What does a skid mark indicate about a tire's movement?

A skid mark is a visible mark left on the road surface when a tire slides over it, indicating that the tire has lost traction. This loss of traction usually occurs when the brake is applied forcefully, causing the tire to stop rolling and instead "lock" in place as it slides. When a tire is locked and not rolling, it creates a mark on the road, giving clear evidence of skidding. This phenomenon often leads to the understanding that the vehicle was unable to maintain control.

In contrast, other scenarios such as moving smoothly, hydroplaning, or turning sharply do not typically result in the creation of skid marks in the same manner. A smoothly moving tire keeps rolling without losing grip, while hydroplaning involves a tire riding on a layer of water rather than skidding; neither would produce a locked tire mark. A sharply turning tire may create other types of tire marks, but the defining characteristic of a skid mark is the result of a tire that is locked and not rolling, which is why this answer is the most accurate.