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California CDL General Knowledge Practice Test

Selected knowledge practice, not a complete licensing course or practical training.

California CDL General Knowledge

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Question 1 of 150
  1. 1. Who is ultimately responsible for the safe operation of a commercial vehicle after an inspection?
  2. 2. Which items should a commercial driver monitor during a trip for signs of trouble?
  3. 3. What minimum tread depth is required in every major groove of a commercial vehicle’s front tires?
  4. 4. Which tire placement is prohibited on the front wheels of a bus?
  5. 5. What can rust around a commercial vehicle’s wheel nuts indicate?
  6. 6. Why is excessive steering-wheel play a serious inspection defect?
  7. 7. Which warning equipment is a standard option for a parked commercial vehicle?
  8. 8. During the CDL vehicle inspection test, what must an applicant do when identifying an item?
  9. 9. What is the principal method for controlling speed on a long downgrade?
  10. 10. When should a commercial driver select the proper low gear for a downgrade?
  11. 11. How should speed be chosen when fog or darkness limits the view ahead?
  12. 12. Under the handbook length rule below 40 mph, what is the minimum following time for a 50-foot commercial vehicle?
  13. 13. What extra following time should be added when traveling above 40 mph?
  14. 14. How should a commercial driver respond to a vehicle following too closely?
  15. 15. Why might an empty cargo van require more overhead clearance than the same van when loaded?
  16. 16. When a large vehicle needs extra room to complete a right turn, what should the driver avoid doing at the start?
  17. 17. Who is responsible for recognizing an overload or poorly balanced cargo?
  18. 18. For an accessible, unsealed truck load, when must the driver first recheck cargo securement after starting the trip?
  19. 19. After the initial check of an accessible, unsealed truck load, when is the next cargo reinspection required?
  20. 20. What does Gross Vehicle Weight describe?
  21. 21. Where should the heaviest cargo generally be placed to reduce rollover risk?
  22. 22. What can result from placing too little weight on the front axle?
  23. 23. What aggregate working load limit must a cargo securement system provide?
  24. 24. Under the general federal tie-down rule, a 7-foot article is not blocked against forward movement. What is the minimum number of tie-downs?
  25. 25. Why should a driver check cargo covers in the mirrors while traveling?
  26. 26. You must back into an unfamiliar loading space. What should you do before beginning the maneuver?
  27. 27. While backing slowly, you become unsure whether the right rear corner will clear an obstacle. What is the safest next step?
  28. 28. Your trailer is moving off the intended backing path and repeated small corrections are not restoring its position. What should you do?
  29. 29. The drive wheels begin spinning as you accelerate from a stop on a snowy road. What response does the handbook recommend?
  30. 30. You are approaching a curve in a commercial vehicle with a manual transmission. When should you reduce speed and select the appropriate lower gear?
  31. 31. A vehicle appears small and distant in your convex mirror. What should you remember before judging the available gap?
  32. 32. Before a trip with a trailer, which position allows an accurate check of mirror adjustment?
  33. 33. You are looking 12 to 15 seconds ahead as recommended for commercial driving. How should you also monitor the nearer road?
  34. 34. What is the safest way to make routine mirror checks while traveling?
  35. 35. Before departure, why should you secure loose tools and other articles in the cab?
  36. 36. A following driver wants to pass your truck. Should you wave them around as a guarantee that the road is clear?
  37. 37. Your commercial vehicle must stop on the highway shoulder. How soon must required emergency warning devices be placed?
  38. 38. On a straight divided highway with a clear view, what spacing does the handbook give for the three warning devices behind a stopped truck?
  39. 39. A truck stops beside a straight two-way road with clear sightlines. Why are warning devices needed both ahead and behind?
  40. 40. At dusk in rain, are identification and clearance lights alone sufficient to make your truck visible?
  41. 41. You keep your hands on the wheel but become absorbed in a stressful conversation. What type of distraction can this create?
  42. 42. When is the best time to program the route into your navigation system?
  43. 43. A car ahead drifts within its lane while its driver looks down repeatedly. How should you react?
  44. 44. An aggressive driver tries to provoke you. What is the safer response?
  45. 45. Snow covers the truck’s mirrors and side windows before departure. What is required for a safe start?
  46. 46. Why is a leaking exhaust especially dangerous when the cab windows are closed?
  47. 47. After water enters a truck’s brakes, what behavior can occur?
  48. 48. A properly inflated tire’s pressure rises during hot-weather operation. Should you bleed air to its cold-pressure reading?
  49. 49. During a hot-weather stop, a tire is too hot to touch. What does the handbook direct you to do?
  50. 50. When is it safe to open the pressurized radiator system for a coolant check?
  51. 51. Dark patches of tar have risen to the road surface in extreme heat. What hazard should you expect?
  52. 52. How should a manual-transmission truck cross railroad tracks?
  53. 53. One train has passed a crossing with two tracks. What must you check before proceeding?
  54. 54. A railroad crossing has no active lights or gates. What does that mean for your decision?
  55. 55. Why is listening for a horn alone an unsafe crossing check?
  56. 56. The front wheels slide and the truck continues straight despite steering input. What should you avoid?
  57. 57. Excessive braking has locked the rear drive wheels of a truck without effective ABS intervention. What is the first recovery action?
  58. 58. After a collision, you are uninjured and able to act. What is an immediate priority?
  59. 59. You stop to help at a collision in which your truck was not involved. Where should you park?
  60. 60. Smoke indicates a vehicle fire while you are driving. Where should you stop if you can safely move off the road?
  61. 61. Why should you avoid opening the hood fully during an engine fire?
  62. 62. Smoke comes from a closed box trailer, and the cargo may be hazardous. Should you open its doors to investigate?
  63. 63. For a small fire you can safely tackle with the correct extinguisher and an escape path, where should you aim?
  64. 64. You do not know which extinguishing agent is safe for the burning cargo. What should you do?
  65. 65. A B:C extinguisher is intended for which hazards?
  66. 66. What is the purpose of blocks secured snugly around cargo?
  67. 67. What does bracing between upper cargo and the compartment structure help prevent?
  68. 68. Why inspect a front-end header board before carrying a load?
  69. 69. You are ordered not to open a sealed load. Which duty still remains?
  70. 70. What makes a dry-bulk tank load demanding in a sharp curve?
  71. 71. Why is suspended meat cargo a special concern on an off-ramp?
  72. 72. How can live animals affect trailer stability?
  73. 73. Before taking an oversize or overweight load on California roads, what should you determine?
  74. 74. What does axle weight measure?
  75. 75. Your load is within the legal maximum. Does that guarantee it is safe for bad weather or a mountain route?
  76. 76. How should you determine suitable shift points for an unfamiliar commercial vehicle?
  77. 77. Why does the handbook advise turning a retarder off on a slippery road?
  78. 78. An approaching driver leaves bright lights on. What should you do?
  79. 79. Why clean both sides of the windshield before a night trip?
  80. 80. Your eyelids are heavy and you are struggling to stay alert. What is the safe response?
  81. 81. You see dense fog ahead while approaching a safe truck stop. What is the preferable choice?
