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California CDL General Knowledge Test Practice Test

The California CDL General Knowledge Test practice page covers core commercial-driving judgment, including vehicle control, hazard response, safe maneuvering, and cargo security. Questions draw on practical situations such as approaching restricted sight lines, entering a freeway, driving in heavy rain, and responding to warning signals or a vehicle fire.

Exam overview

Exam providerCalifornia Department of Motor Vehicles
Exam codeNot listed
CategoryDriver Licensing

About the California CDL General Knowledge Test Exam

Commercial drivers must anticipate how vehicle size, weight, braking systems, road conditions, and surrounding traffic affect safe decisions. Practice scenarios address choosing a cautious speed and following distance, adjusting for wet pavement, and controlling the vehicle near intersections, work zones, and emergency vehicles. Other questions focus on backing with limited visibility, merging from an acceleration lane, confirming adequate air-pressure buildup before moving, and securing cargo to prevent shifting. Downgrade questions involve selecting an appropriate approach when a retarder is available; emergency questions ask about using an onboard fire extinguisher safely. Working through these situations helps connect hazard recognition with the actions a driver may need to take before a risk becomes an emergency.

Sample Practice Questions

Review a selection from this exam's published US Practice Tests practice bank.

Question 1

A driver sees a fire or emergency vehicle approaching from behind with its warning signals activated. What is the appropriate general response?

  1. AMaintain speed so the emergency vehicle can pass on either side.
  2. BStop immediately in the current lane.
  3. CYield by moving to the right side of the road and stopping when safe, as required by law.
  4. DAccelerate to reach the next intersection before it arrives.
Show answerCorrect answer: C

Drivers generally must yield to an emergency vehicle using its warning signals by moving right and stopping when safe, while obeying applicable law and avoiding sudden, unsafe maneuvers.

Question 2

In heavy rain, what is a prudent way to reduce the risk of losing traction?

  1. AReduce speed and increase following distance
  2. BUse cruise control to keep speed constant
  3. CBrake sharply before every curve
  4. DFollow another vehicle more closely to see its path
Show answerCorrect answer: A

Wet roads reduce tire grip and can increase stopping distance. Slowing down and leaving more space allow more time to react and help avoid abrupt maneuvers.

Question 3

A driver is approaching an intersection with limited sight distance. What is a prudent approach?

  1. AIncrease speed so the vehicle spends less time in the intersection
  2. BProceed without checking because cross traffic must yield
  3. CReduce speed as needed and be prepared to stop if the path is not clear
  4. DSound the horn continuously and maintain speed
Show answerCorrect answer: C

Limited visibility means the driver may not be able to confirm that the intersection is clear. Slowing and being prepared to stop allows time to respond to hazards or traffic controls.

Question 4

What is a safe general practice when backing a large vehicle?

  1. ABack quickly so the maneuver takes less time
  2. BRely only on mirrors because getting out to look wastes time
  3. CUse a guide when available, communicate clearly, and stop if unsure
  4. DKeep moving whenever the guide is out of sight
Show answerCorrect answer: C

A guide can help identify hazards that are difficult to see from the cab. If the guide disappears from view or the driver is uncertain, stopping is safer than continuing blindly.

Question 5

When entering a freeway from an acceleration lane, what should a commercial driver do?

  1. AStop at the end of the lane and wait for all traffic to pass
  2. BMatch the speed of traffic when safe and merge into an adequate gap
  3. CEnter immediately at a much lower speed so other drivers can react
  4. DUse the shoulder until a lane becomes completely empty
Show answerCorrect answer: B

Building speed in the acceleration lane and merging into a suitable gap helps the vehicle join traffic smoothly. The driver must yield as needed and avoid forcing other vehicles to brake or swerve.

Question 6

Why should a driver check the vehicle’s air-pressure build-up before moving an air-brake-equipped vehicle?

  1. ATo confirm the system has sufficient air pressure for safe brake operation
  2. BTo warm the engine more quickly
  3. CTo reduce the vehicle’s turning radius
  4. DTo ensure the fuel tank is full
Show answerCorrect answer: A

Air brakes depend on adequate system pressure. A driver should follow the vehicle’s procedures and not operate until pressure is in the required range and warning devices indicate normal operation.

Question 7

A driver is approaching a work zone where workers are present and traffic lanes are narrowed. What is the safest general approach?

  1. AMaintain normal speed until reaching the workers.
  2. BSlow down, watch signs and traffic control, and proceed cautiously.
  3. CMove into a closed lane if it appears clear.
  4. DFollow the vehicle ahead closely to avoid being cut off.
Show answerCorrect answer: B

Work zones can involve changing lane paths, workers, equipment, and sudden stops. Reduce speed as appropriate, follow posted directions, and leave room to respond safely.

How to use this practice test

Access the free practice set to work through up to 20 randomly selected questions from the 50-question bank in a session. Submit your answers to see results, then revisit any missed scenarios and identify whether the decision involved speed, visibility, braking, maneuvering, or cargo safety.

Preparation tips

  • For rain-related scenarios, connect reduced speed and increased following distance with the risk of losing traction; avoid assuming ordinary dry-road spacing is adequate.
  • When studying backing questions, consider how to minimize blind areas, use a spotter when available, and stop if the path cannot be confirmed clear.
  • Review how air-pressure buildup affects readiness to move an air-brake-equipped vehicle, and distinguish a system check from normal service braking.
  • For cargo-security questions, focus on preventing load movement that could affect vehicle balance, steering, or braking.
  • Compare responses to work zones, restricted sight lines, and emergency vehicles by identifying the hazard first and choosing an action that preserves space and control.
Official sourceOfficial exam page ↗