Which of the following is a common sign of driver fatigue?

Frequent yawning is a clear indication of driver fatigue. It is a physiological response of the body that often occurs when someone is feeling tired or drowsy. Yawning can signal a lack of adequate sleep or mental exhaustion, which can significantly impair a driver's concentration and reaction times.

When a driver is fatigued, they may struggle to maintain focus and could experience difficulties in staying alert. Consequently, behaviors commonly associated with fatigue, like yawning, can serve as vital warnings for when it's time to take a break or find a safe place to rest. Recognizing these signs is essential for promoting road safety and preventing accidents caused by drowsy driving.