Portable changeable message signs (PCMS) and Flashing Arrow Panels (FAP) are traffic control devices that are frequently used by Traffic Engineers to inform motorists of unusual driving conditions, and to guide traffic through work zones. Typically, a PCMS is housed on a trailer or on a truck bed and can be deployed quickly for meeting the temporary requirements.
Use of PCMS and FAP are generally defined in the
MUTCD(1) : "Portable changeable message signs (PCMS) are traffic control devices with the flexibility to display a variety of messages to fit the needs of road and street authorities. Each message consists of one or more displays. PCMS are used most frequently on high density, urban freeways, but have applications on all types of highways where highway alignment, traffic routing problems or other pertinent conditions require advance warning and information."
The MUTCD further defines the use of Flashing Arrow Panels (sometimes referred to as "arrow display") as: "a sign with a matrix of elements. The matrix, capable of either flashing or sequential displays, is intended to provide additional warning and directional information to assist in merging and controlling traffic through or around a temporary traffic control zone. An arrow display should be used in combination with appropriate signs, barricades, or other traffic control devices.
The NTPEP Technical Committee responsible for authoring the Project Work Plan convenes yearly at the NTPEP National (Annual) Meeting. During this working meeting, the Project Work Plan is discussed; changes made, and shortly thereafter balloted for adoption. Improvements are immediately implemented in the next available testing cycle. When compared to other standards development exercises, the NTPEP process is agile, effective and efficient.