  82. 82. Why should you avoid using another vehicle’s taillights as your only guide through fog?
  83. 83. When should you learn how to fit the chains carried for your drive tires?
  84. 84. Which combination matters when selecting a safe descent speed?
  85. 85. Your truck’s brakes have failed on a downgrade and an escape ramp is available. What should you do?
  86. 86. A hydraulic service-brake pedal goes to the floor. Which action may briefly restore hydraulic pressure?
  87. 87. A truck tire fails, but there is no immediate collision ahead. What is the initial response?
  88. 88. Does buying a cold medicine without a prescription prove it is safe before commercial driving?
  89. 89. You become too ill to operate your truck safely. What should you do?
  90. 90. Why must a commercial driver keep hazardous-material shipping papers readily accessible?
  91. 91. Who must supervise your public-road driving with a CLP?
  92. 92. What minimum initial CLP holding period applies before a CDL skills test?
  93. 93. Does a CLP replace the need for a valid underlying driver’s license?
  94. 94. A first-time Class A applicant in 2026 has no training exemption. Does self-study alone satisfy ELDT?
  95. 95. A Class B holder now seeks Class A with no exemption. Is the upgrade among the ELDT-covered applications?
  96. 96. A driver received Class A before February 7, 2022. Is ELDT automatically required again solely because that existing qualification predates the rule?
  97. 97. Without an applicable waiver, what minimum behind-the-wheel training does California require for an original Class A or B CDL?
  98. 98. For California interstate NI drivers in September 2026, who submits medical exam information through the National Registry?
  99. 99. Your Clearinghouse status is prohibited, but your CDL card has not expired. May you operate a CMV?
  100. 100. Which set describes the CDL skills assessment?
  101. 101. A car near an exit brakes repeatedly and drifts toward the through lane. What should you do before it becomes an emergency?
  102. 102. A temporary work lane is narrower than the normal lane. What demands extra attention from a truck driver?
  103. 103. Why can a sharp pavement-edge drop-off create an overhead hazard for a tall vehicle?
  104. 104. A cardboard box lies in your lane. Why should you not assume it is harmless?
  105. 105. You can see the nose of a van projecting from a blind alley, but not its driver. What should you anticipate?
  106. 106. You approach a stopped transit bus. What hidden hazard should you anticipate?
  107. 107. An ice cream truck is stopped beside children. What should this alert you to?
  108. 108. A car signals into a narrow driveway. Why should you allow for more than a brief slowdown?
  109. 109. A rider ahead looks over a shoulder without signaling. What possibility should you prepare for?
  110. 110. Another vehicle must leave a lane that ends just ahead. Why is this relevant even when you remain in your own lane?
  111. 111. A CDL holder is convicted of a non-parking traffic offense while driving a personal car. When must the current employer be notified?
  112. 112. You receive notice that your license is suspended. What is the federal deadline for notifying your employer?
  113. 113. Can a qualifying DUI conviction in a personal vehicle affect a CDL holder’s commercial qualification?
  114. 114. For a first qualifying alcohol-DUI conviction in a CMV not transporting placarded HazMat, what federal major-offense disqualification normally applies?
  115. 115. A driver commits two qualifying serious traffic violations in separate CMV incidents within three years. What disqualification applies?
  116. 116. Your vehicle is subject to an out-of-service order. Does a dispatcher’s delivery instruction allow you to ignore it?
  117. 117. May an employer knowingly use a CMV driver who holds more than one driver’s license?
  118. 118. What alcohol concentration meets the federal per-se threshold while operating a CMV that requires a CDL?
  119. 119. For an apportioned vehicle, should IRP distance records omit empty or bobtail travel?
  120. 120. What should trip records for IFTA fuel-tax reporting document?
  121. 121. Without a permit or applicable exception, what is California’s general maximum outside width for a truck body or load?
  122. 122. Your truck meets the general 102-inch width rule. Does that alone authorize travel on a local road posted with a lawful 96-inch restriction?
  123. 123. For an ordinary freight truck without a special permit or exception, what is the maximum vehicle-and-load height in California?
  124. 124. Your loaded truck is 13 feet 10 inches high. Does being below the general 14-foot limit mean every highway is safe for it?
  125. 125. What basic California length limit applies to an ordinary single-unit freight truck without a permit or special exception?
  126. 126. You drive a three-axle truck on a California highway posted 70 mph. What is your maximum speed in otherwise safe conditions?
  127. 127. A three-axle truck cruises on a divided highway with three lanes in its direction, no designated truck lanes, and no turn or route exception. Which lane should it normally use?
  128. 128. A divided highway has four lanes in your direction and no designated truck lanes. Besides the far-right lane, which lane may a three-axle truck normally use?
  129. 129. A private GPS suggests a truck route through California. How should you check whether that State route is legal for your truck configuration?
  130. 130. For a 53-foot STAA semitrailer with two rear axles, what maximum kingpin-to-rearmost-axle distance does Caltrans list?
  131. 131. An STAA truck exits at a Service Access S-sign. What access does that sign identify?
  132. 132. Without an applicable exception or permit, what general overall weight ceiling does Caltrans list for a loaded truck combination?
  133. 133. Under CVC 35550(a), without an exception, what is the general maximum weight on one complete axle?
  134. 134. Your steering-axle tires would exceed their manufacturer-rated capacity even though the axle is below 20,000 pounds. Is the load acceptable?
  135. 135. Your combination weighs less than 80,000 pounds overall. What additional weight check is still necessary?
  136. 136. An ordinary load with no special exception projects forward of a truck equipped with a front bumper. What is the general maximum beyond that bumper?
  137. 137. Without an applicable exception, rear cargo may extend beyond its last support by at most what fraction of the carrying vehicle’s wheelbase?
  138. 138. Which agency issues oversize/overweight transportation permits for California State highways?
  139. 139. You hold an annual transportation permit. Should you still check current short-term route restrictions before travel?
  140. 140. Your truck meets the general size and weight limits. Can a particular California State route still restrict it?
  141. 141. Your vehicle was operating normally yesterday. What inspection is needed for the next trip?
  142. 142. A hot engine has a see-through coolant reservoir with level markings. How can you check the level without opening the hot system?
  143. 143. A breakdown forces your truck to stop on the highway shoulder. Which lights should you switch on immediately to warn approaching traffic?
  144. 144. In its basic steering-defect guidance, what amount of steering-wheel free play does the California CDL handbook warn can make steering difficult?
  145. 145. A freight container is designed to transfer between a truck chassis, a train and a ship. What kind of container is it?
  146. 146. Why should a driver not use water on burning gasoline or energized electrical equipment?
  147. 147. Before adding the separate air-brake lag factor where applicable, which three distances make up the handbook’s basic stopping-distance model?
  148. 148. A newer streamlined truck climbed a hill in a relatively high gear. Should you automatically use that same gear to descend?
  149. 149. Two legal parking spaces are equally suitable for your truck. One allows a forward exit; the other requires backing into traffic. Which is preferable?
  150. 150. A loaded tractor and its loaded trailer are weighed together. Which term describes their actual combined weight?
Review all 150 questions with answers

