What do anti-lock braking systems primarily do?

Anti-lock braking systems (ABS) are primarily designed to prevent the wheels from locking up during hard braking. When a driver applies the brakes forcefully, especially on slippery surfaces, traditional brakes can cause the wheels to lock, leading to a loss of steering control. ABS works by automatically modulating the brake pressure to ensure that the tires maintain traction with the road surface, allowing the driver to steer while braking. This control significantly enhances vehicle stability and safety during emergency stops, making it a vital feature for school buses, which carry precious cargo.

The other choices do not accurately reflect the primary function of ABS. While quicker stops may occur as a side benefit of better control with ABS, this is not its main purpose. Additionally, ABS does not provide additional power to the brakes or increase fuel efficiency; its sole focus is on maintaining traction and preventing wheel lock-up during braking.