You are driving a motor vehicle with a manual gearbox. What is the correct thing to do when you see this traffic sign?

This warning sign indicates a steep downhill gradient (here: 12%). On a long or steep descent you should not rely mainly on the foot brake, because continuous braking can overheat the brakes and greatly reduce braking performance (“brake fade”).

That’s why answer 1 is correct: if necessary you shift down to a lower gear before or at the start of the descent so the engine helps to slow the car (engine braking). A good rule of thumb is: choose a gear for going downhill that would also be suitable for driving up the same slope. This keeps your speed under control and protects the brakes.