  1. Who is ultimately responsible for the safe operation of a commercial vehicle after an inspection?

    Correct answer: The driver

    The driver remains responsible for operating the vehicle safely, even when maintenance personnel performed repairs.

    Source: CA Commercial Driver Handbook § 2.1.2 Vehicle Inspection ↗

  2. Which items should a commercial driver monitor during a trip for signs of trouble?

    Correct answer: Gauges and the vehicle through sight, sound, smell, and feel

    Trip inspection includes watching gauges and using the senses to detect developing problems.

    Source: CA Commercial Driver Handbook § 2.1.2 Trip Inspection ↗

  3. What minimum tread depth is required in every major groove of a commercial vehicle’s front tires?

    Correct answer: 4/32 inch

    Front tires require at least 4/32 inch; other tires require at least 2/32 inch.

    Source: CA Commercial Driver Handbook § 2.1.3 Tire Problems ↗

  4. Which tire placement is prohibited on the front wheels of a bus?

    Correct answer: Regrooved, recapped, or retreaded tires

    A bus may not use regrooved, recapped, or retreaded tires on its front wheels.

    Source: CA Commercial Driver Handbook § 2.1.3 Tire Problems ↗

  5. What can rust around a commercial vehicle’s wheel nuts indicate?

    Correct answer: The nuts may be loose

    Rust trails around wheel nuts can be evidence of movement and looseness.

    Source: CA Commercial Driver Handbook § 2.1.3 Wheel and Rim Problems ↗

  6. Why is excessive steering-wheel play a serious inspection defect?

    Correct answer: It can make the vehicle difficult to steer

    Excessive play can prevent precise steering control and must be investigated.

    Source: CA Commercial Driver Handbook § 2.1.3 Steering System Defects ↗

  7. Which warning equipment is a standard option for a parked commercial vehicle?

    Correct answer: Three red reflective warning triangles

    Commercial emergency equipment includes approved warning devices such as three red reflective triangles.

    Source: CA Commercial Driver Handbook § 2.1.3 Emergency Equipment ↗

  8. During the CDL vehicle inspection test, what must an applicant do when identifying an item?

    Correct answer: Point to or touch it, name it, and explain why it is inspected

    The inspection test requires identification of the component and an explanation of its safety purpose or condition.

    Source: CA Commercial Driver Handbook § 2.1.4 CDL Vehicle Inspection Test ↗

  9. What is the principal method for controlling speed on a long downgrade?

    Correct answer: Use the engine’s braking effect in a suitable low gear

    Selecting a low gear before descending lets engine braking control speed while preserving the service brakes.

    Source: CA Commercial Driver Handbook § 2.6.6 Speed on Downgrades ↗

  10. When should a commercial driver select the proper low gear for a downgrade?

    Correct answer: Before starting down the grade

    The gear must be selected before descending because shifting later may be unsafe or impossible.

    Source: CA Commercial Driver Handbook § 2.6.6 Speed on Downgrades ↗

  11. How should speed be chosen when fog or darkness limits the view ahead?

    Correct answer: So the vehicle can stop within the visible distance

    A driver must always be able to stop within the distance that can be seen clearly.

    Source: CA Commercial Driver Handbook § 2.6.4 Speed and Distance Ahead ↗

  12. Under the handbook length rule below 40 mph, what is the minimum following time for a 50-foot commercial vehicle?

    Correct answer: 5 seconds

    The basic minimum is one second per 10 feet of vehicle length: five seconds for 50 feet. Leave more space when road, traffic, or weather conditions require it.

    Source: CA Commercial Driver Handbook § 2.7.1 Space Ahead ↗

  13. What extra following time should be added when traveling above 40 mph?

    Correct answer: One additional second

    Apply the length rule, then add one second when speed exceeds 40 mph.

    Source: CA Commercial Driver Handbook § 2.7.1 Space Ahead ↗

  14. How should a commercial driver respond to a vehicle following too closely?

    Correct answer: Increase the space ahead and avoid sudden changes

    More room ahead reduces the need for sudden braking and gives the tailgater an opportunity to pass.

    Source: CA Commercial Driver Handbook § 2.7.2 Space Behind ↗

  15. Why might an empty cargo van require more overhead clearance than the same van when loaded?

    Correct answer: Its suspension may sit higher when empty

    Removing cargo can raise the vehicle, so a clearance that worked while loaded may no longer be sufficient.

    Source: CA Commercial Driver Handbook § 2.7.4 Space Overhead ↗

  16. When a large vehicle needs extra room to complete a right turn, what should the driver avoid doing at the start?

    Correct answer: Swinging wide to the left

    A left swing can invite a following vehicle to pass on the right and enter the truck’s turning path.

    Source: CA Commercial Driver Handbook § 2.7.6 Space for Turns ↗

  17. Who is responsible for recognizing an overload or poorly balanced cargo?

    Correct answer: The driver

    The driver is responsible for inspecting the cargo and recognizing overloads, imbalance, and insecure loading.

    Source: CA Commercial Driver Handbook § 3.1 Inspecting Cargo ↗

  18. For an accessible, unsealed truck load, when must the driver first recheck cargo securement after starting the trip?

    Correct answer: Within the first 50 miles

    Inspect within the first 50 miles and correct any insecure loading. Separate exceptions apply to sealed loads the driver is ordered not to open and loads that cannot practicably be inspected.

    Source: 49 CFR 392.9(b): Cargo inspection and exceptions ↗

  19. After the initial check of an accessible, unsealed truck load, when is the next cargo reinspection required?

    Correct answer: At a duty-status change, 3 hours of driving, or 150 miles, whichever occurs first

    Recheck securement at the first of these events: a change of duty status, three driving hours, or 150 miles. Make needed adjustments before continuing.

    Source: 49 CFR 392.9(b): Cargo inspection and exceptions ↗

  20. What does Gross Vehicle Weight describe?

    Correct answer: The actual total weight of a single vehicle and its load

    GVW is the actual total weight of one vehicle, including its load.

    Source: CA Commercial Driver Handbook § 3.2.1 Definitions ↗

  21. Where should the heaviest cargo generally be placed to reduce rollover risk?

    Correct answer: As low as possible

    A lower center of gravity improves stability, especially in curves and emergency maneuvers.

    Source: CA Commercial Driver Handbook § 3.2.3 Do Not Be Top-Heavy ↗

  22. What can result from placing too little weight on the front axle?

    Correct answer: The steering axle may be too light for safe steering

    Insufficient front-axle weight can reduce steering control.

    Source: CA Commercial Driver Handbook § 3.2.4 Balance the Weight ↗

  23. What aggregate working load limit must a cargo securement system provide?

    Correct answer: At least one-half the weight of the secured article or group

    Aggregate working load limit must cover at least half the restrained cargo weight. Direct tie-downs count differently from tie-downs passing over or around cargo; do not simply add every strap rating.

    Source: FMCSA Cargo Securement Rules: Minimum Working Load Limit ↗

  24. Under the general federal tie-down rule, a 7-foot article is not blocked against forward movement. What is the minimum number of tie-downs?

    Correct answer: Two

    An unblocked article longer than 5 feet but shorter than 10 feet needs at least two tie-downs under the general rule. Required working load limit and any cargo-specific rules still apply.

    Source: FMCSA Cargo Securement Rules: Minimum Number of Tiedowns ↗

  25. Why should a driver check cargo covers in the mirrors while traveling?

    Correct answer: A loose cover can tear away, expose cargo, or block someone’s view

    A flapping cover can detach and create a visibility or roadway hazard.

    Source: CA Commercial Driver Handbook § 3.3.4 Covering Cargo ↗

  26. You must back into an unfamiliar loading space. What should you do before beginning the maneuver?

    Correct answer: Get out and examine the planned path, including side and overhead clearance

    Inspect the complete path before backing. Walking around lets you identify hazards and clearances that may not be visible from the driving position.

    Source: CA Commercial Driver Handbook § 2.2.4 Backing Safely — Look at Your Path ↗

  27. While backing slowly, you become unsure whether the right rear corner will clear an obstacle. What is the safest next step?

    Correct answer: Stop, secure the vehicle and get out to check the path

    If you are unsure of the path or clearance, stop and check it from outside the vehicle. Mirrors have blind spots, and moving slowly does not make uncertain clearance safe.

    Source: CA Commercial Driver Handbook § 2.2.4 Backing Safely — Use Mirrors on Both Sides ↗

  28. Your trailer is moving off the intended backing path and repeated small corrections are not restoring its position. What should you do?

    Correct answer: Pull forward to reposition before trying again

    A pull-up is an appropriate way to reposition during backing. Correct drift early and back slowly instead of continuing an increasingly poor approach.

