Which of the following is a danger signal of drowsy driving?

The selected answer highlights a critical warning sign of drowsy driving. When a driver’s eyes close or go out of focus, it indicates that they may be falling asleep or losing their ability to concentrate on the road. This loss of focus is particularly dangerous as it significantly impairs reaction times and decision-making, both of which are essential for safe driving. Recognizing this signal can be life-saving, prompting the driver to take necessary precautions, such as stopping for a break or switching drivers if possible.

The other options, while they may reflect certain states or conditions while driving, do not accurately serve as immediate danger signals for drowsy driving. Increased radio volume could be an attempt to stay alert but does not indicate drowsiness itself. Feeling overly energetic is the opposite of what one would expect with drowsy driving, as it suggests high alertness rather than fatigue. A quickly draining phone battery may not have any direct correlation with a driver's state of alertness and therefore is not a valid indicator of drowsiness on the road. Understanding these distinctions can help drivers recognize the signs of drowsy driving and take appropriate actions to enhance their safety and that of others on the road.