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View All PlansIf you already hold a Class A CDL and want to legally operate double or triple trailer combinations, you’ll need to pass the Doubles/Triples Knowledge Test. Successfully passing this test adds the T Endorsement to your Class A CDL. Passing the test is no small feat. The official South Carolina exam consists of 20 multiple-choice questions, and you must answer at least 16 (80%) correctly to pass. If you don’t pass, the South Carolina DMV requires a minimum one-business-day waiting period before you can try again. After three unsuccessful attempts, additional fees may apply.
With only four allowed incorrect answers on the test, you’ll want to use our South Carolina CDL Doubles/Triples Practice Tests, which are designed to mirror the real DMV format. With real-time feedback, in-question hints, and AI-powered learning tools, we make your preparation faster, smarter, and much more effective than traditional study guides you may find elsewhere.
All questions are based on the latest South Carolina CDL Manual, covering safety topics like coupling and uncoupling of trailers, prevention of jackknifing and rollovers, avoidance of the “crack-the-whip” effect, maintaining safe following distances, proper braking techniques in long combination vehicles, and inspection checklists for all trailers.
Obtaining the T endorsement makes you more competitive and adds further value to your CDL, opening the door to new and potentially higher-paying jobs. With major transportation routes like I-20, I-26, I-77, and I-95, and major hubs in Columbia, Charleston, Greenville, and Spartanburg, drivers with double/triple trailer certifications are in high demand. Top employers such as FedEx Freight, XPO Logistics, and Swift Transportation frequently seek drivers with T Endorsements in the state.
Because most double and triple trailer combinations operate with air brakes, you’ll also need to pass the Air Brakes Knowledge Test to avoid a restriction code (“L” or “Z”) on your CDL. This is necessary, not only for doubles/triples but for any vehicles with air brakes. We offer practice tests for this as well as South Carolina-specific practice tests for additional endorsements, including N (Tank Vehicles), H (Hazardous Materials), X (Tank + Hazmat Combo), P (Passenger Vehicles), and S (School Buses).
We have a couple of practice tests for doubles/triples, but don’t stop there. Check out all of our South Carolina-specific practice tests to confidently pass each official knowledge test, restriction removal test, and certification test!
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Last verified for accuracy: November 2025 (reviewed weekly)
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