What defines yaw marks made by tires?

Yaw marks are a crucial aspect of accident reconstruction and vehicle dynamics. They occur when a vehicle turns sharply and its tires lose traction, resulting in lateral sliding. In this case, option B correctly identifies that yaw marks are created by tires that are freely rotating while simultaneously sliding due to this loss of grip. This phenomenon happens during maneuvers such as cornering or when a vehicle skids, allowing for an assessment of the vehicle's path and behavior prior to the incident.

The other choices do not accurately describe yaw marks: The first option suggests that yaw marks are straight and uniform, which contradicts their typical appearance characterized by their curving nature when viewed on the pavement. The third option implies that yaw marks are linked exclusively to rapid acceleration, which misrepresents their actual formation during lateral sliding rather than forward acceleration. Lastly, stating that yaw marks are always straight directly conflicts with their inherent nature, as they represent a vehicle's loss of control rather than its controlled movement. Therefore, option B is the only accurate definition of yaw marks, emphasizing their formation through the combination of rotation and sliding.