What is the primary function of a portable changeable message sign (PCMS)?

The primary function of a portable changeable message sign (PCMS) is to provide real-time traffic information. This is crucial for informing drivers of current conditions such as accidents, road work, lane closures, or any other pertinent information that could affect their travel. By conveying timely updates, PCMS enhances safety by allowing traffic to adjust accordingly and makes it easier for drivers to navigate changing conditions on the road. This dynamic communication tool is essential for efficient traffic management, especially in construction zones or during incidents that disrupt normal traffic flow.