Glad hands are primarily used for connecting which components in truck-trailer combinations?

Glad hands are specifically designed for connecting the service and emergency air lines between the truck and trailer in combination vehicles. These couplings facilitate the transfer of compressed air necessary for the operation of the trailer's braking system. When a truck is coupled to a trailer, the glad hands ensure that air pressure can be communicated effectively, allowing the driver to control both the service brakes (for regular stopping) and the emergency brakes (as a fail-safe in case of air line failure).

This connection is critical for maintaining the functionality and safety of the trailer's braking systems. Properly functioning glad hands ensure that the air supply is stable and secure, which directly affects the vehicle's stopping power and overall safety on the road. Understanding the role of glad hands within the air brake system is essential for safe operation and compliance with transportation regulations.