What are channeling devices primarily used for?

Channeling devices are primarily used to alert drivers of unusual conditions on the road. These devices, which can include cones, barrels, or signs, are strategically placed to guide drivers and inform them of changes in traffic patterns, hazards, or road conditions. Their design and placement are crucial for enhancing safety by making drivers aware of situations that may require caution or a change in behavior, such as construction zones or accident areas.

While other options mention important traffic management concepts, they do not accurately reflect the primary function of channeling devices. For example, blocking traffic completely is not the goal but rather a temporary measure that may occur when channeling devices are used to divert traffic through a safer route. Assigning lanes or providing speed limit information are also key traffic management functions, but they deal more with directing traffic flow and regulation rather than specifically alerting drivers to current unusual conditions as channeling devices do.