The CTA’s Bus Tracker and Train Tracker systems rely on GPS data to provide real-time location and arrival estimates for buses and trains.
How often does CTA refresh GPS tracking data?
The refresh rate for this GPS tracking data is as follows
- Bus Tracker: Bus Tracker data is updated approximately every 30 seconds on the CTA website and in the API.
- Train Tracker: The database for Train Tracker is updated two or three times per minute, and in most web browsers, arrival information automatically refreshes about every 30 seconds.
It’s important to remember that
- While the data is refreshed frequently, the arrival times are still estimates based on scheduled travel times and vehicle locations, and extraneous circumstances like traffic can impact their accuracy.
- If a bus goes off-route or experiences a hardware or communication problem, it may temporarily disappear from the Bus Tracker system.
- For longer-term predictions (beyond about 30 minutes), it’s recommended to consult the scheduled service data available through the GTFS feed.