What is the primary reason excessive cargo can be unsafe?

Excessive cargo can be unsafe primarily because it obstructs your vision while driving. When the cargo is piled too high or is improperly secured, it can limit the driver's ability to see clearly in all directions, including mirrors and blind spots. This obstruction can lead to dangerous situations where the driver might not be aware of other vehicles, pedestrians, or obstacles in their path. Maintaining clear visibility is crucial for making safe driving decisions and ensuring the ability to react quickly to changing road conditions.

The other factors, such as the potential for cargo to fall out or creating risks of overloading, are significant concerns but do not directly relate to the immediate safety implications of obstructing vision while driving. The risk of overloading can affect vehicle stability and braking, while limited speed affects overall driving tempo; however, these issues may not be as directly tied to the moment-to-moment safety impact as vision obstruction is.