What is the maximum number of lines of text allowed in each phase of a DMS?

The maximum number of lines of text allowed in each phase of a Dynamic Message Sign (DMS) is three. This design standard is primarily aimed at ensuring clarity and readability for drivers, allowing for essential information to be displayed effectively without overwhelming them. Clear communication is critical for emergency vehicle operations, as it guarantees that messages can be understood quickly and accurately while drivers are in motion. When using three lines, operators can convey important updates, instructions, and alerts in a concise manner that can be swiftly processed by passing drivers, thereby enhancing safety on the road. Displaying too much information or utilizing too many lines can lead to confusion, increasing the risk of drivers overlooking vital messages, which is why the three-line standard has been established as optimal for DMS use.