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 5401 Application Programming Interface (API) for the Advanced Transportation Controller (ATC) Standard is one of three ATC standards efforts. It defines a software platform that operates on an ATC controller unit (as defined by the ATC 5201 Advanced Transportation Controller Standard. The API Software that is developed according to the standard provides management capabilities and functional interfaces for the ATC unit's Front Panel, Field Input/Output Devices, and Real-time Clock. When combined with the ATC units's Linux operating system, the API Software provides a universal interface for application programs to operate on any ATC unit regardless of the manufacturer. In addition, it allows multiple application programs to operate concurrently on a single ATC unit by sharing the controller's computational resources, its Front Panel, its Real-time Clock, and access to the Field I/O devices of the cabinet system.

The ATC 5401 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.

Other standards within the ATC program include the ATC 5201 Advanced Transporation Controller Standard,  and the ATC 5301 ATC Cabinet Standard

Comments from potential users of the standard are solicited and request comments be submitted by October 30, 2022 at

 How to Submit Comments

Comments on the standard are welcomed at any time and are collected using the comment form and email it to However, when the

project/working group is active, then actions will be taken on comments received.

Version History Table

Version No.

Standard/Document Name

Overall Status Under Development / Published / Superseded Version

Date Completed

ATC 5401  API V02B.45

ATC 5401 v02B.45-Recommended Standard



Standard Development Report V02.45

SDR for v02B.45



ATC 5401  API User Comment Draft (UCD)

UCD ATC 5401 v02B.42



Standard Development Report V02B.42

SDR for v02B.42



ATC 5401  API V02A.35

ATC 5401 v02A.35-Recommended Standard



Standard Development Report V02A

SDR for v02A