When starting to move a loaded tractor-trailer, which gear should the vehicle be put in?

When starting to move a loaded tractor-trailer, the vehicle should be put in the lowest available gear. This is essential for several reasons.

First, a low gear provides maximum torque, which is necessary for overcoming the initial inertia of a heavy load. When starting from a complete stop, especially when the vehicle is fully loaded, the engine needs to generate sufficient power to move the weight forward. Using a low gear allows the engine to deliver that power more effectively.

Additionally, starting in a low gear helps to maintain control of the vehicle. It minimizes the risk of stalling the engine and allows the driver to better manage the vehicle's speed and responsiveness, especially when navigating from a standstill on an incline or in challenging conditions, such as slippery roads.

Choosing a higher gear, neutral gear, or overdrive gear would not be appropriate. High gears are designed for efficient cruising at higher speeds, not for starting. A neutral gear would disengage the engine from the drive wheels, which is not suitable for initiating movement. Overdrive gears are intended for fuel-efficient highway travel, and using them to start would risk stalling the engine and create a safety hazard.