    Source: CA Commercial Driver Handbook § 2.2.5 Backing with a Trailer — Pull Forward ↗

  29. The drive wheels begin spinning as you accelerate from a stop on a snowy road. What response does the handbook recommend?

    Correct answer: Ease off the accelerator to stop the wheel spin

    Too much power on a low-traction surface can make the drive wheels spin and cause loss of control. Remove your foot from the accelerator and use gradual acceleration suited to the available traction.

    Source: CA Commercial Driver Handbook § 2.2.1 Accelerating ↗

  30. You are approaching a curve in a commercial vehicle with a manual transmission. When should you reduce speed and select the appropriate lower gear?

    Correct answer: Before entering the curve

    Slow to a safe speed and select the proper gear before the curve. This helps you maintain stable control rather than needing a gear change during the turn.

    Source: CA Commercial Driver Handbook § 2.3.1 Manual Transmissions — Before Entering a Curve ↗

  31. A vehicle appears small and distant in your convex mirror. What should you remember before judging the available gap?

    Correct answer: The vehicle can be closer than its mirror image suggests

    Convex mirrors provide a wider view, but objects appear smaller and farther away than they really are. Allow for this distortion when judging traffic position.

    Source: CA Commercial Driver Handbook § 2.4.2 Seeing to the Sides and Rear — How to Use Mirrors ↗

  32. Before a trip with a trailer, which position allows an accurate check of mirror adjustment?

    Correct answer: With the tractor and trailer aligned straight

    Check mirror adjustment before the trip with the trailer straight. Showing part of your own vehicle provides a reference for judging other objects in the mirrors.

    Source: CA Commercial Driver Handbook § 2.4.2 Seeing to the Sides and Rear — Mirror Adjustment ↗

  33. You are looking 12 to 15 seconds ahead as recommended for commercial driving. How should you also monitor the nearer road?

    Correct answer: Shift attention between distant and nearby conditions

    Looking well ahead does not replace monitoring nearby hazards. The handbook describes shifting attention back and forth between near and far to maintain awareness.

    Source: CA Commercial Driver Handbook § 2.4.1 Seeing Ahead ↗

  34. What is the safest way to make routine mirror checks while traveling?

    Correct answer: Use brief checks and return attention to the road ahead

    Frequent, brief mirror checks help you monitor surrounding traffic without traveling a long distance while looking away from the road ahead.

    Source: CA Commercial Driver Handbook § 2.4.2 Seeing to the Sides and Rear — How to Use Mirrors ↗

  35. Before departure, why should you secure loose tools and other articles in the cab?

    Correct answer: They can obstruct controls or strike occupants during a collision

    Loose articles can interfere with vehicle controls or become impact hazards. Secure them before driving rather than relying on their current resting position.

    Source: CA Commercial Driver Handbook § 2.1.5 Seven-Step Inspection Method — Get in the Vehicle ↗

  36. A following driver wants to pass your truck. Should you wave them around as a guarantee that the road is clear?

    Correct answer: No, let that driver make their own safe passing decision

    Do not direct other traffic into a pass; you cannot guarantee the maneuver will remain safe.

    Source: CA Commercial Driver Handbook § 2.5.1 Signal Your Intentions ↗

  37. Your commercial vehicle must stop on the highway shoulder. How soon must required emergency warning devices be placed?

    Correct answer: Within 10 minutes

    Use flashers immediately and place the required warning devices promptly.

    Source: CA Commercial Driver Handbook § 2.5.2 Communicating Your Presence ↗

  38. On a straight divided highway with a clear view, what spacing does the handbook give for the three warning devices behind a stopped truck?

    Correct answer: 10, 100, and 200 feet toward approaching traffic

    All three warn traffic approaching from the direction serving that roadway. Adjust for an obstructed view.

    Source: CA Commercial Driver Handbook § 2.5.2 One-Way or Divided Highway ↗

  39. A truck stops beside a straight two-way road with clear sightlines. Why are warning devices needed both ahead and behind?

    Correct answer: Traffic can approach the stopped vehicle from either direction

    The two-way layout includes warnings about 100 feet in each direction plus one close to the vehicle.

    Source: CA Commercial Driver Handbook § 2.5.2 Two-Way or Undivided Highway ↗

  40. At dusk in rain, are identification and clearance lights alone sufficient to make your truck visible?

    Correct answer: No, use headlights too

    Clearance lamps do not replace headlights in reduced visibility.

    Source: CA Commercial Driver Handbook § 2.5.2 When It Is Hard to See ↗

  41. You keep your hands on the wheel but become absorbed in a stressful conversation. What type of distraction can this create?

    Correct answer: Mental distraction from driving

    Attention can leave the driving task even when your eyes and hands appear correctly positioned.

    Source: CA Commercial Driver Handbook § 2.9.3 Types of Distractions ↗

  42. When is the best time to program the route into your navigation system?

    Correct answer: Before beginning to drive

    Plan and set up navigation before moving rather than divide attention in traffic.

    Source: CA Commercial Driver Handbook § 2.9.6 Do Not Drive Distracted ↗

  43. A car ahead drifts within its lane while its driver looks down repeatedly. How should you react?

    Correct answer: Leave extra room and anticipate an unexpected movement

    Recognizing distraction in another driver helps you protect your own space.

    Source: CA Commercial Driver Handbook § 2.9.7 Other Distracted Drivers ↗

  44. An aggressive driver tries to provoke you. What is the safer response?

    Correct answer: Create separation and avoid challenging the driver

    Do not turn another driver’s aggression into a contest.

    Source: CA Commercial Driver Handbook § 2.10.3 Confronted by an Aggressive Driver ↗

  45. Snow covers the truck’s mirrors and side windows before departure. What is required for a safe start?

    Correct answer: Clear them as well as the windshield

    You need usable views around the vehicle before entering traffic.

    Source: CA Commercial Driver Handbook § 2.13.1 Windows and Mirrors ↗

  46. Why is a leaking exhaust especially dangerous when the cab windows are closed?

    Correct answer: Carbon monoxide may accumulate in the cab

    Check exhaust defects; a closed cab can retain poisonous exhaust gases.

    Source: CA Commercial Driver Handbook § 2.13.1 Exhaust System ↗

  47. After water enters a truck’s brakes, what behavior can occur?

    Correct answer: Weak, uneven, or grabbing brake action

    Water can change braking behavior and contribute to wheel lock or pulling.

    Source: CA Commercial Driver Handbook § 2.13.2 Wet Brakes ↗

  48. A properly inflated tire’s pressure rises during hot-weather operation. Should you bleed air to its cold-pressure reading?

    Correct answer: No, it could become underinflated when it cools

    Heat raises pressure; follow cold-inflation specifications rather than vent hot tires.

    Source: CA Commercial Driver Handbook § 2.14.1 Tires ↗

  49. During a hot-weather stop, a tire is too hot to touch. What does the handbook direct you to do?

    Correct answer: Remain stopped until it cools

    Continuing with an overheated tire increases the risk of failure or fire.

    Source: CA Commercial Driver Handbook § 2.14.1 Tires ↗

  50. When is it safe to open the pressurized radiator system for a coolant check?

    Correct answer: After it has cooled, following the vehicle’s instructions

    Hot pressurized coolant can cause severe burns. Engine shutdown alone does not release that danger.

    Source: CA Commercial Driver Handbook § 2.14.1 Engine Coolant ↗

  51. Dark patches of tar have risen to the road surface in extreme heat. What hazard should you expect?

    Correct answer: Reduced traction on the slick patches

    Heat-softened surface tar can be slippery.

