Temporary traffic barriers are primarily installed for which of the following reasons?

Temporary traffic barriers are primarily installed to protect pedestrians from vehicle incursions. This is particularly crucial in areas where work zones intersect with pedestrian pathways, as they help create a safe space for pedestrians, shielding them from the unpredictability of moving traffic. These barriers serve as physical obstacles that deter vehicles from entering pedestrian zones, thereby reducing the risk of accidents and ensuring a safer environment for those on foot.

While other choices mention important aspects of traffic management, their primary focus does not align with the main function of temporary traffic barriers. Increasing traffic flow is a goal of traffic management strategies, but barriers do not directly enhance flow; rather, they may influence how traffic is redirected or managed. Blocking access to construction sites is a related function but is typically more focused on preventing unauthorized entry rather than pedestrian safety. Alerting drivers of speed limits is also vital to traffic safety but is achieved through signage rather than barriers. Hence, the focus on pedestrian protection effectively highlights the critical role that temporary traffic barriers play in enhancing safety during construction or maintenance activities.