How to Add Real-Time GTFS-RT to Your Transit Service

What Is GTFS Realtime?

GTFS Realtime (GTFS-RT) is an extension to the standard GTFS Schedule format that lets you share live data about your service. While your GTFS Schedule feed tells riders when your buses should arrive, GTFS-RT tells them when your buses will actually arrive — accounting for delays, traffic, and real-world conditions.

GTFS-RT is used by Google Maps, Apple Maps, and dozens of other trip planning apps to show:

  • Vehicle positions — Live dots on the map showing exactly where each vehicle is right now
  • Trip updates — Predicted arrival times at each stop, updated in real time
  • Service alerts — Notifications about delays, disruptions, detours, or stop closures

For riders, real-time data transforms the experience — instead of standing at a bus stop wondering if the bus is running late, they can see exactly where it is and plan accordingly.

GTFS-RT vs GTFS Schedule: What's the Difference?

Your GTFS Schedule feed is a static snapshot of your planned service — it describes the timetable as it would run under normal conditions. GTFS-RT is a live data stream that overlays actual, current conditions on top of that planned schedule. You need both: GTFS Schedule tells apps what your service looks like; GTFS-RT tells apps how it is actually performing right now.

Three GTFS-RT Feed Types
  • Vehicle Positions
    Live GPS location of each vehicle
  • Trip Updates
    Predicted arrival/departure times
  • Service Alerts
    Delays, detours, and disruptions

What You Need to Add GTFS-RT

GPS devices on your vehicles

To provide live vehicle positions, your vehicles need a GPS device that reports their location in real time. This can be a dedicated AVL (Automatic Vehicle Location) unit, a GPS tracker, or a driver smartphone app that shares location. The device needs to send location data to a server at a regular interval — typically every 5–30 seconds.

A system to generate GTFS-RT feeds

Raw GPS data from your vehicles needs to be converted into GTFS-RT format — a protocol buffer binary format specified by Google. This requires software that takes vehicle positions and matches them to your GTFS Schedule trips to produce the three GTFS-RT feed types. AddTransit handles this conversion for you.

A public endpoint for your GTFS-RT feeds

GTFS-RT feeds must be available at a public URL that apps like Google Maps can query in real time. Unlike GTFS Schedule (which is a static file updated occasionally), GTFS-RT feeds are queried every 15–30 seconds by consuming applications. Your hosting solution needs to serve fresh data on every request.

Step-by-Step: Setting Up GTFS-RT

Step 1 — Ensure you have a valid GTFS Schedule feed first

GTFS-RT is an extension of GTFS Schedule — it references the same trip IDs, route IDs, and stop IDs as your static feed. If you do not have a GTFS Schedule feed yet, start there. See our guide on how to create a GTFS feed from scratch. The trip IDs in your GTFS-RT feed must exactly match those in your GTFS Schedule.

Step 2 — Install GPS tracking on your vehicles

Choose a GPS tracking solution appropriate for your fleet. Options range from dedicated hardware units that plug into your vehicle's OBD port, to SIM-card-based trackers, to driver smartphone apps. The key requirement is that the device reports location at least every 30 seconds and sends data to a central server you can query.

Step 3 — Choose or build a GTFS-RT generator

This is the technically complex step. A GTFS-RT generator takes the live GPS data from your vehicles, matches each vehicle to a GTFS trip, and produces GTFS-RT protocol buffer feeds. Options include:

Step 4 — Host your GTFS-RT endpoints

Your three GTFS-RT feeds (vehicle positions, trip updates, and service alerts) each need a publicly accessible URL. AddTransit hosts these for you. If you are building your own system, ensure your server can handle frequent requests and serves fresh data on every hit — GTFS-RT feeds are typically fetched every 15–30 seconds by consuming applications.

Step 5 — Register your GTFS-RT feeds with Google

Submit your GTFS-RT feed URLs to Google via the Transit Partner Portal, linking them to your existing GTFS Schedule feed. Google will begin incorporating your real-time data into Maps arrival predictions. The same URLs can be shared with Apple Maps and other trip planning apps.

Step 6 — Test and verify

After submitting, check that vehicle positions appear on Google Maps when your vehicles are running. Verify that arrival time predictions update as vehicles move. Test service alerts by creating a test alert and confirming it appears correctly in the consuming application. Monitor your feeds regularly to catch any gaps in GPS coverage or data quality issues.

How AddTransit Makes GTFS-RT Simple

Setting up GTFS-RT from scratch requires software development skills, server infrastructure, and ongoing maintenance. AddTransit provides a turnkey GTFS-RT solution: connect your GPS devices to AddTransit, and the platform generates and hosts all three GTFS-RT feed types for you. Because AddTransit also manages your GTFS Schedule feed, the trip IDs are always in sync — a common source of errors when using separate systems.

Set up real-time tracking with AddTransit

Frequently Asked Questions

GTFS Schedule alone is enough to appear in Google Maps with planned departure times. GTFS-RT adds live vehicle positions and real-time arrival predictions. Both are valuable, but GTFS Schedule is the essential foundation. Start with GTFS Schedule, then add GTFS-RT when you have GPS tracking available.

GTFS-RT uses Google Protocol Buffers (protobuf), a compact binary format. Unlike GTFS Schedule which uses plain text CSV files, GTFS-RT feeds are binary and must be generated by software. This is why a tool or platform to generate GTFS-RT feeds is required — you cannot create them manually in a spreadsheet.

GTFS-RT feeds should be updated at least every 30 seconds. Google Maps and other apps query GTFS-RT feeds frequently to show up-to-date positions and predictions. GPS devices should report vehicle location at a similar interval — every 10–30 seconds is typical.

Yes. The cost of GPS hardware has fallen significantly. Basic vehicle trackers cost $20–$50 USD, and platforms like AddTransit provide the GTFS-RT generation and hosting at an affordable subscription price. The biggest barrier for small agencies is usually the technical setup, which AddTransit eliminates by handling everything through a simple dashboard.
Related How-To Guides