What is the primary function of an Anti-lock Braking System (ABS) during emergency braking?

1. It prevents wheel lockup, allowing the driver to maintain directional steering control while braking heavily
2. It automatically increases engine horsepower to power out of a skid
3. It eliminates the need for the driver to press the brake pedal
4. It halves the total braking distance on all road surfaces, including deep mud and ice