the clutch in a manual transmission truck?
• Under good conditions, how much space should a 40-foot vehicle maintain at 35 mph from the vehicle ahead?
• What is one of the consequences of not adhering to tie-down regulations for cargo?
• How long does it typically take for a tractor-trailer to clear a double track?
• What is the correct procedure to test hydraulic brakes for leaks?
• What is a key aspect of safe night driving?
• What should you do to minimize skidding on slippery roads?
• What is a potential consequence of over-accelerating while driving?
• What should be checked using mirrors when driving?
• What procedure should be followed when starting on an uphill grade?
• If you experience a tire blowout, what should you do?
• What must be done if a commercial driver receives a citation?
• What is one technique to help keep brakes dry when driving through standing water?
• How often should a driver check the tire pressure on a commercial vehicle?
• What is the significance of weight distribution in a commercial vehicle?
• What is the purpose of the vehicle identification number (VIN)?
• When driving in hot weather, what should you avoid?
• What should you do before entering a curve while driving?
• Which type of vehicle is likely to become stuck on a railroad-highway crossing?
• How can you ensure you maintain a safe following distance?
• What is the purpose of using a logbook in commercial driving?
• Why is it important to not exceed axle weight limits when transporting a load?
• Which of the following is a key responsibility of a commercial driver?
• Under what conditions can a vehicle skid?
• What is the minimum age requirement to apply for a Commercial Driver's License (CDL) in South Carolina?
• What should you do if the brake pedal goes to the floor with hydraulic brakes?
• What is an example of a Class A commercial vehicle?
• What should you ensure about your vehicle's four-way flashers during the inspection?
• When should you use turn signals in a commercial vehicle?
• What is a critical factor to check before a long trip with a commercial vehicle?
• What should you do when being tailgated?
• If a vehicle leaves the road, what should the driver try to do before returning to the highway?
• In what positions should your hands be placed on the steering wheel for optimal control?
• What safety consideration is involved in covering cargo during transport?
• What role does weather play in the necessity of cargo coverage?
• What is the purpose of a pre-trip inspection?
• What is the consequence of taking a drug or alcohol test and testing positive?
• What is the primary function of the air brake system in a commercial vehicle?
• Why is it important to allow extra space when following another vehicle?
• At what conditions does hydroplaning become more likely?
• How can you determine how many seconds of following distance you have?
• What must a CDL holder do if they receive a traffic violation?
• What is considered a hazard on the road?
• What is the benefit of using the correct braking technique on a downgrade?
• What should you do if the rear wheels slip during acceleration?
• How many total tie-downs should you use for a load longer than 20 feet?
• What is the safest way to back up a vehicle?
• What should be repaired before driving if leaks are identified?
• Which document should a driver verify before transporting a sealed load?
• How far ahead should a driver be looking while driving a commercial vehicle?
• What is one of the conditions to check for when inspecting your windshield?
• If there are two or more left turn lanes, which lane should you use?
• What should you do if your load shifts while traveling?
• What is required by the SCDMV for renewing a CDL?
• What document is necessary when operating a commercial vehicle transporting hazardous materials?
• Where should warning devices be placed on a four-lane divided highway?
• What is an important consideration when using the horn in a commercial vehicle?
• What type of fire cannot be extinguished with water?
• How should you position your hands on the steering wheel?
• What must a driver check before transporting a sealed load?
• How long is a CLP (Commercial Learner's Permit) valid in South Carolina?
• What are the consequences of not having the appropriate endorsements on your CDL?
• What is the minimum number of tie-downs required for secure transportation of a 20-foot load?
• What type of irregular tire conditions should be reported during inspections?
• When passing another vehicle, what should a driver assume about the other driver?
• What is an important consideration when entering or crossing traffic with a heavy vehicle?
• What is the purpose of a pre-trip inspection?
• In hot weather, what should you be extra careful about regarding vehicle maintenance?
• How many red reflective triangles should you carry in your vehicle?
• How much should you reduce your speed on wet roads?
• Where should you place reflectors when stopped on a divided highway?
• Which of the following is NOT a requirement for obtaining a CDL?
• What three components make up total stopping distance?
• What should a CDL driver do if they experience brake failure?
• What is a common sign of aggressive driving?
• What is the safe distance to use for merging onto a highway?
• Which technique can help prevent rolling back when starting on a hill?
• What should bearing seals be primarily checked for?
• Under what condition should headlights be turned on in a commercial vehicle?
• How does a vehicle's height change?
• What effects can wet brakes have on a vehicle?
• How far ahead should a driver look according to the manual?
• When should you downshift an automatic transmission vehicle?
• How does excessive weight on the front axle affect vehicle handling?
• What are two main things drivers should look for ahead?
• How should drivers use their senses during a trip?
• When descending downhill grades, how should you apply brake pressure?
• What should you do if you experience brake failure while driving a commercial vehicle?
• What is the correct technique for backing up a commercial vehicle?
• What should brake shoes or pads ideally be free from?
• What is the stopping distance required for a heavy vehicle moving at 55 mph on dry pavement?
• What should a driver be cautious about when using a retarder on slippery surfaces?
• What is the correct method to correct a drive wheel braking skid?
• When is it legal to use a cell phone while driving a commercial vehicle in South Carolina?