What is a common warning sign of drowsiness while driving?

Frequent yawning is indeed a common warning sign of drowsiness while driving. Yawning is a physiological response that often occurs when the brain is not receiving enough stimulation or oxygen, which can be indicative of fatigue. When a driver is feeling sleepy or drowsy, their body may signal this state through yawning. This instinctive action serves as a cue that one might need to pull over and rest or take a break to ensure safety on the road. Recognizing these signs is crucial because drowsy driving can impair reaction times, judgment, and overall driving performance, similar to alcohol impairment.

Listening to the radio might keep a driver engaged but is not a definitive indicator of drowsiness. Feeling overly energetic would suggest alertness, which contradicts drowsiness. Constant talking could maintain a level of engagement but does not inherently signal fatigue; in fact, it may even help to stave off drowsiness if done with another passenger. Thus, frequent yawning clearly stands out as a direct response to drowsiness, highlighting the importance of awareness of one's physical state while driving.