ABS works by detecting individual wheel-lock and momentarily releasing the brakes on that wheel. This decreases the amount of brake fluid supplied to the wheel, allowing it to regain traction.
Anti-lock braking systems were first introduced onto New Zealand roads in the early 1980s and are now standard equipment on most new vehicles.
ABS prevents wheel lock-up and consequent sliding under heavy braking or on slippery road surfaces.
Wheel lock-up causes loss of steering and vehicle control, so ABS allows the driver to steer away from hazards, even on slippery surfaces, while applying maximum braking force.