What should a driver do if they experience brake failure while driving?

In the situation of brake failure, the most appropriate action for a driver to take is to utilize the emergency brake as a way to regain control of the vehicle and slow down. The emergency brake, or handbrake, is designed as a backup system to help bring the vehicle to a stop in situations where the regular brakes are compromised. By engaging the emergency brake, the driver can apply more gradual force to the brake system compared to an immediate full application of brakes, which could lead to skidding or loss of control.

Effectively, the emergency brake operates independently of the primary braking system, making it a crucial tool during brake failure scenarios. By using it appropriately, the driver increases their chances of safely bringing the vehicle to a stop without further endangering themselves or others on the road.

When considering the other options, accelerating to maintain momentum would be exceedingly dangerous because it would increase speed and reduce control during a critical situation. Shifting to a lower gear may help slow down the vehicle through engine braking, but it is not as effective as immediately engaging the emergency brake. Calling for roadside assistance while driving is not a viable solution as it does not address the immediate need for stopping the vehicle, which is crucial in a brake failure situation.