CDL FAQ

A Commercial Driver's License (CDL) is required to operate large commercial vehicles in the United States. You need a CDL if you drive vehicles with a gross vehicle weight rating (GVWR) of 26,001 lbs or more, vehicles designed to transport 16+ passengers (including the driver), or vehicles transporting hazardous materials that require placarding.

Yes — 100% free. Every practice test, ELDT theory course, handbook, and video on CDL Study Buddy is available at no cost. No registration fees, no paywalls, no trials that expire. We support the platform through advertising so that every aspiring truck driver can access quality training materials.

The CDL general knowledge test typically has 50–60 multiple-choice questions, depending on your state. You usually need a score of 80% to pass. Our practice tests for each state mirror the official test format with the same number of questions and passing score requirements.

There are seven CDL endorsements: T — Double/Triple Trailers, P — Passenger Transport, N — Tank Vehicles, H — Hazardous Materials, X — Combination of Tanker and Hazmat, S — School Bus, and W — Tow Truck. Each requires a separate knowledge test, and some (like Hazmat) also require a background check and TSA approval.

Entry-Level Driver Training (ELDT) is an FMCSA requirement that went into effect on February 7, 2022. All new CDL applicants must complete ELDT from a registered training provider before taking their CDL skills test. Our ELDT theory courses are FMCSA-compliant and free — upon completion, we register your training with the FMCSA Training Provider Registry.

Select your state from our practice test page, then choose the endorsement you're studying for (General Knowledge, Air Brakes, Hazmat, etc.). Each state page has tests tailored to that state's specific CDL handbook and requirements, with the correct number of questions and passing score for your DMV exam.

Yes — CDL Study Buddy is fully responsive and works on any device. All practice tests, ELDT courses, handbooks, and videos are accessible from smartphones, tablets, and desktops with no app download required.

The timeline varies by state and individual dedication. With focused study (1–2 hours per day), most people can pass the CDL knowledge test within 2–4 weeks. The ELDT theory courses take about 8–12 hours total. After that, you'll need behind-the-wheel training and to pass your skills test. Total time from start to licensed driver is typically 2–4 months.

Class A allows you to operate combination vehicles (truck + trailer) with a GVWR of 26,001+ lbs where the trailer is over 10,000 lbs — typically semi-trucks and tractor-trailers. Class B covers single vehicles 26,001+ lbs (dump trucks, straight trucks, buses). Class C covers vehicles under 26,001 lbs that transport 16+ passengers or hazardous materials requiring placarding.

No — rental trucks under 26,001 lbs GVWR can be driven with a standard driver's license. Most single-axle rental trucks fall under this limit. However, larger trucks (like 26-foot box trucks) may exceed 26,001 lbs GVWR and require a CDL. Always check the GVWR on the rental agreement before driving.

A DUI conviction can affect your CDL eligibility. Federal law imposes a one-year disqualification for a first DUI conviction while driving any vehicle (not just commercial), and a lifetime disqualification for a second DUI. Some states have stricter rules. However, with time and proper legal guidance, it may still be possible to pursue a CDL — check with your state DMV.

The pre-trip inspection is the first part of the CDL skills test. You must walk around your vehicle and explain to the examiner what you're checking and why. It covers the engine compartment, cab/steering, coupling systems, lights, tires, brakes, and emergency equipment. Our pre-trip inspection guide and practice tests help you master the 7-step inspection process.

We recommend taking a full practice test at the start of your studies to identify weak areas, then focusing your study on those topics. Take another practice test every 3–4 days to track your progress. You're ready for the real exam when you consistently score 85% or higher on multiple practice tests in a row.

Yes — we provide links to official CDL handbooks from all 50 states and DC. These are the same handbooks the DMV uses to write your test, so studying from your state's handbook alongside our practice tests gives you the best preparation. Find your state's handbook on our CDL Handbook page.

You can retake the CDL knowledge test, but state rules vary. Most states require a waiting period of 1 business day before retesting, and some limit how many times you can retest within a certain period. Some states also charge a fee for each retake. Using practice tests to prepare thoroughly can save you time and money.

Yes — our test content is reviewed and updated regularly to reflect current FMCSA regulations and state-specific CDL handbooks. We track regulatory changes and update questions as soon as new handbooks are released. Each page shows the last review date so you know the content is current.

Yes — school bus drivers must hold a CDL with both a Passenger (P) endorsement and a School Bus (S) endorsement. Additional requirements include passing a knowledge test, a skills test in a school bus, a background check, and often a physical exam and drug test. Requirements may vary by state.

To get your CDL permit (Commercial Learner's Permit or CLP), you must pass the CDL general knowledge test at your state DMV. You'll need to provide identification documents, pass a vision test, and pay the permit fee. Most states require you to hold your CLP for at least 14 days before taking the skills test. Study with our practice tests and your state's handbook to prepare.

All CDL holders must pass a DOT physical exam conducted by a certified medical examiner listed on the FMCSA National Registry. The exam covers vision (at least 20/40 in each eye), hearing (able to hear a forced whisper at 5 feet), blood pressure, and overall physical fitness. You must carry your Medical Examiner's Certificate with you while driving.

Yes — our ELDT theory courses are registered with the FMCSA Training Provider Registry. Upon successful completion of a course, we automatically submit your training record to the FMCSA, and it will appear in the TPR database for 1 year. Your training provider or employer can verify your completion through the official FMCSA system.