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To drive semi-trucks or tractor-trailers in California, you must obtain a Class A Commercial Driver’s License (CDL), which will allow you to drive any combination of vehicles in which the towed unit has a gross vehicle weight (GVW) or gross vehicle weight rating (GVWR) of over 10,000 pounds.
To practice commercial driving under supervision in pursuit of a CDL, you must obtain a Commercial Learner’s Permit (CLP). But to practice driving tractor-trailers, you must also pass the Combination Vehicles knowledge test. This specialized test will assess how much you know about the theory of operating combination vehicles (such as tractor-trailers). If you haven’t passed the Combination Vehicles knowledge test by the time you obtain a Class A CDL, the CDL will include a restriction prohibiting you from driving combination vehicles.
Have you been studying the official California Commercial Driver Handbook (California CDL Handbook 2026)? You certainly should do so because the questions on both the General Knowledge test and the Combination knowledge test are based on this study guide. However, you’re probably here because you want to get a little more help to pass the Combination Vehicles knowledge test than you’re getting from this handbook. We can help, just as we’ve helped thousands of other aspiring drivers.
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
This free California CDL Combination practice test is based on the official state manual, just like the official knowledge test. It’s up to date as of January, 2026. There are 30 multiple-choice questions and answers on such topics as combination air brake systems, coupling and uncoupling, and pre-trip inspections. Unlike the official knowledge test, this practice test comes with our automated assistant. It can give you a hint if you get stuck on a question and an explanation of the correct answer if you still miss the question.
California can offer numerous economic opportunities to tractor-trailer drivers because of its diverse economy, the largest in the United States. Economic opportunities exist in intermodal transportation at California’s ports and rail hubs, transportation of agricultural products from the Central Valley, transportation of retailers’ products through their distribution networks, and cross-border trade with Mexico.
The most important trucking route is Interstate 5, which runs from the Mexican border in California to the Canadian border in Washington State. Other important Interstate routes include Interstate 10, which is used to transport cargo to Arizona and Texas; Interstate 80, which is used to transport goods from San Francisco eastward; and Interstate 15, for moving cargo from California to Nevada. U.S. Route 101 is an alternative to I-5 for moving goods along the coast.
Routes serving the Central Valley include State Routes 58, 99, and 152.
Driver’s Ed is - nobody wants to set foot inside the DMV. That’s why millions of learners trust us for simple, visual, effective prep.
We are an officially recognized FMCSA Entry-Level Driver Training provider and a proud partner to over 2,500 libraries. We work with safety organizations like GHSA and the National Safety Council to help create safer roads for everyone.
Our trademarked system automatically saves questions you miss, creating personalized tests that target your weak spots until you’ve mastered the material.
Get smarter as you study. Our new AI-powered feedback provides detailed, question-level insights to help you understand the why behind each answer.
Go beyond the boring black-and-white manual. Our interactive handbook lets you read, listen with an MP3 audio version, or even chat with it to find the information you need, faster.
We build our practice questions from the current 2026 CA Driver Handbook and refine them using patterns recent test‑takers report.
Driver handbook • Knowledge‑test/permit overview • Fees & ID requirements • Office/appointment info
We mirror recurring themes (e.g., right‑of‑way traps, sign look‑alikes) and use similar distractors and wording styles.
We don’t collect or publish actual test items and we’re not affiliated with DMV.
