Final answer:
If your brakes fail, you should both shift into a lower gear to use engine braking and use the emergency brake to help slow down the vehicle and come to a stop safely.
Step-by-step explanation:
If your brakes fail, it's important to stay calm and take immediate action to safely bring your vehicle to a stop. There are two primary steps you can follow when experiencing brake failure:
- Shift into a lower gear: This will help reduce your speed by using engine braking. As you downshift, the engine's rpm increases, and this helps to slow down the vehicle.
- Use the emergency brake: Also known as the parking brake, it operates separately from the main hydraulic brake system and can help slow the vehicle. Apply the emergency brake slowly to avoid locking up the wheels which can lead to a skid.
Therefore, the correct answer to the question 'If your brakes fail, you should do which of the following?' is Both I and II. You should shift into a lower gear and use the emergency brake to control your vehicle and bring it to a stop.