National Transportation Communications for Intelligent Transportation System Protocol
The National Transportation Communications for Intelligent Transportation System Protocol (NTCIP) is a family of standards designed to achieve interoperability and interchangeability between computers and electronic traffic control equipment from different manufacturers. NTCIP has been around for over 20 years, but is increasingly in use in smart city initiatives and by suppliers of technology. For example, riders who want to know where the next bus will arrive at their stop are using apps that use NTCIP, such as in the Siemens initiatives in Seattle and elsewhere. In the future, NTCIP will be used  for two way communication between vehicles and traffic signals, such as the ability for buses to control traffic lights as done by SinWaves. The protocol is the product of a joint standardization project guided by the Joint Committee on the NTCIP, which is composed of six representatives each from the National Electrical Manufacturers Association (NEMA), the American Association of State Highway and Transportation Officials (AASHTO), and the Institute of Transportation Engineers (ITE). The Joint Committee has in turn formed 14 technical working groups to develop and maintain the standards, and has initiated or produced over 50 standards and information reports . The project receives funding under a contract with the United States Department of Transportation (USDOT) and is part of a wider effort to develop a comprehensive family of intelligent transportation system (ITS) standards. History of the NTCIP Development. NEMA initiated the development of the NTCIP in 1992. In early 1993, the US Federal Highway Administration (FHWA) brought together transportation industry representatives to discuss obstacles to installing field equipment for new Intelligent Transportation Systems (ITS). The representatives said that the number one priority was the need for an industry-wide standard data communications protocol. Since the NEMA Transportation Section members had  already started work on a new industry standard, they offered to expedite and expand the scope of their activities. The key objectives of the new NTCIP protocol were the interchangeability of similar roadside devices, and the interoperability of different types of devices on the same communications channel. In 1996, the FHWA suggested a partnership of standards developing organizations to expand both user and industry involvement. AASHTO and ITE signed an agreement with NEMA to establish the Joint Committee on the NTCIP, and to work together on developing and maintaining the NTCIP standards. NTCIP Communications Standards. Center to Field Device Communications . NTCIP has enabled the center to field communication and command/control of equipment from different manufacturers to be specified, procured, deployed, and tested. NTCIP communications standards for field devices are listed below: (the corresponding NTCIP document number is shown in parentheses): Center to Center Communications. Center to center (C2C) communication involves peer-to-peer communications between computers involved in information exchange in real-time transportation management in a many-to-many network. This type of communication is similar to the Internet, in that any center can request information from, or provide information to, any number of other centers. An example  of center to center communications is two traffic management centers that exchange real-time information about the inventory and status of traffic control devices. This allows each center system to know what timing plan, for example, the other center system is running to allow traffic signal coordination across center geographic boundaries. Other examples of this type of communication include: NTCIP communications standards for center to center communications are listed below: (the corresponding NTCIP document number is shown in parentheses): The NTCIP has coordinated with other information level standards development organizations during development of the center-to-center application profiles and  supports the: ITE Traffic Management Data Dictionary (ITE TMDD), IEEE 1512 Incident Management (IEEE 1512), APTA Transit Communications Interface Profiles (APTA TCIP), and SAE J2354 Advanced Traveler Information Systems standards. NTCIP Standards Framework. The NTCIP Framework is based primarily on the open standards of the Internet Engineering Task Force (IETF), World Wide Web Consortium (W3C), and ISO, plus NTCIP data dictionary standards specific for the task of ITS device communications. A layered, or modular, approach to communications standards, is used to represent data communications between two computers or other electronic devices. NTCIP refers to “levels” in NTCIP, rather than “layers ” to distinguish the hierarchical architecture applied from those defined by the Open System Interconnection Reference Model (OSI Model) of ISO and the Internet Engineering Task Force (IETF). The five NTCIP levels are: information level, application level, transport level, subnetwork level, and plant level. The figure below (used with permission) shows the structure of the NTCIP Information, Application, Transport, Subnetwork, and Plant Levels. To ensure a working system, deployers should select and specify at least one NTCIP protocol or profile at each level. A discussion of each level, and NTCIP standards that apply at that level, follows: The NTCIP Framework does  not preclude combinations beyond those expressly indicated on the diagram.