California CDL General Knowledge Test cheat sheet

Following distance rule: allow one second for each 10 feet of vehicle length, plus one extra second at speeds above 40 mph. A 60-foot combination at 50 mph needs about 7 seconds.

Total stopping distance = perception distance + reaction distance + brake lag + effective braking distance. It increases with speed, weight, and poor traction.

A loaded tractor-trailer at 55 mph may need 300 feet or more to stop on dry pavement; rain, ice, or worn tires increase that distance.

At 55 mph a vehicle travels about 80 feet per second, so a 3-second gap covers about 240 feet.

Search 12 to 15 seconds ahead in cities and up to a quarter mile ahead on highways to spot hazards and signals early.

Before a lane change, check mirrors and blind spots, signal early, and confirm the trailer has cleared the lane before moving over.

At railroad crossings, slow down, look and listen, and do not stop on the tracks. Certain vehicles carrying passengers or hazmat must stop.

At night, do not overdrive your headlights; drive slowly enough to stop within the lit distance, and use low beams in fog or rain.

Do not exceed the Gross Vehicle Weight Rating, any Gross Axle Weight Rating, tire limits, or state bridge and axle limits.

For most cargo, the combined working load limit of all tiedowns must be at least 50 percent of the cargo weight.

At least two tiedowns are required for most articles; longer cargo needs additional tiedowns to secure each segment.

Inspect cargo and tiedowns within the first 50 miles and every 150 miles or 3 hours afterward, whichever comes first.

Loads that could spill, blow off, or create dust must be covered; cargo must not obscure lights, plates, or the driver's view.

California generally limits vehicle height to 14 feet and width to 8.5 feet without an oversize permit; route restrictions may be lower.

Hazardous materials require proper shipping papers, placards, parking rules, and route restrictions.

Distribute cargo to keep weight balanced; overloading the front or rear axle can reduce steering and braking control.

A pre-trip inspection checks tires, wheels, lights, brakes, fluids, belts, hoses, coupling devices, and cargo securement before driving.

A low-air warning must activate before air pressure drops below 60 psi; spring brakes normally begin to apply between 20 and 45 psi.

After coupling a tractor-trailer, perform a tug test and confirm the fifth-wheel locking jaws are closed around the kingpin.

Back slowly, no faster than a walk, and use a spotter when available; stop if you lose sight of the spotter.

When parking downhill with a curb, set the parking brake, place the transmission in a low gear or park, and turn wheels toward the curb.

Coasting in neutral is prohibited; use the proper gear and avoid riding the clutch or overusing the brakes on long downgrades.

Front tires need at least 4/32 inch tread depth; all other tires need at least 2/32 inch, with no cuts or bulges.

Start heavy vehicles in a low gear and make smooth steering, acceleration, and braking inputs to maintain control.

In a rear-wheel skid, steer in the direction you want the front of the vehicle to go, and avoid hard braking.

Hydroplaning can begin at speeds as low as 30 mph on wet roads; reduce speed and avoid sudden steering or braking.

After a tire blowout, hold the steering wheel firmly, keep the vehicle straight, and slow gradually before leaving the road.

If the brakes fail, downshift, apply the parking brake gradually, and look for an escape ramp or safe runoff area.

For a vehicle fire, stop, shut off the engine, get everyone away, and call emergency services; do not fully open the hood.

At a crash scene, warn traffic, call for help, and do not move injured people unless they are in immediate danger.

In fog, use low beams, slow down, and increase following distance; high beams reflect off the fog and reduce visibility.

Escape ramps use gravel or sand to stop a vehicle with failed brakes; aim for the ramp before speed becomes uncontrollable.

A dual air brake system has two separate circuits, so a failure in one circuit may still leave partial braking capability.

If the ABS warning lamp stays on, the anti-lock feature is not working, although normal brakes usually remain available.

The air compressor governor cuts out near 120 to 125 psi and cuts in near 100 psi; the safety valve releases at about 150 psi.

The air tank safety valve protects the system from overpressure and must not be tampered with or blocked.

If oil pressure drops or the warning light stays on, stop the engine safely; continued driving can destroy the engine.

A coolant temperature gauge in the hot range or a warning light means the engine is overheating and should be checked.

The voltmeter or warning light shows charging system status; a low reading can indicate a failed alternator or loose belt.

The fifth wheel, kingpin, locking jaws, and safety latch must be inspected for wear, cracks, and proper engagement.

After 10 consecutive hours off duty, a property-carrying driver may drive up to 11 hours.

A driver may not drive after the 14th consecutive hour on duty; off-duty breaks do not extend this window.

A 30-minute break is required after 8 cumulative hours of driving without a qualifying interruption.

The weekly limits are 60 hours on duty in 7 days or 70 hours on duty in 8 days.

A 34-hour restart can reset the 60-hour and 70-hour weekly limits when the required rest is taken.

A record of duty status must show duty status, date, time, location, miles driven, and carrier information.

On-duty time includes inspecting, fueling, loading, securing cargo, and other work performed for the carrier.

Driving time is recorded separately from on-duty not-driving time and counts toward the 11-hour driving limit.

A commercial driver is considered over the alcohol limit at 0.04 percent blood alcohol concentration.

Refusing an alcohol or drug test can lead to license suspension, disqualification, and employment consequences.

Commercial drivers may not use a handheld mobile phone while driving; texting is also prohibited.

A current DOT medical examiner's certificate or valid medical qualification on the license record is generally required.

Fatigue slows reaction time and judgment; scheduled rest and breaks are part of safe trip planning.

Drug testing can include pre-employment, random, post-accident, reasonable-suspicion, and return-to-duty tests.

Choose parking areas that are safe, well lit, and away from traffic lanes or ramps when taking rest breaks.

Shipping papers and required permits must be within reach and available for inspection during a trip.