    Source: CA Commercial Driver Handbook § 2.14.2 Driving in the Heat ↗

  52. How should a manual-transmission truck cross railroad tracks?

    Correct answer: Select an appropriate gear before crossing and do not shift on the tracks

    Avoid a missed shift or loss of movement where a train could approach.

    Source: CA Commercial Driver Handbook § 2.15.5 Crossing the Tracks ↗

  53. One train has passed a crossing with two tracks. What must you check before proceeding?

    Correct answer: Whether another train is approaching on either track

    A train can conceal another train. Obey warning devices and verify the crossing is clear.

    Source: CA Commercial Driver Handbook § 2.15.3 Double Tracks Require a Double Check ↗

  54. A railroad crossing has no active lights or gates. What does that mean for your decision?

    Correct answer: You must look and listen and determine that crossing is safe

    The absence of active warning equipment is not evidence that no train is coming.

    Source: CA Commercial Driver Handbook § 2.15.1 Passive Crossings ↗

  55. Why is listening for a horn alone an unsafe crossing check?

    Correct answer: Some trains do not sound a horn and cab noise may mask it

    Use active observation and obey crossing controls rather than rely on sound alone.

    Source: CA Commercial Driver Handbook § 2.15.3 Do Not Expect to Hear a Train ↗

  56. The front wheels slide and the truck continues straight despite steering input. What should you avoid?

    Correct answer: Adding more harsh steering or braking

    A front-wheel skid needs traction recovery; greater steering force does not create grip.

    Source: CA Commercial Driver Handbook § 2.19.3 Front-Wheel Skids ↗

  57. Excessive braking has locked the rear drive wheels of a truck without effective ABS intervention. What is the first recovery action?

    Correct answer: Stop braking so the wheels can roll again

    Restore rolling traction before completing the steering correction. This is not normal ABS braking advice.

    Source: CA Commercial Driver Handbook § 2.19.2 Drive-Wheel Braking Skid ↗

  58. After a collision, you are uninjured and able to act. What is an immediate priority?

    Correct answer: Prevent another collision at the scene

    Protect the area, request assistance, and keep emergency access clear.

    Source: CA Commercial Driver Handbook § 2.20.1 Protect the Area ↗

  59. You stop to help at a collision in which your truck was not involved. Where should you park?

    Correct answer: Away from the immediate scene so emergency vehicles have space

    Helping should not obstruct rescuers or create a second hazard.

    Source: CA Commercial Driver Handbook § 2.20.1 Protect the Area ↗

  60. Smoke indicates a vehicle fire while you are driving. Where should you stop if you can safely move off the road?

    Correct answer: In an open area away from fuel stations and combustible surroundings

    Stop safely away from things that could ignite and notify emergency services.

    Source: CA Commercial Driver Handbook § 2.21.3 Pull Off the Road ↗

  61. Why should you avoid opening the hood fully during an engine fire?

    Correct answer: It can feed oxygen to the fire

    Shut the engine off when safe and avoid actions that intensify the fire.

    Source: CA Commercial Driver Handbook § 2.21.3 Keep the Fire From Spreading ↗

  62. Smoke comes from a closed box trailer, and the cargo may be hazardous. Should you open its doors to investigate?

    Correct answer: No, keep them closed and summon emergency help

    Opening the doors can rapidly feed a cargo fire; unknown hazardous cargo adds further danger.

    Source: CA Commercial Driver Handbook § 2.21.3 Keep the Fire From Spreading ↗

  63. For a small fire you can safely tackle with the correct extinguisher and an escape path, where should you aim?

    Correct answer: At the base of the fire

    The extinguishing agent must reach the burning material rather than only the rising flames.

    Source: CA Commercial Driver Handbook § 2.21.3 Extinguish the Fire ↗

  64. You do not know which extinguishing agent is safe for the burning cargo. What should you do?

    Correct answer: Stay clear and wait for trained firefighters

    An unsuitable agent can worsen a fire, especially when hazardous materials are involved.

    Source: CA Commercial Driver Handbook § 2.21.3 Use the Correct Fire Extinguisher ↗

  65. A B:C extinguisher is intended for which hazards?

    Correct answer: Flammable-liquid and electrical fires

    Match the rating to the fire; do not assume one extinguisher covers every material.

    Source: CA Commercial Driver Handbook § 2.21.3 Use the Correct Fire Extinguisher ↗

  66. What is the purpose of blocks secured snugly around cargo?

    Correct answer: Prevent the cargo from sliding

    Blocking restrains movement rather than merely filling unused cargo space.

    Source: CA Commercial Driver Handbook § 3.3.1 Blocking and Bracing ↗

  67. What does bracing between upper cargo and the compartment structure help prevent?

    Correct answer: Movement of the load

    Bracing is part of the load-restraint system, not a substitute for inspections.

    Source: CA Commercial Driver Handbook § 3.3.1 Blocking and Bracing ↗

  68. Why inspect a front-end header board before carrying a load?

    Correct answer: It helps restrain forward cargo movement toward the cab

    A sound front-end structure protects against cargo moving forward in a sudden stop.

    Source: CA Commercial Driver Handbook § 3.3.3 Header Boards ↗

  69. You are ordered not to open a sealed load. Which duty still remains?

    Correct answer: Check compliance with gross and axle weight limits

    A sealed-load inspection exception does not make an overweight vehicle lawful.

    Source: CA Commercial Driver Handbook § 3.3.5 Sealed and Containerized Loads ↗

  70. What makes a dry-bulk tank load demanding in a sharp curve?

    Correct answer: A high center of gravity and possible load movement

    Reduce speed before curves and avoid abrupt maneuvers.

    Source: CA Commercial Driver Handbook § 3.4.1 Dry Bulk ↗

  71. Why is suspended meat cargo a special concern on an off-ramp?

    Correct answer: It can swing and make a high load unstable

    The suspended load calls for conservative cornering speed.

    Source: CA Commercial Driver Handbook § 3.4.2 Hanging Meat ↗

  72. How can live animals affect trailer stability?

    Correct answer: Their movement can shift the center of gravity

    Moving livestock remains a handling concern even when the load is contained.

    Source: CA Commercial Driver Handbook § 3.4.3 Livestock ↗

  73. Before taking an oversize or overweight load on California roads, what should you determine?

    Correct answer: Required Caltrans permits, route conditions, and any escort restrictions

    Special loads may require permits and limits on route, time, signs, and escort arrangements.

    Source: CA Commercial Driver Handbook § 3.4.4 Oversized Loads ↗

  74. What does axle weight measure?

    Correct answer: Weight transmitted to the ground by an axle or axle group

    Axle loading is a separate limit from the vehicle’s total gross weight.

    Source: CA Commercial Driver Handbook § 3.2.1 Definitions — Axle Weight ↗

  75. Your load is within the legal maximum. Does that guarantee it is safe for bad weather or a mountain route?

    Correct answer: No, conditions can require operating below legal maximum weight

    Legal limits do not replace judgment about braking, traction, and the route.

    Source: CA Commercial Driver Handbook § 3.2.2 Legal Weight Limits ↗

  76. How should you determine suitable shift points for an unfamiliar commercial vehicle?

    Correct answer: Learn its specified engine-speed and road-speed ranges

    Shift patterns and useful rpm ranges vary between vehicles.

    Source: CA Commercial Driver Handbook § 2.3.1 Manual Transmissions ↗

  77. Why does the handbook advise turning a retarder off on a slippery road?

    Correct answer: Its drive-wheel braking can cause a skid

    A retarder acts through the drive wheels; reduced grip can make that braking unsafe.

