What is the main action to take when experiencing brake failure?

When experiencing brake failure, downshifting and applying the parking brake is a critical action that can help regain control of the vehicle and bring it to a safe stop. Downshifting reduces the vehicle's speed by utilizing the engine's braking capability, which can slow the vehicle down more effectively than relying solely on coasting. Applying the parking brake can serve as an additional measure to slow the vehicle; however, it should be done cautiously to avoid skidding or losing control, especially if the vehicle is traveling at high speeds.

The combination of these actions allows for a more systematic approach to managing a potentially dangerous situation, helping to mitigate the risks associated with brake failure. This response addresses the immediate need to reduce speed and maintain control, focusing on ensuring safety for the driver and others on the road.