What could indicate that a driver is experiencing drowsiness?

The inability to remember the last few miles driven is a significant indicator of drowsiness. This phenomenon is often referred to as "highway hypnosis" or zoning out, where a driver may lose awareness of their surroundings due to fatigue. When a person is drowsy, their attention and cognitive functions are impaired, making it challenging to stay focused on the road. This lack of memory about recently driven distances suggests a lapse in attention, which can occur when someone is struggling to stay alert.

In contrast, the other options reflect behavior or states that are typically not associated with drowsiness. Increased speed and frequent lane changes can indicate aggressive or distracted driving rather than fatigue. Feeling energized is the opposite of drowsiness, suggesting alertness and readiness to drive. Recognizing the signs of drowsiness, such as memory lapses during driving, is crucial for safety and can help prevent accidents caused by fatigued driving.