Final answer:
CMBS applies light braking in the Alert stage to reduce the severity of a potential collision. If you don't respond, CMBS will automatically engage the brakes to try and avoid or mitigate the collision.
Step-by-step explanation:
The action stage in which CMBS (Collision Mitigation Braking System) begins to apply light braking is the Alert stage.
During this stage, the system detects a potential collision and alerts the driver by issuing visual and auditory warnings. If the driver doesn't take action, CMBS initiates light braking to reduce the severity of the impact.
For example, let's say you're driving a car equipped with CMBS, and the system detects a cyclist suddenly crossing your path.
The system will first alert you, giving you a chance to react and apply the brakes.
If you don't respond, CMBS will automatically engage the brakes to try and avoid or mitigate the collision.