    Source: CA Commercial Driver Handbook § 2.3.4 Retarders ↗

  78. An approaching driver leaves bright lights on. What should you do?

    Correct answer: Look toward the right edge reference without staring into the glare

    Avoid adding glare or losing sight of your own lane; reduce speed when needed.

    Source: CA Commercial Driver Handbook § 2.11.5 Night Driving Procedures ↗

  79. Why clean both sides of the windshield before a night trip?

    Correct answer: Dirt can scatter light and worsen glare

    Interior film as well as exterior dirt can obscure the road under bright lights.

    Source: CA Commercial Driver Handbook § 2.11.4 Vehicle Factors ↗

  80. Your eyelids are heavy and you are struggling to stay alert. What is the safe response?

    Correct answer: Stop at a safe place and sleep

    Temporary stimulation does not replace sleep or make continued drowsy driving safe.

    Source: CA Commercial Driver Handbook § 2.11.2 Driver Factors — Drowsiness ↗

  81. You see dense fog ahead while approaching a safe truck stop. What is the preferable choice?

    Correct answer: Leave the roadway safely and wait for visibility to improve

    A safe off-road waiting area is preferable to entering severely limited visibility.

    Source: CA Commercial Driver Handbook § 2.12 Driving in Fog ↗

  82. Why should you avoid using another vehicle’s taillights as your only guide through fog?

    Correct answer: That vehicle may be stopped off the roadway

    Identify your own road path and leave enough distance rather than blindly following lights.

    Source: CA Commercial Driver Handbook § 2.12 Driving in Fog ↗

  83. When should you learn how to fit the chains carried for your drive tires?

    Correct answer: Before encountering conditions that require them

    Check fit and condition in advance so the equipment can be used correctly when required.

    Source: CA Commercial Driver Handbook § 2.13.1 Vehicle Checks ↗

  84. Which combination matters when selecting a safe descent speed?

    Correct answer: Vehicle weight, grade length and steepness, road and weather

    Different loads and grades can demand different descent speeds even under the same posted limit.

    Source: CA Commercial Driver Handbook § 2.16.1 Select a Safe Speed ↗

  85. Your truck’s brakes have failed on a downgrade and an escape ramp is available. What should you do?

    Correct answer: Use the escape ramp rather than pass it hoping to regain braking

    A designated escape ramp offers a means to stop a runaway vehicle; delay increases danger.

    Source: CA Commercial Driver Handbook § 2.17.3 Brake Failure ↗

  86. A hydraulic service-brake pedal goes to the floor. Which action may briefly restore hydraulic pressure?

    Correct answer: Pump the brake pedal while seeking a safe way to stop

    This is a hydraulic-pressure-loss technique, not normal ABS braking or an air-brake recovery method. Use other appropriate emergency measures and stop.

    Source: CA Commercial Driver Handbook § 2.17.3 Loss of Hydraulic Pressure ↗

  87. A truck tire fails, but there is no immediate collision ahead. What is the initial response?

    Correct answer: Hold the steering firmly and avoid braking until speed falls

    Control the vehicle first, then brake gently and stop safely for an inspection.

    Source: CA Commercial Driver Handbook § 2.17.4 Tire Failure ↗

  88. Does buying a cold medicine without a prescription prove it is safe before commercial driving?

    Correct answer: No, it may cause drowsiness or impair driving

    Check warnings and appropriate medical advice; over-the-counter availability is not a safety guarantee.

    Source: CA Commercial Driver Handbook § 2.22.2 Other Drugs ↗

  89. You become too ill to operate your truck safely. What should you do?

    Correct answer: Stop safely rather than continue the scheduled trip

    Illness can make continued driving unsafe even without alcohol or medication.

    Source: CA Commercial Driver Handbook § 2.22.3 Illness ↗

  90. Why must a commercial driver keep hazardous-material shipping papers readily accessible?

    Correct answer: Responders may need to identify the cargo when the driver cannot speak

    Accessible cargo information helps emergency personnel choose suitable precautions.

    Source: CA Commercial Driver Handbook § 2.23.2 Communicate the Risk ↗

  91. Who must supervise your public-road driving with a CLP?

    Correct answer: An authorized CDL holder with the appropriate class and endorsements

    The supervisor must be physically present in the prescribed seating position and directly observe the learner.

    Source: 49 CFR 383.25(a)(1) ↗

  92. What minimum initial CLP holding period applies before a CDL skills test?

    Correct answer: 14 days

    Passing knowledge tests does not remove this initial waiting period.

    Source: 49 CFR 383.25(e) ↗

  93. Does a CLP replace the need for a valid underlying driver’s license?

    Correct answer: No, a valid license from the issuing jurisdiction is also required

    The learner permit operates together with the valid underlying license.

    Source: 49 CFR 383.25(a)(2) ↗

  94. A first-time Class A applicant in 2026 has no training exemption. Does self-study alone satisfy ELDT?

    Correct answer: No, required entry-level training must also be completed

    Question practice prepares knowledge but does not replace regulated training.

    Source: FMCSA — About the ELDT Regulations ↗

  95. A Class B holder now seeks Class A with no exemption. Is the upgrade among the ELDT-covered applications?

    Correct answer: Yes

    The Class B-to-A upgrade is specifically covered.

    Source: FMCSA — About the ELDT Regulations ↗

  96. A driver received Class A before February 7, 2022. Is ELDT automatically required again solely because that existing qualification predates the rule?

    Correct answer: No, ELDT is not retroactive for that qualification

    A later new covered class or endorsement can create a separate requirement.

    Source: FMCSA — ELDT non-retroactivity ↗

  97. Without an applicable waiver, what minimum behind-the-wheel training does California require for an original Class A or B CDL?

    Correct answer: 15 hours

    California requires documented practical training in addition to federal ELDT.

    Source: ELDT FAQs — California behind-the-wheel requirement ↗

  98. For California interstate NI drivers in September 2026, who submits medical exam information through the National Registry?

    Correct answer: The registered medical examiner

    The current electronic process differs from intrastate submission options.

    Source: NRII — July 27, 2026 implementation ↗

  99. Your Clearinghouse status is prohibited, but your CDL card has not expired. May you operate a CMV?

    Correct answer: No

    Possession of the card does not override the loss of commercial driving privileges.

    Source: Drug and Alcohol Clearinghouse — prohibited status ↗

  100. Which set describes the CDL skills assessment?

    Correct answer: Vehicle inspection, basic controls, and road driving

    Passing practice questions does not demonstrate these practical skills.

    Source: How to Apply for a CDL — skills test ↗

  101. A car near an exit brakes repeatedly and drifts toward the through lane. What should you do before it becomes an emergency?

    Correct answer: Plan space and a safe response to a possible sudden lane change

    Recognizing the developing hazard gives time for a controlled response.

    Source: CA Commercial Driver Handbook § 2.8.4 Always Have a Plan ↗

  102. A temporary work lane is narrower than the normal lane. What demands extra attention from a truck driver?

    Correct answer: Side clearance, surface changes, workers, and nearby traffic

    Construction changes the available space and can create unexpected movements.

    Source: CA Commercial Driver Handbook § 2.8.2 Hazardous Roads — Work Zones ↗

  103. Why can a sharp pavement-edge drop-off create an overhead hazard for a tall vehicle?

    Correct answer: The vehicle may tilt toward roadside branches or signs

    A tilted body can strike something that was clear when the vehicle was level.

    Source: CA Commercial Driver Handbook § 2.8.2 Hazardous Roads — Drop Off ↗

  104. A cardboard box lies in your lane. Why should you not assume it is harmless?

    Correct answer: It may contain heavy material or damage vehicle components

    Identify debris early so avoidance does not require a sudden unsafe maneuver.

