What topics are covered on the CDL Combination Vehicles test?

The CDL Combination Vehicles test covers coupling and uncoupling procedures, braking system operation, trailer swing prevention, rollover avoidance, pre-trip inspection, and load securement — all based on Chapter 6 of the FMCSA CDL manual.

What score do I need to pass the CDL Combination Vehicles written test?

Requirements vary by state, but most states require an 80% or higher to pass any CDL knowledge test. We recommend scoring 90% or above on practice tests before taking the real exam.

CDL Combination Vehicles Practice Test 1 (20 Questions with Explanations)

CDL Combination Vehicles · Practice Test 1

20 Questions · Bilingual Explanations

This CDL Combination Vehicles practice test covers the most frequently tested topics, including coupling and uncoupling procedures, trailer swing prevention, and braking systems and load distribution — all aligned with Chapter 6 of the official FMCSA CDL manual.

Click any question number to view the full explanation. We recommend working through them in order and aiming for 90% or higher before scheduling your CDL permit test.

Coupling & Uncoupling Trailer Swing Braking Systems Pre-Trip Inspection Load Distribution Rollover Prevention

About the CDL Combination Vehicles Knowledge Test

The CDL Combination Vehicles endorsement is required to operate semi-trucks, double trailers, and other combination vehicles. The written test is based on Chapter 6 of the FMCSA Commercial Driver's License Standards (49 CFR Part 383) and focuses on six core topic areas:

Coupling & Uncoupling: Step-by-step procedures for properly connecting and disconnecting fifth wheels and trailers
Trailer Swing / Crack-the-Whip Effect: Causes of trailer loss of control during sharp turns or emergency stops, and how to prevent it
Braking Systems: Air brake coordination, brake lag, and how anti-lock braking systems (ABS) work on combination vehicles
Load Distribution: Cargo center of gravity, vehicle stability, and axle weight compliance
Rollover Prevention: Identifying risks from speeding through curves and cargo shifts that can cause a rollover
Pre-Trip Inspection: Safety inspection items specific to combination vehicles

This 20-question practice test mirrors the real exam's topic distribution. Every question includes a detailed explanation and a reference to the relevant section of the CDL manual — ideal for first-time applicants and those retaking the test.