CDL practice from the official handbooks — every answer explained, every claim cited to the page. 629 questions. All 50 states. Works offline in the cab.
A real question from the app
Each explanation names the handbook section and page it came from. Think we are wrong? Open the book — then tell us.
We read all 51 official handbooks. 36 states publish rules of their own; those questions carry your state's tag. The rest publish the federal manual unchanged, and we say so instead of implying more.
Every number here is generated from what actually ships. We would rather quote a smaller true figure than a rounder false one.
Correct question counts, a clock, flagging, an answer sheet you can jump around, and the same pass mark the DMV applies. An easier bar teaches the wrong sense of ready.
Everything you get wrong collects in one place — explanation and citation included. Fix them, then rebook.
Plain-English guides for all 6 tests, plus a cheatsheet of every figure the exam asks for and a walkthrough of the licensing process itself.
Everything ships inside the app. Yard, cab, waiting room. Progress stays on your device — we do not operate a server that could receive it.
The test every applicant takes.
Trucks with air brakes.
Pulling a trailer.
Hazardous loads.
Liquid and gas loads.
Two or three trailers.
Start preparing today. Complete General Knowledge exam with official state handbook citations is 100% free. No subscriptions, no trials.
Everything you need to know about the CDL written exam, state requirements, endorsements, and pass marks.
CDL Prep: All 50 States is designed specifically around official state commercial driver manuals and federal FMCSA regulations. Unlike generic national apps that teach federal rules that fail students in state-specific exams, CDL Prep covers all 50 states plus DC. 36 states publish statutes of their own (such as California's 55 mph towing law or Texas special vehicle rules), and we write questions from them with exact handbook page citations. The app features timed mock exams scored at the real 80% pass mark and works 100% offline with no subscriptions.
Yes. The entire General Knowledge test bank — the mandatory exam every commercial driver must pass — is 100% free with all handbook page citations, detailed explanations, and exam simulations included. Additional endorsement banks (Air Brakes, Combination, HazMat, Tanker, Doubles & Triples) unlock with a single one-time purchase. There are no subscriptions, no auto-renewing trials, and no countdown timers.
No, and be cautious of any app claiming to offer 'real DMV exam questions'. Official state DMV question pools are confidential and rotated frequently. Our questions are written directly from the official state driver handbooks and FMCSA knowledge requirements that DMVs draw the real exam from. Every single answer cites the handbook section and page number so you can verify it yourself.
Yes. While federal regulations (49 CFR Part 383) set baseline knowledge standards, individual states enforce their own laws. 36 states publish local statutes of their own (such as speed limits, right-of-way, and unique state endorsements). The other 15 publish the federal manual unchanged. CDL Prep clearly tags every question as either Federal or State-Specific so you never study the wrong rule.
80 percent, on every knowledge test, in every US state. On a standard 50-question General Knowledge exam, you must answer at least 40 questions correctly (allowing a maximum of 10 wrong). On a 25-question Air Brakes exam, you must answer at least 20 correctly (allowing 5 wrong). All practice tests in CDL Prep use these exact state test lengths and passing marks.
Test lengths vary by endorsement: General Knowledge typically has 50 questions; Air Brakes has 25; Hazardous Materials (HazMat) has 30; Combination Vehicles has 20; Tanker has 20; and Doubles & Triples has 20. The mock exams in CDL Prep match these exact question counts and timed conditions.
To earn a Class A Commercial Learner's Permit (CLP), applicants must pass three core written knowledge tests: 1) General Knowledge, 2) Air Brakes, and 3) Combination Vehicles. Depending on the equipment you plan to drive, you may also add endorsements such as HazMat (H), Tanker (N), or Doubles & Triples (T).
Federal regulation (49 CFR § 383.25) mandates that you must hold your Commercial Learner's Permit (CLP) for a minimum of 14 days before taking the behind-the-wheel CDL skills test. This 14-day mandatory waiting period applies in all 50 states and cannot be waived, even if you are upgrading license classes or adding a skills-tested endorsement.
Entry-Level Driver Training (ELDT) is federally required under 49 CFR Part 380 for all first-time Class A or Class B CDL applicants, passenger/school bus endorsements, and HazMat endorsements. Training must be completed with an approved provider listed on the FMCSA Training Provider Registry (TPR). Note: for a first-time HazMat endorsement, ELDT theory training must be completed and recorded in the registry before you sit the state HazMat knowledge test at the DMV.
Yes, if you plan to drive any vehicle equipped with air brakes. Skipping the Air Brakes knowledge test places an 'L' restriction (Air Brakes restriction) on your commercial license, legally barring you from operating the vast majority of commercial tractor-trailers.
The CDL exam tests three critical air pressure thresholds: 1) The Low Air Pressure Warning buzzer/light must activate before tank pressure drops below 55 psi (typically between 60–75 psi). 2) The emergency Spring Brakes must pop out and apply automatically between 20 and 45 psi. 3) The air compressor governor cut-out pressure is 120–140 psi (cut-in around 100 psi). Confusing the 55 psi warning with the 20–45 psi spring brake activation is the single most common mistake on the Air Brakes test.
To obtain a HazMat (H) endorsement, you must: 1) Complete approved FMCSA ELDT HazMat theory training, 2) Pass the TSA Security Threat Assessment background check and fingerprinting, and 3) Pass the state DMV HazMat written knowledge exam (30 questions, 80% passing grade).
Retake waiting periods, fees, and attempt limits are determined by each state's DMV. Most states allow up to 3 attempts within the 180-day application period before requiring a reapplication fee. CDL Prep includes a dedicated Mistakes Review mode that automatically collects questions you missed so you can drill weak spots before rebooking.
Yes. The entire question bank, handbook citations, diagrams, and study materials ship directly inside the app. It works seamlessly in truck cabs, rural depots, or DMV waiting rooms without cellular signal or Wi-Fi. Your test history stays stored locally on your device.
M4 Infotech. You can reach our team at support@m4infotech.com for product questions, feedback, or handbook rule clarifications.
CDL Prep is available for iOS on the Apple App Store and for Android on Google Play.
