When are drivers most vulnerable to distractions?

Drivers are most vulnerable to distractions when they are tired because fatigue significantly impairs cognitive functions and reaction times. When a driver is tired, their attention may wane, making it harder to focus on the road and increasing the likelihood of being distracted by external factors or internal thoughts. A tired driver might find it difficult to process information, anticipate potential hazards, or respond promptly to changing traffic conditions, all of which can lead to unsafe driving behaviors.

In contrast, busy traffic can also heighten distractions, but drivers may be more alert due to the need for constant engagement. Familiar areas might lead to complacency, where drivers may think they know the route well enough to let their guard down, increasing the risk of distraction. Poor weather certainly requires more attention and caution, but it doesn't specifically pertain to the state of the driver’s alertness or mental focus, which is most affected by fatigue.