When the **foot brake fails** while driving at 100 km/h, it is important to know how to stop the vehicle safely. The best way to do this is by **shifting to lower gears** and, finally, using the **handbrake**.

- **Downshifting**: By shifting to lower gears, the engine helps to reduce the vehicle's speed. This is because the engine acts as a brake, which is known as "engine braking." It is an effective technique to control speed without relying on the foot brake.

- **Using the handbrake**: Once the speed has decreased sufficiently, the handbrake can be used to bring the vehicle to a complete stop. It is important to **pull the handbrake lever gently** to avoid locking the wheels and losing control of the vehicle.

This combination of techniques allows for a controlled and safe stop when the foot brake is not functioning.