What is prohibited concerning objects in vehicles?

The correct answer emphasizes the importance of safety and liability within the operation of vehicles, especially in a fire department context. Prohibiting objects that protrude from trunks or windows is crucial because such items can pose serious hazards during emergency responses. Objects sticking out can obstruct views, especially for other drivers, and can be at risk of becoming dislodged while the vehicle is in motion, potentially causing accidents or endangering personnel.

By ensuring that no items extend beyond the confines of the vehicle, the department maintains a higher level of safety for both its personnel and the public. This aligns with standard safety practices aimed at preventing injuries and ensuring that emergency vehicles can move swiftly and efficiently without obstruction or distraction.

The other options highlight important considerations in vehicle safety, such as visibility and weight, but do not specifically address the immediate danger of items protruding and the implications it carries for operational effectiveness and safety.