What are hose couplers (glad hands) used for in tractor/trailer combinations?

Hose couplers, commonly referred to as glad hands, are specifically designed to connect the service and emergency brake airlines of tractor/trailer combinations. This connection is crucial for ensuring that the braking systems of both the tractor and the trailer work in harmony. When the glad hands are properly connected, the brake signals from the tractor can be transmitted to the trailer, enabling effective braking and enhancing overall safety during transport. This ensures that when the driver activates the brakes, both the tractor and trailer respond appropriately, allowing for safe stopping and maneuvering of the entire combined vehicle.

The primary function of the glad hands is related to the pneumatic brake system rather than fuel efficiency, loading and unloading, or vehicle stabilization. While those other factors play significant roles in vehicle operation and safety, the specific and essential role of glad hands is to facilitate the proper functioning of the braking systems in tractor/trailer configurations.