Final answer:
When needing to slow down, a driver should slow down gradually and use brakes lightly.
Step-by-step explanation:
When needing to slow down, a driver should slow down gradually and use brakes lightly. The action a driver should take when needing to slow down is to slow down gradually and use brakes lightly. Swiftly applying brakes or using the brakes forcefully can cause the car to stop abruptly and potentially lead to loss of control. Depending on engine braking only may not provide enough stopping power in certain situations. By slowing down gradually and using brakes lightly, the driver can maintain better control over the vehicle and ensure a safer deceleration.