Dynamic Message Signs (DMSs), also known as variable-message signs, are traffic control devices that provide real-time traveler information. These electronic signs can be used for the purposes of displaying traffic warning, regulation, routing, and management, and they are a major component of advanced traveler systems implemented by state departments of transportation (DOT). DMSs are commonly found on highways, but also make appearances on rural roads.
The messages conveyed to drivers through DMSs include emergencies, such as evacuations or closures, hazardous road conditions, such as severe weather conditions and work zone activities, traveler information and suggested alternative routes, travel times, ozone alerts, advance time notice for scheduled incidents, such as closures, and approved standard service announcements associated with special campaigns or other public information that reduces congestion.
The utilization of dynamic message signs, due to their visibility and basic comprehensibility, can yield some significant benefits. For example, during scheduled road work, DMSs have been shown to generate major increases in traffic flow, as they orderly guide drivers through established detours. This heightened traffic efficiency often results in a corresponding growth in time savings and operating cost savings.
NEMA TS 4-2016 – Hardware Standards for Dynamic Message Signs (DMS) with NTCIP Requirements standardizes the different units of dynamic message sign equipment. It is concerned with the electrical requirements, environmental requirements, mechanical construction, controller, and display properties of DMSs. The specifications detailed in this standard are useful for assuring the reliability of dynamic message signs during their daily use and after continuous interaction with anticipated forces, such as weather patterns.
NEMA TS 4-2016 is intended for use with dynamic message signs using NTCIP (National Transportation Communications for ITS Protocol) recommendations. The DMSs that utilize the NEMA standard for guidance also derive specifications from NTCIP 1203 v03 – Object Definitions for Dynamic Message Signs (DMS). This standard specifies the logical interface between dynamic message signs and the host systems that control them (the central systems). By addressing the architecture of DMS systems, NTCIP 1203 v03 can assure the delivery of timely and reliable information to the traveling public.
Adherence to the guidelines in NEMA TS 4-2016 and NTCIP 1203 v03 allows for dynamic message signs to be installed and used in a manner that captures their benefits for the public. For information on the federal requirements for DMSs, please refer to the Manual on Uniform Traffic Control Devices (MUTCD).
NEMA TS 4-2016 – Hardware Standards for Dynamic Message Signs (DMS) with NTCIP Requirements and NTCIP 1203 v03 – Object Definitions for Dynamic Message Signs (DMS) are available on the ANSI Webstore.