    Source: CA Commercial Driver Handbook § 2.8.2 Hazardous Roads — Foreign Objects ↗

  105. You can see the nose of a van projecting from a blind alley, but not its driver. What should you anticipate?

    Correct answer: The driver may enter without seeing your truck

    Prepare for movement where the other driver’s view may be obstructed.

    Source: CA Commercial Driver Handbook § 2.8.3 Drivers Who Are Hazards — Blocked Vision ↗

  106. You approach a stopped transit bus. What hidden hazard should you anticipate?

    Correct answer: Passengers crossing from in front of or behind it

    The bus can conceal people from you and conceal your truck from them.

    Source: CA Commercial Driver Handbook § 2.8.3 Drivers Who Are Hazards — Parked Vehicles ↗

  107. An ice cream truck is stopped beside children. What should this alert you to?

    Correct answer: A child may enter the road without checking traffic

    Reduce risk by anticipating unpredictable movement and preserving stopping space.

    Source: CA Commercial Driver Handbook § 2.8.3 Drivers Who Are Hazards — Ice Cream Trucks ↗

  108. A car signals into a narrow driveway. Why should you allow for more than a brief slowdown?

    Correct answer: It may need to stop for people or vehicles in the entrance

    A tight or obstructed turn may leave the car stopped partly in the roadway.

    Source: CA Commercial Driver Handbook § 2.8.3 Drivers Who Are Hazards — Drivers Signaling a Turn ↗

  109. A rider ahead looks over a shoulder without signaling. What possibility should you prepare for?

    Correct answer: A lane change or turn

    Body movement is a clue, not a guarantee; keep space for an unexpected maneuver.

    Source: CA Commercial Driver Handbook § 2.8.3 Driver Body Movement as a Clue ↗

  110. Another vehicle must leave a lane that ends just ahead. Why is this relevant even when you remain in your own lane?

    Correct answer: Its response may create a conflict with your path

    Anticipating how others may react allows earlier space management.

    Source: CA Commercial Driver Handbook § 2.8.3 Conflicts ↗

  111. A CDL holder is convicted of a non-parking traffic offense while driving a personal car. When must the current employer be notified?

    Correct answer: Within 30 days of conviction

    The employer-notification duty applies regardless of the type of vehicle driven.

    Source: FMCSA — Employer Notifications ↗

  112. You receive notice that your license is suspended. What is the federal deadline for notifying your employer?

    Correct answer: By the end of the next business day

    The deadline runs from receiving notice; do not substitute the longer conviction-reporting period.

    Source: FMCSA — Employer Notifications; 49 CFR 383.33 ↗

  113. Can a qualifying DUI conviction in a personal vehicle affect a CDL holder’s commercial qualification?

    Correct answer: Yes

    Major qualifying offenses in noncommercial vehicles can also result in commercial disqualification.

    Source: FMCSA — Disqualification for Major Offenses ↗

  114. For a first qualifying alcohol-DUI conviction in a CMV not transporting placarded HazMat, what federal major-offense disqualification normally applies?

    Correct answer: One year

    This scenario is the ordinary first major-offense case, not a repeat offense or the longer placarded-HazMat case.

    Source: FMCSA — Disqualification for Major Offenses ↗

  115. A driver commits two qualifying serious traffic violations in separate CMV incidents within three years. What disqualification applies?

    Correct answer: 60 days

    Repeated serious violations trigger disqualification even when neither is classified as a major offense.

    Source: FMCSA — Disqualification for Serious Traffic Violations ↗

  116. Your vehicle is subject to an out-of-service order. Does a dispatcher’s delivery instruction allow you to ignore it?

    Correct answer: No

    Employer instructions do not cancel an out-of-service order; violating it can result in disqualification.

    Source: FMCSA — Violation of Out-of-Service Order ↗

  117. May an employer knowingly use a CMV driver who holds more than one driver’s license?

    Correct answer: No

    Commercial licensing records are shared to identify disqualifications and improper multiple licenses.

    Source: FMCSA — Employer Notifications and CDLIS ↗

  118. What alcohol concentration meets the federal per-se threshold while operating a CMV that requires a CDL?

    Correct answer: 0.04%

    A lower reading is not a guarantee of safe or lawful driving.

    Source: FMCSA — BAC Standards ↗

  119. For an apportioned vehicle, should IRP distance records omit empty or bobtail travel?

    Correct answer: No, those movements also count

    Registration apportionment requires records of the vehicle’s accountable movements, not just paid loads.

    Source: IRP Handbook 10.030 — Accountable Vehicle Distance ↗

  120. What should trip records for IFTA fuel-tax reporting document?

    Correct answer: Trip distance by jurisdiction and supporting fuel purchases

    Retain the detailed travel and fuel evidence supporting the fuel-use return; a delivery invoice alone is insufficient.

    Source: IFTA FAQs — What records will I need? ↗

  121. Without a permit or applicable exception, what is California’s general maximum outside width for a truck body or load?

    Correct answer: 102 inches

    This is the general body/load limit; separately permitted safety devices and special vehicles have different provisions.

    Source: Caltrans — General Rule — CVC 35100(a) ↗

  122. Your truck meets the general 102-inch width rule. Does that alone authorize travel on a local road posted with a lawful 96-inch restriction?

    Correct answer: No, the local restriction must also be respected

    A city or county may impose the narrower limit on roads under its jurisdiction.

    Source: Caltrans — Cities & Counties — CVC 35100(c) ↗

  123. For an ordinary freight truck without a special permit or exception, what is the maximum vehicle-and-load height in California?

    Correct answer: 14 feet

    Measure from the roadway surface to the highest part of the vehicle or load.

    Source: Caltrans — CVC 35250 — general height limit ↗

  124. Your loaded truck is 13 feet 10 inches high. Does being below the general 14-foot limit mean every highway is safe for it?

    Correct answer: No, verify clearance along the actual route

    Legal vehicle height does not guarantee bridge clearance; vehicles above 13 feet 6 inches require route-safety determination.

    Source: Caltrans — CVC 35250; Low Clearances on State Routes ↗

  125. What basic California length limit applies to an ordinary single-unit freight truck without a permit or special exception?

    Correct answer: 40 feet

    Do not apply the different combination-vehicle or special bus provisions to an ordinary straight truck.

    Source: Caltrans — Legal Trucks — Length, Single Unit ↗

  126. You drive a three-axle truck on a California highway posted 70 mph. What is your maximum speed in otherwise safe conditions?

    Correct answer: 55 mph

    The truck-specific cap still applies; unsafe conditions or a lower posted limit can require less speed.

    Source: Caltrans — Reduced Speeds — CVC 22406(a) ↗

  127. A three-axle truck cruises on a divided highway with three lanes in its direction, no designated truck lanes, and no turn or route exception. Which lane should it normally use?

    Correct answer: The right-hand lane

    Use the right lane when the special four-or-more-lane provision and other exceptions do not apply.

    Source: Caltrans — CVC 21655(b) — no designated lanes ↗

  128. A divided highway has four lanes in your direction and no designated truck lanes. Besides the far-right lane, which lane may a three-axle truck normally use?

    Correct answer: The lane immediately left of the far-right lane

    This additional ordinary lane choice applies when there are at least four lanes in that direction.

    Source: Caltrans — CVC 21655(b) — four or more lanes ↗

  129. A private GPS suggests a truck route through California. How should you check whether that State route is legal for your truck configuration?

    Correct answer: Consult the official Caltrans Truck Network information

    Verify the vehicle category, route restrictions and local access rather than treating navigation advice as authorization.

