What shall be used to protect pedestrians from thrown objects from passing vehicles?

The use of plywood walls is effective in protecting pedestrians from thrown objects from passing vehicles due to their lightweight and portable nature. Plywood walls can be quickly and easily erected in work zones or areas where pedestrian safety is a concern. They serve as a barrier to minimize the risk of debris or objects being dislodged and striking pedestrians.

Plywood is also a cost-effective solution compared to more permanent structures. It can conform to various site conditions and is suitable for temporary installations, which is often important in maintenance of traffic scenarios. This flexibility allows for adjustments as needed based on the work zone layout, ensuring compliance with safety regulations.

Other barriers, while they may also provide some level of protection, may not be as practical or effective in temporary situations. For instance, retaining walls and concrete walls typically represent more permanent structures, which may not offer the same level of adaptability. Traffic barriers are designed primarily for vehicle containment and channelization, not specifically for pedestrian protection from thrown objects. Thus, plywood walls stand out as the most suitable option in the context of protecting pedestrians in environments where work is being conducted near roadways.