What is the primary function of anti-lock brakes?

The primary function of anti-lock brakes (ABS) is to allow the driver to maintain steering control while braking. When a vehicle's wheels start to lock up during hard braking, ABS automatically modulates the brake pressure to prevent the wheels from fully stopping their rotation. This prevents skidding and enables the driver to steer the vehicle effectively, even in emergency braking situations. By allowing the driver to steer, it enhances safety and helps avoid obstacles, which is crucial for maintaining control of the vehicle during potentially dangerous situations.

The other options do not accurately describe the primary function of ABS. While improved fuel efficiency, increased braking speed, and preventing engine stalling are important aspects of vehicle performance, they do not relate to the specific purpose of anti-lock brake systems, which focuses on enhancing control over braking.