Which of the following is a sign of drowsy driving?

Drifting between lanes is a significant indicator of drowsy driving because it reflects a lack of attention and control over the vehicle. When a driver is drowsy, their reaction times increase, and they may have difficulty maintaining focus on the road. This can lead to unintentional lane changes, which poses a serious safety risk to the driver and others on the road. Drowsiness can impair cognitive functions, making it challenging for the driver to recognize their position in the lane or respond appropriately to road conditions. It is crucial for drivers to be aware of such signs and act accordingly to ensure their safety and the safety of others.

Constantly checking a watch, talking to passengers, and listening to calming music do not necessarily indicate drowsiness. While they might be behaviors associated with fatigue in some contexts, they do not directly reflect impaired driving performance like drifting between lanes does.