ABS: Racing Driver Braking For Us All

ABS brakes save lives every day. Jake Venter explores how these technological marvels work, and why they sometimes don’t.

- Jake Venter

ABS (antilock braking system) brakes are a clever electronic copy of what racing drivers do when they brake hard: they employ cadence braking. In this technique, the brakes are applied hard, then released somewhat to avoid locking the wheels, and applied hard again. Doing this at the correct frequency, in tune with the car’s suspension compliance, helps prevent skidding and ensures the shortest possible stopping distance.

A modern ABS is controlled by an electronic brake control module (EBCM) that receives inputs from wheel speed sensors, a vehicle speed sensor, brake pedal position sensor, yaw rate sensor, steering wheel angle sensor and the hydraulic line pressure sensor. The EBCM calculates hydraulic pressure in the brake fluid distribution lines accordingly. It also shares information with other electronic units that control stability during cornering, wheel spin, brake force distribution, brake assist (which monitors brake pedal speed), hill descent control, trailer brake and hill start assist.

HOW THE ABS OPERATES