Variable Messaging Panels (PMV) are signage panels designed to alert or inform the user about the state of the road. A PMV may display an icon or written messages, which may alternately be displayed on, off, or flashing as required.

PMVs are usually placed on poles overlooking roads, especially on highways. They are dynamic devices that broadcast messages in real time, and must comply with the rules, decrees and regulations in force. These messages can include traffic characteristics, traffic jams, weather conditions, rain-wet asphalt, temperature, and informational messages such as the existence of a radar control.[1]​.

Variable messaging panels can also be used in cities to report on activities and events, in addition to parking availability or traffic congestion.

These characteristics make these panels one of the most used devices on the road.

The panels are made up of four elements: