What is a major warning sign that a driver may be drowsy?

Difficulty concentrating is a major warning sign that a driver may be drowsy because it indicates that the driver is not fully attentive to the road and their surroundings. When someone is tired, their cognitive functions, including focus, judgment, and reaction times, are compromised. A driver who struggles to concentrate may miss important visual cues, such as traffic signals or pedestrians, and may have slower reflexes, increasing the risk of an accident. Recognizing this sign is crucial, as it suggests that the driver may need to take a break or rest, as continuing to drive in such a state can lead to dangerous situations.

Frequent lane changes, talking with passengers, and exceeding speed limits are behaviors that may indicate distraction or impatience, but they do not specifically highlight the drowsiness aspect as clearly as difficulty concentrating does. These other behaviors could be caused by various factors unrelated to fatigue, making them less reliable indicators of a driver’s drowsiness.