Application Programming Interface (API) Standard for the Advanced Transportation Controller (ATC)

The Advanced Transportation Controller (ATC) Standards are intended to provide an open architecture hardware and software platform that can support a wide variety of Intelligent Transportation Systems (ITS) applications including traffic management, safety, security and other applications. The ATC Standards are being developed and maintained under the direction of the ATC Joint Committee (JC) which is made up of representatives from the American Association of State Highway and Transportation Officials (AASHTO), the Institute of Transportation Engineers (ITE), and the National Electrical Manufacturers Association (NEMA).

The ATC Application Programming Interface (API) Standard is one of four ATC standards efforts. It defines a software platform that operates on an ATC controller unit (as defined by the ATC Controller Standard). The API software provides management capabilities and functional interfaces for the ATC controller's Front Panel, the controller cabinet's Field Input/Output Devices, and the controller's Time. When combined with the ATC controller's operating system, the API software provides a universal interface for application programs to operate on any ATC controller unit regardless of the manufacturer. In addition, it allows multiple application programs to be interoperable on a single ATC controller unit by sharing the controller's fixed resources.

The ATC API Standard has been prepared by the ATC API Working Group (WG), a technical subcommittee of the ATC JC. It establishes a common understanding of the user needs, requirements, and specification of the interface for:

1. The local, state, and federal transportation agencies who specify ATC equipment;
2. The software developers, consultants, and manufacturers who develop application programs for ATC equipment; and
3. The public who benefits in the application programs that run on ATC equipment and directly or indirectly pays for these products.

• ATC Joint Committee and Interested Parties
• Voting Members of the ATC API Working Group

Other standards within the ATC program include the Model 2070 Standard, the ATC Controller Standard, and the Intelligent Transportation Systems (ITS) Cabinet Standard.

ATC 5401 v02A

The Application Programming Interface (API) Standard for the Advanced Transportation Controller (ATC) Version 2 (v02.17) was published as a Joint Standard of AASHTO, ITE and NEMA on September 1, 2011. On September 12, 2013, it was republished with the “ATC 5401” identifier in the name for administrative purposes and without modification to the technical content of the standard. Following this, the ATC JC requested funding to build a software reference implementation of the ATC 5401 Standard that could discover and correct any deficiencies in the standard and provide API software that manufacturers could use freely in their controller units. This approach would provide the best opportunity for portability, compatibility, and interchangeability of ATC application software. This decision was supported by all controller manufacturers involved in the ATC program. Funding from the USDOT was received and resulted in the API Reference Implementation (APIRI) project (see https://www.ite.org/technical-resources/standards/api-reference-implementation/).

ATC 5401 v02A.35 represents a significantly improved version of the standard and rectifies the deficiencies in the previous version. This version of the standard correlates to the current status of the APIRI project. Improvements included:

1. Editorial changes
2. Changes to three of the existing Configuration Utilities
3. Addition of three new Configuration Utilities
4. Improved descriptions to seven API functions
5. Corrections to eight API functions
6. Addition of three new API functions
7. Removed one function

The API WG submitted ATC 5401 Standard v02A.35 to the ATC JC for review as a Proposed Recommend Standard (pRS). The ATC JC accepted the document as a Recommended Standard during their teleconference on June 20, 2019 with a vote of 8 yeas, 0 nays, and 0 abstentions.

Version History Table