Which sense is primarily affected by fatigue?

Fatigue primarily affects vision due to the increased difficulty in focusing and processing visual information as a person becomes more tired. When a driver is fatigued, their eyes may struggle to adjust to varying light conditions, leading to impaired depth perception, tunnel vision, or difficulty seeing clearly, particularly at night. These problems can significantly impact safe vehicle operation, as the ability to perceive road signs, other vehicles, and potential hazards diminishes.

While other senses can be affected by fatigue, the impact on vision is often the most pronounced and dangerous, making it critical for drivers to recognize signs of fatigue and take measures to ensure their alertness when operating a vehicle.