The NTCIP standard is known as a protocol standard, but also specifies functionality required for field devices. Were it only a protocol standard, it would be possible to test for conformance using only a protocol analyzer. However, the standards that include test procedures always include functional testing also, such as verifying that messages are displayed correctly, cameras move appropriately, or intersection controllers cycle properly. To reflect this requirement that standards should specify functionality, many of the NTCIP standards have now been updated to conform to the Systems Engineering Process, where User Needs are listed, Functional Requirements are defined, and all elements of the final standards are traced back to these two groups of parameters.
Once the standard has been created, a remaining task of the standard is to clearly define mandatory and optional requirements, along with providing a means of communicating between the interested parties what optional requirements are needed by the specifying authority, or implemented by the manufacturer. The section of the standard that is used for this purpose is known as the Protocol Requirements List (PRL). In the standard, the PRL indicates whether a particular Functional Requirement is Mandatory. All Mandatory Functional Requirements must be implemented for a device to be considered conformant to the standard.
Alternately, a Functional Requirement may be listed as Optional, in which case a Specifying Authority can require that this Functional Requirement be supported by selecting “YES” under “Support/Project Requirement” in the PRL table. A field device provider would then be compliant with the Specifying Authority’s Specifications if this Functional Requirement is implemented. Note that the NTCIP standards allow Optional requirements to be conditional on whether other Optional requirements have been selected, ensuring that the selected requirements “hang together” to form a working system.
In addition to being able to select optional conformance requirements, the Specifying Authority can also indicate Additional Project Requirements. For some Functional Requirements guidance has been provided by the standard in the form of fill-in-the-blank statements. In this column the Specifying Authority may also reference separate documents, such as font tables or message lists for Dynamic Message Signs.
Not only can the PRL be used by a Specifying Authority for the purpose of defining their specific needs, but the PRL can also be completed by the manufacturer of the field device to indicate the Functional Requirements supported by their device. The PRL as completed by the manufacturer would then be known as a Protocol Implementation Conformance Statement (PICS). The PICS can then be used for several purposes. It can be used by the Specifying Authority to verify conformance to the standard and compliance with the specification. It can also be used by a third-party test organization to develop the Test Cases necessary to verify conformance and compliance by means of the Test Procedures.
Delcan Technologies, a Parsons Company, employs a full team of NTCIP experts who can guide any entity through the steps to ensure all aspects of implementing an Advanced Traffic Management System is in full compliance will industry standards.