If your brakes fail while driving, stay calm and avoid sudden movements. Gradually release the accelerator and try to gently apply the brakes multiple times to build brake fluid pressure. Use the engine braking by downshifting gears to reduce speed. If possible, use the emergency or parking brake carefully to slow down. Steer the vehicle to a safe area off the road and turn on hazard lights. Contact roadside assistance immediately for professional help. Regular brake maintenance and timely replacement of brake pads and fluid can prevent such emergencies.