What is the purpose of glad hands in a combination vehicle?

Answer: B — To connect air hoses between trailers

The purpose of glad hands in a combination vehicle is to connect air hoses between trailers. Glad hands are specialized couplings used to link the air brake system of the tractor with the brakes of the trailer(s). When a tractor-trailer combination is hooked up, these fittings ensure that compressed air can flow from the tractor to activate the brakes on the trailer(s). This connection is crucial for the safe operation of a combination vehicle because it ensures that the brakes on all parts of the unit function effectively and in unison. Understanding the role of glad hands is essential for maintaining the braking system's integrity and safety, as any failure in this connection could lead to brake malfunctions, which can pose significant risks on the road.