What is a Portable Changeable Message Sign?

message boards

A portable changeable message sign (PCMS), also known as a variable message sign, is a traffic control device used to provide motorists with information regarding the roadway or traffic conditions. A PCMS features a large screen that sits on a trailer that is pulled by a truck. These signs are quick to set up and work well in temporary conditions that require increased driver attention such as construction zones, hazardous roadways, or accident areas.

Uses For Portable Changeable Message Signs

Portable changeable message signs can be used in a variety of traffic situations to alert motorists of changes in the roadway. Some of these examples include:

  • Event congestion or traffic changes
  • Construction zones or roadway maintenance.
  • Upcoming changes in traffic or speed such as a lane closure or reopening.
  • Accidents or stalled vehicles in the roadway.
  • Traffic detours.
  • Speed reduction notification.
  • Adverse weather conditions such as flooding on the road.
  • Toll booths and weigh stations.


Alerting motorists to changes in their route improves the safety and flow of traffic. This results in fewer crashes as well as providing a safer environment for work zone crews.

Different Sizes to Meet Your Project Needs

We offer several sizes of changeable message signs, along with several options for each size. In addition, our message boards come with multiple programming options. Messages can be programmed from your phone or computer or by an onboard, easy-to-read touchscreen controller. Variable message signs are user-friendly and time-saving by allowing you to create a personalized library of messages. In addition, our message boards can be used in Queue Warning Systems and additional Smart Work Zone Applications, and push data can be sent to WAZEDOT 511 SystemsWork Zone Data Exchange, and more. No matter the size of your project, we offer a PCMS to meet your needs such as:

Full-Size Message Board (3-Line or Full-Matrix)

  • Displays three rows with eight 18” characters
  • High visibility
  • Ideal for highway and freeway applications

Mid-Size Message Board (Full-Matrix)

  • Perfect blend of the full size (high visibility) and the small size (highly maneuverable and easy to deploy)
  • Several character sizes and variations
  • Ideal for highway construction projects where space is limited and in urban areas

Small-Size Message Board (Full-Matrix)

  • Small trailer footprint for easy use in tight applications
  • Several character sizes and variations
  • Ideal for lower-speed roadways and narrow-shoulder applications

Since 1999, Street Smart has been helping traffic move safely throughout North America. We have the largest rental fleet of changeable message signs. Any quantity, any duration, anywhere, they are ready to get to work for you.

Portable Message Boards | Changeable Message Sign | Message Board (Product Overview)