Which factor extends driving time beyond legal limits?

Driver fatigue is a significant factor that can extend driving time beyond legal limits because it impacts a driver's ability to operate the vehicle safely and effectively. When a driver is fatigued, they may not be able to maintain the level of alertness needed to respond to traffic situations, which can lead to longer travel times. A fatigued driver might take longer to make decisions, react to stimuli, or be tempted to push past legal hours to reach their destination, compromising their safety and the safety of others on the road.

While factors like traffic conditions can cause delays, they do not necessarily compel a driver to exceed legal driving limits in the same way fatigue does. Unfamiliar routes may lead to slower driving due to the need for careful navigation, but they don't inherently create the same urgency as fatigue. Emergency situations, while they may require quick action, typically dictate a clear necessity for safe and responsible driving rather than extending driving times beyond legal limits. Thus, driver fatigue stands out as the primary reason that could lead a driver to exceed those limits, emphasizing the importance of managing rest and awareness during driving responsibilities.