About GTSS

Learn about the General Traffic Signal Specification and its mission to standardize traffic signal data with simple, open text files.

The General Traffic Signal Specification (GTSS) provides a simple, open, and universal framework for traffic signal data, configuration and location. By defining a minimal set of CSV files, GTSS makes it easy for cities, vendors, and developers to share, analyze, and develop signal systems reliably and consistently.

Mission

To create an open, practical standard for traffic signal systems that prioritizes safety, efficiency, interoperability, and innovation, while supporting the evolution toward smart, digitization of urban infrastructure.

Core Concept: Simple Files, Endless Possibilities

GTSS is intentionally simple. With a small set of plain text files, agencies can describe every intersection in a standardized way. The four original core files are:

  • agency.txt — Basic agency information: name, contact, and operational metadata.
  • signals.txt — Intersection locations, street names, and signal ID.
  • phases.txt — Each signal’s phasing, movement details and posted speed.
  • detectors.txt — Detection channels, types, and setback distance and lane assignments.


Together with approaches.txt and basic_timings.txt (added in v1.1), these files let agencies power performance monitoring, mapping, visualization, and analytics, while enabling developers to build new tools and services without extra configuration or proprietary barriers.

History

GTSS was created to solve a fragmented traffic signal landscape, where incompatible systems and proprietary protocols caused inefficiencies and vendor bias.

Get Involved

GTSS is an open specification, built with input from traffic engineers, city planners, technology companies, and safety advocates. Contributions are welcome from anyone interested in improving urban transportation systems.

Github: github.com/GTSS/
Discussions: github.com/GTSS/discussions