This occurs when the braking force applied to a wheel exceeds the available traction between the tire and the road surface. The wheel stops spinning and drags across the pavement, eliminating steering control and extending stopping distances. Anti-lock braking systems were developed specifically to detect and prevent this condition by rapidly pulsing the brake pressure.
Heard on the job
The right front wheel went into lockup as soon as he hit the wet patch on the track.
Insider tip
A locked tire provides significantly less stopping power than one that is still turning just at the threshold of losing grip.