Why are toe boards installed around the base of guard rails in elevated work areas?

Toe boards are installed around the base of guard rails in elevated work areas primarily for protection from falling tools or objects. Their purpose is to create a barrier that prevents small items, such as tools or materials, from inadvertently rolling over the edge of the elevated surface. This is particularly important in construction and maintenance environments where the risk of items falling can pose significant safety hazards to workers below. By keeping these items contained within the confines of the working area, toe boards help to ensure the safety of personnel and mitigate the potential for accidents related to falling objects.

While the other options touch on important safety aspects, they do not directly address the primary function of toe boards. Stability and visibility of guard rails may be enhanced by other design features, and preventing unauthorized access is more commonly managed through different means such as barriers or signage. The specific role of toe boards is crucial in maintaining a safe working environment at height.