2026 California CDL (Commercial Driver’s License) Knowledge Test,

The 2026 exam includes updated federal standards for Automatic Emergency Braking (AEB) and California-specific laws like the "Move Over" expansion and Daylighting.

🚛 California CDL 2026: Top 50 Questions & Answers
New 2026 Laws & Penalties
Q: What is the new "Move Over" law expansion for 2026?

A: You must slow down or change lanes for any stationary vehicle with flashing hazard lights, not just emergency rigs.

Q: What is the CDL BAC limit in California?

A: 0.04%. (Driving a personal vehicle with 0.08% also results in CDL disqualification).

Q: How many points is a "Following Too Closely" conviction for a CA CDL holder?

A: 1.5 points (monitored by both the DMV and FMCSA's CSA system).

Q: What happens if you get two "Serious Violations" in 3 years?

A: A mandatory 60-day disqualification.

Q: What is the penalty for a 1st DUI conviction in a CMV?

A: 1-year disqualification (3 years if hauling HazMat).

Q: Does California allow "Traffic School" for CDL holders?

A: Yes, but only for violations in a personal vehicle, and the conviction still appears on your commercial record.

Q: What is the fine for obscuring a license plate in 2026?

A: $1,000 (Infraction AB 1085).

Q: How often must a CDL holder provide a medical certificate?

A: Every 2 years (more often if specified by a doctor).

Q: Within how many days must you report a traffic conviction to your employer?

A: 30 days.

Q: What is the 2026 "Daylighting" rule for commercial parking?

A: No parking within 20 feet of any crosswalk—critical for urban deliveries.

Air Brakes & Mechanical (Must-Know)
Q: At what PSI must the low air pressure warning activate?

A: Before pressure falls below 60 PSI.

Q: What happens when air pressure drops to 20–45 PSI?

A: The spring brakes (emergency brakes) pop out and apply automatically.

Q: What is the maximum leakage rate for a triple combination vehicle (engine off, brakes on)?

A: No more than 6 PSI per minute.

Q: Why should you not use the trailer hand valve while driving?

A: It can cause a trailer skid or jackknife.

Q: What is the minimum tread depth for front tires?

A: 4/32 inch.

Q: What is the minimum tread depth for all other tires?

A: 2/32 inch.

Q: How do you test the air compressor governor?

A: Build pressure to the "cut-out" (approx. 125 PSI) and pump brakes to "cut-in" (approx. 100 PSI).

Q: What does a "S-cam" do?

A: It forces the brake shoes away from each other and against the inside of the brake drum.

Q: What is a dual air brake system?

A: Two separate air brake systems that use a single set of brake controls.

Q: When should you drain your air tanks?

A: At the end of every working day to remove moisture and oil.

Safe Operation & Hazards
Q: How far ahead should you look while driving?

A: 12 to 15 seconds (about 1/4 mile on the highway).

Q: What is the "Stab Braking" technique?

A: Apply brakes all the way until wheels lock, release, then re-apply when wheels roll (only for non-ABS).

Q: What should you do if your vehicle begins to hydroplane?

A: Release the accelerator; do not hit the brakes.

Q: When driving in mountains, what determines your "safe speed" for a downgrade?

A: Weight of the vehicle, length of the grade, steepness, road conditions, and weather.

Q: What is the best way to handle a "Tailgater"?

A: Increase your following distance to the vehicle in front of you.

Q: How much space should you keep in front of you at 40 mph?

A: At least 4 seconds for a 40-foot vehicle.

Q: What is the "Danger Zone" in a school bus?

A: Anywhere within 10 feet of the bus in any direction.

Q: Where should you place reflective triangles on a one-way/divided highway?

A: 10 feet, 100 feet, and 200 feet toward approaching traffic.

Q: What type of fire does a B:C fire extinguisher handle?

A: Electrical fires and burning liquids (gas/oil).

Q: When should you downshift a manual transmission?

A: Before starting down a hill and before entering a curve.

Combination & Cargo
Q: What is the "Trailer Air Supply" control?

A: The red, eight-sided knob used to supply or shut off air to the trailer.

Q: What is "Off-tracking"?

A: When the rear wheels follow a different path than the front wheels during a turn.

Q: How do you check if the trailer is secure after coupling?

A: Gently tug forward with the trailer brakes on.

Q: What is the "Fifth Wheel Skid Plate"?

A: The flat surface that the trailer rests on; it must be well-greased.

Q: What is the most common cause of tire fires?

A: Under-inflated tires or duals that touch.

Q: How often should you check your cargo?

A: Within the first 50 miles, and then every 150 miles or 3 hours.

Q: What is the "Gross Combination Weight Rating" (GCWR)?

A: The value specified by the manufacturer as the loaded weight of a combination vehicle.

Q: Why should you use "Chocks" when parking?

A: To prevent the vehicle from rolling, especially if it doesn't have spring brakes.

Q: What are "Shut-off Valves"?

A: Valves at the back of trailers used to close the air lines.

Q: What is the "Emergency Line"?

A: The air line that supplies air to the trailer tanks and controls the emergency brakes.

California Specifics & Endorsements
Q: In CA, what is the speed limit for a CMV on a two-lane undivided highway?

A: 55 mph.

Q: What lanes are CMVs restricted to in CA?

A: The right-hand lane (or the two right-most lanes on a 4+ lane highway).

Q: What is the "Bridge Formula"?

A: A law that limits weight based on the distance between axles to protect bridges.

Q: Can you use a handheld cell phone while driving a CMV in CA?

A: No. It is a Serious Violation (60-day disqualification for 2nd offense).

Q: What does a "Hazardous Materials" placard look like?

A: Diamond-shaped, placed on all four sides of the vehicle.

Q: When must you stop for a railroad crossing in a CMV?

A: If you are hauling passengers or hazardous materials (must stop 15–50 feet back).

Q: What is "Controlled Braking"?

A: Applying the brakes as hard as you can without locking the wheels.

Q: What is a "Converter Dolly"?

A: An auxiliary axle used to connect a second or third trailer.

Q: What should you do if your trailer begins to skid?

A: Release the brakes to let the wheels grip the road again.

Q: What is the "Kingpin"?

A: The pin at the front of the trailer that locks into the fifth wheel.

Strategy Tip: The 2026 California test has a high failure rate on the Air Brakes section. Pay extra attention to the Leakage Rate numbers and the 3-Step Air Brake Test procedure.