For a skid mark to occur, what is true about the tire?

A skid mark occurs when a tire is locked and not rotating, leading to friction between the tire and the road surface. This friction causes the tire to slide along the pavement without rotating, leaving a mark of rubber on the road. Locking typically happens during hard braking when a driver applies excessive force to the brake pedal, completely stopping the tire's rotation while the vehicle continues to move forward.

Understanding the dynamics of tire motion is crucial for accident reconstruction and vehicle dynamics analysis. In cases where the tire is rotating at a high speed, it would generally not leave a skid mark but rather a series of tire marks, as the rotation allows for normal rolling friction rather than sliding. Similarly, a tire that is half-locked and spinning or moving in a straight line would not result in a pure skid mark, as there might be some rotational movement preventing the tire from sliding completely across the surface.