What color represents the emergency line in combination vehicles?

In combination vehicles, the emergency line is represented by the color red. This is a standardized color coding system used in the trucking and commercial vehicle industry to ensure clarity and safety when handling braking systems. The emergency line is crucial because it carries the signal for the emergency brakes of the trailing vehicle.

By using red for the emergency line, it helps drivers to quickly identify and differentiate it from other lines, such as the service line (which is typically blue) and the electric line (which may be yellow). This helps in reducing the risk of confusion during coupling and uncoupling, maintenance, or emergency situations. Thus, understanding and recognizing this color coding system is vital for the safe operation of combination vehicles.