Terms and data sources
What this is
Chicago Data Maps shows how Chicago's streets are moving, measured from the positions of CTA buses. It is a picture of the city's movement, not a tool for catching a bus. For arrival times use the CTA's own Bus Tracker and Train Tracker services or any transit app.
Where the data comes from
- Vehicle positions come from the Chicago Transit Authority's Bus Tracker developer feed under the CTA Developer License Agreement and Terms of Use. We poll the feed once a minute from our own servers. The CTA is not involved in operating this site and does not see who visits it.
- Speeds, street pace, bunching, the hour-of-week patterns and every other number on this page are our own estimates, computed from those positions. They are not CTA statistics and the CTA has not reviewed them.
- Map: OpenStreetMap data, © OpenStreetMap contributors, available under the Open Database License (opendatacommons.org/licenses/odbl/1-0/), rendered from a Protomaps basemap that we host ourselves.
- Community area boundaries and the city's nine sides are drawn from the City of Chicago data portal (dataset "Boundaries - Community Areas").
Required notice — City of Chicago data
This site provides applications using data that has been modified for use from its original source, www.cityofchicago.org, the official website of the City of Chicago. The City of Chicago makes no claims as to the content, accuracy, timeliness, or completeness of any of the data provided at this site. The data provided at this site is subject to change at any time. It is understood that the data provided at this site is being used at one's own risk.
No affiliation
Chicago Data Maps is made by Common Signal LLC. It is not made, endorsed, sponsored or reviewed by the Chicago Transit Authority, and it is not a CTA service. "CTA", "Bus Tracker" and "Train Tracker" are marks of the Chicago Transit Authority, used here only to identify the source of the data.
No warranty
Everything on this site is provided as is, with no warranty of accuracy, completeness or availability. The underlying feeds can be delayed, incomplete or withdrawn at any time; buses that go off route or lose contact with the CTA's systems do not appear in the feed and so do not appear here. Do not rely on this site for any decision where being wrong would cost you something. To the fullest extent permitted by law, Common Signal LLC is not liable for any loss arising from use of this site.
Use of this site
You may read, link to and share this site freely. The numbers and pictures on it are ours; the vehicle positions behind them belong to the CTA and are licensed to us, not to you. We do not offer bulk downloads or an API at this time. If you would like to use our data in your own work, write to zach@commonsignaldata.com.
Changes
We may change or take down any part of this site at any time. This page is dated at the bottom; the date changes when the text does.
This page: 2026-10-12.