    Source: Caltrans — Step 2 — determine State routes ↗

  130. For a 53-foot STAA semitrailer with two rear axles, what maximum kingpin-to-rearmost-axle distance does Caltrans list?

    Correct answer: 40 feet

    The single-axle case differs; meeting this dimension still does not authorize every road.

    Source: Caltrans — Step 1 — 53-foot STAA semitrailer ↗

  131. An STAA truck exits at a Service Access S-sign. What access does that sign identify?

    Correct answer: Up to one mile for food, fuel, lodging or repairs

    Service access is limited; it is not blanket permission to travel through local neighborhoods.

    Source: Caltrans — Step 2 — S-Sign, Service Access ↗

  132. Without an applicable exception or permit, what general overall weight ceiling does Caltrans list for a loaded truck combination?

    Correct answer: 80,000 pounds

    This is not a promise that every configuration may carry that weight; axle, equipment and route limits also apply.

    Source: Caltrans — Legal Trucks — Weight ↗

  133. Under CVC 35550(a), without an exception, what is the general maximum weight on one complete axle?

    Correct answer: 20,000 pounds

    The complete-axle limit is distinct from the limit on wheels supporting one end of that axle.

    Source: Caltrans — General Rule — CVC 35550(a) ↗

  134. Your steering-axle tires would exceed their manufacturer-rated capacity even though the axle is below 20,000 pounds. Is the load acceptable?

    Correct answer: No, tire load capacity must also be respected

    A legal axle total does not authorize overloading its tires.

    Source: Caltrans — General Rule — CVC 35550(c) ↗

  135. Your combination weighs less than 80,000 pounds overall. What additional weight check is still necessary?

    Correct answer: Check individual axles and axle groups against the applicable limits

    Axle grouping and spacing affect allowable weight; total vehicle weight alone is insufficient.

    Source: Caltrans — Axle Group Weight Chart — CVC 35551(a) ↗

  136. An ordinary load with no special exception projects forward of a truck equipped with a front bumper. What is the general maximum beyond that bumper?

    Correct answer: 3 feet

    The vehicle-hauling and special-equipment exceptions are not part of this scenario.

    Source: Caltrans — Front Loads — CVC 35406(a) ↗

  137. Without an applicable exception, rear cargo may extend beyond its last support by at most what fraction of the carrying vehicle’s wheelbase?

    Correct answer: Two-thirds

    Measure from the last support, not simply from the taillamps; semitrailers have a specified wheelbase measurement.

    Source: Caltrans — Rear Loads — CVC 35410 ↗

  138. Which agency issues oversize/overweight transportation permits for California State highways?

    Correct answer: Caltrans

    Caltrans handles the State Highway System; its permit authority is not universal permission for all local roads.

    Source: Caltrans — Transportation Permit Types — issuing authority ↗

  139. You hold an annual transportation permit. Should you still check current short-term route restrictions before travel?

    Correct answer: Yes, a current restriction may affect the permitted movement

    The permit does not remove the need to check current route conditions and restrictions.

    Source: Caltrans — Restrictions and Emergency Closures ↗

  140. Your truck meets the general size and weight limits. Can a particular California State route still restrict it?

    Correct answer: Yes, route-specific restrictions may apply

    Check restrictions on the intended route, including vehicle configuration and cargo type.

    Source: Caltrans — Current State Route Restrictions ↗

  141. Your vehicle was operating normally yesterday. What inspection is needed for the next trip?

    Correct answer: Inspect it before operating, including working clean lights and cargo securement

    A routine before-trip inspection can reveal new defects. Check the required vehicle components and load; yesterday’s condition is not proof of today’s safety.

    Source: CA Commercial Driver Handbook § 2.1.2 Types of Vehicle Inspections; 2.1.5 inspection method; 3.1 cargo inspection ↗

  142. A hot engine has a see-through coolant reservoir with level markings. How can you check the level without opening the hot system?

    Correct answer: Read the level through the reservoir wall while leaving the pressure cap closed

    A sight glass or transparent reservoir allows a visual check. Never open a hot pressurized cooling system.

    Source: CA Commercial Driver Handbook § 2.14.1 Vehicle Checks — Engine Coolant ↗

  143. A breakdown forces your truck to stop on the highway shoulder. Which lights should you switch on immediately to warn approaching traffic?

    Correct answer: The four-way emergency flashers

    Flashers warn that the vehicle is stopped. They do not replace the required warning devices that must also be placed promptly.

    Source: CA Commercial Driver Handbook § 2.5.2 Communicating Your Presence — When Parked at the Side of the Road ↗

  144. In its basic steering-defect guidance, what amount of steering-wheel free play does the California CDL handbook warn can make steering difficult?

    Correct answer: More than 10 degrees

    This is the handbook’s inspection warning, not a universal federal out-of-service limit. Federal steering-lash limits depend on wheel size and manual or power steering under 49 CFR 393.209.

    Source: CA Commercial Driver Handbook § 2.1.3 Steering System Defects ↗

  145. A freight container is designed to transfer between a truck chassis, a train and a ship. What kind of container is it?

    Correct answer: An intermodal container

    Intermodal means the container can be used across two or more transport modes; the cargo still needs appropriate securement.

    Source: FMCSA Cargo Securement Rules — 393.126 Intermodal Containers ↗

  146. Why should a driver not use water on burning gasoline or energized electrical equipment?

    Correct answer: It can spread burning gasoline or create an electrical-shock hazard

    Use a suitable extinguishing agent only when safe and trained to do so. Withdraw and get emergency help if the fire or material is uncertain.

    Source: CA Commercial Driver Handbook § 2.21.3 Fire Fighting — Use the Correct Fire Extinguisher ↗

  147. Before adding the separate air-brake lag factor where applicable, which three distances make up the handbook’s basic stopping-distance model?

    Correct answer: Perception, reaction and braking distances

    The vehicle moves while you recognize a hazard, while you respond and while the brakes slow it to a stop. Air brakes add a separate lag distance.

    Source: CA Commercial Driver Handbook § 2.6.1 Stopping Distance ↗

  148. A newer streamlined truck climbed a hill in a relatively high gear. Should you automatically use that same gear to descend?

    Correct answer: No, the descent may require a lower gear suited to that truck and grade

    Reduced drag and different engine performance can make the old same-gear rule unsuitable. Select the correct low gear before descending.

    Source: CA Commercial Driver Handbook § 2.16.2 Select the Right Gear Before Starting Down the Grade ↗

  149. Two legal parking spaces are equally suitable for your truck. One allows a forward exit; the other requires backing into traffic. Which is preferable?

    Correct answer: The space that allows you to pull forward when leaving

    Plan parking to avoid reversing when possible because you cannot see everything behind a large vehicle.

    Source: CA Commercial Driver Handbook § 2.2.4 Backing Safely ↗

  150. A loaded tractor and its loaded trailer are weighed together. Which term describes their actual combined weight?

    Correct answer: Gross combination weight (GCW)

    GCW is the actual total for the combination and its load, not a manufacturer’s weight rating.

    Source: CA Commercial Driver Handbook § 3.2.1 Definitions You Should Know ↗

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California / CDL

General Knowledge · 150 questions

California CDL General Knowledge Practice Test

Build your commercial-driving basics with explanations after each answer. Air Brakes, Combination Vehicles and endorsements have separate practice question sets.

Independent knowledge practice, not official DMV exam questions or a substitute for required training.

Choose your CDL knowledge topic

405 questions across 8 topics. Select the areas relevant to your vehicle and endorsements; these are not a required sequence.

Practical skills study guide

Pre-trip inspection, basic controls and road-test preparation. A guide for supervised practice, not a knowledge quiz.