California CDL General Knowledge Test study guide
California CDL General Knowledge Test · Work through your exam, one topic at a time.
A California commercial driver's license (CDL) is the credential that lets you legally operate a commercial motor vehicle - generally a single vehicle rated 26,001 pounds or more, a combination rated 26,001 pounds or more, a vehicle built for more than ten passengers including the driver, a vehicle towing a trailer rated 10,001 pounds or more, a placarded hazardous materials vehicle, or a 3-axle vehicle weighing more than 6,000 pounds. Before the skills test, applicants must hold a commercial learner's permit (CLP) for at least 14 days, and the CLP itself is issued only after the required knowledge test or tests are passed. The California CDL General Knowledge Test study guide has 5 sections and about 2,379 words.
01Driving Safely: Space, Speed, and Control
Almost every Driving Safely question reduces to one idea: a heavy vehicle needs far more room to stop than a car, and the room required grows with speed. Scan 12–15 seconds ahead, and remember that 15 seconds is a much longer stretch of road at 55 mph than at 25 mph.
342 words, about 2 min02Transporting Cargo Safely
Cargo questions are really weight-and-balance questions. You must stay under the gross vehicle weight rating (GVWR), the gross combination weight rating (GCWR) if you tow, and the limit for each axle.
333 words, about 2 min03Vehicle Inspection and Basic Control
A pre-trip inspection must be systematic, not random. Walk around the vehicle the same way every time: overall overview and leaks, engine compartment (fluids, belts, hoses, steering), lights and reflectors, brake system and air pressure buildup, suspension and steering components, tires and wheels, then coupling devices and trailer.
355 words, about 2 min04Hazard Perception and Emergency Procedures
Hazard perception is about buying time. Scan 12–15 seconds ahead, check mirrors frequently, and look for the cues that predict trouble: brake lights far ahead, a lane closing, workers on the shoulder, pedestrians stepping off a curb, or a vehicle drifting in its lane.
344 words, about 2 min05Vehicle Systems, Hours of Service, and Non-Driving Activities
The compressor charges the tanks; the governor cuts the compressor out near 125 psi and back in near 100 psi. A safety valve protects the system around 150 psi.
1,005 words, about 5 min