GTFS-flex
A proposed extension to GTFS for modeling demand-responsive transportation services like on-demand and same-day transit.
What is GTFS-flex?
GTFS-Flex is a proposed extension to the General Transit Feed Specification (GTFS) that adds support for modeling demand-responsive transportation (DRT) services, such as on-demand and same-day transit. It solves the limitation of standard GTFS, which only covers fixed-route public transportation, by enabling trip planners to incorporate flexible transit options.
Transit agencies, mobility data providers, and developers working on trip planning applications who need to integrate flexible transit services into their systems.
It provides a standardized way to represent flexible transit services, ensuring compatibility with existing GTFS tools and enabling broader adoption of demand-responsive transit in trip planning software.
Overview
NOTICE: GTFS-Flex has been merged to GTFS. This repo is no longer up-to-date and will deprecated. Consult the google/transit repo for the up-to-date info.
Use Cases
Best For
- Extending GTFS feeds to include on-demand transit services
- Integrating flexible transit options into trip planning applications
- Standardizing data for demand-responsive transportation providers
- Enhancing public transportation data with non-fixed-route services
- Supporting trip planners like OpenTripPlanner with flexible transit routing
- Modeling same-day or dynamically scheduled transit services
Not Ideal For
- New projects needing the official, maintained GTFS-Flex specification, as this repository is deprecated and the spec has been merged into the main GTFS repo.
- Teams requiring active support or documentation updates, since this repo is no longer maintained and information may be outdated.
- Organizations looking for a finalized, stable spec without the complexities of a historical proposal, as this version is superseded.
Pros & Cons
Pros
Extends GTFS to formally model demand-responsive services like on-demand and same-day transit, enabling consistent data representation for trip planning.
Maintains compatibility with existing GTFS feeds, allowing seamless integration with current tools and systems without breaking functionality.
Already produced for over 100 transit services and consumed by OpenTripPlanner version 2, demonstrating real-world adoption and practicality.
Specifically designed to allow trip planners to discover and route through flexible transit options, expanding public transportation coverage.
Cons
The README states this repo is no longer up-to-date and will be deprecated, making it an unreliable source for current implementations or support.
As a proposed extension, it introduces additional files and data structures (e.g., new flex tables), increasing the complexity of GTFS feed creation and processing.
With the spec merged into the main GTFS repository, this version is outdated and not recommended for new projects, potentially causing confusion.
Frequently Asked Questions
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