This CDL practice test is a great place to start if you’re after the TN Combination Vehicles endorsement. Each of the 25 questions is based on the official 2019 CDL manual. The test is designed to prepare you for the Combination Vehicles portion of your 2019 Commercial Driver’s License exam. There are several answer options, but only one of them is correct. Every time you answer a question, you’ll get immediate feedback with a detailed explanation, so you won’t need to wait until the end of the test to know the correct answers.