Which of the following is a warning sign of drowsiness while driving?

Yawning repeatedly is a well-recognized warning sign of drowsiness while driving. When a driver experiences fatigue, the body often responds with yawning as a way to increase oxygen intake and alertness. This physiological response indicates that the driver may not be fully attentive and could be at risk of falling asleep at the wheel, leading to dangerous situations. Recognizing such signs is crucial for maintaining road safety.

The other options do not signify drowsiness. For example, smiling frequently is typically associated with good mood or expression and does not correlate with fatigue. Looking at the GPS is a common driving action, although it could lead to distraction if done too often, it doesn’t directly indicate drowsiness. Similarly, listening to the radio is a normal activity while driving and does not suggest fatigue. Understanding these distinctions helps drivers recognize the importance of staying alert and knowing when to take breaks to ensure their safety and the safety of others on the road.