Commercial Driver’s License (CDL) HW Practice Test 2026 - Free CDL Practice Questions and Study Guide

Pressing the start button is the action that actually cranks the engine in a truck equipped with a starter button. The starter button is the control that engages the starter motor and begins the engine turning over. The other options don’t start the engine: cruise control is used to maintain speed after you’re moving, engine brake is for slowing or holding the vehicle using the engine, and a clutch-related control isn’t the standard starter input on most trucks. In practice, you’ll also ensure the transmission is in the proper state (Park/Neutral and, depending on the setup, your foot on the brake or clutch), but the act that starts the engine is pressing the starter button.