Chicago Arterial Traffic Congestion Estimates by Region, 2018-Present

Historical congestion estimates for Chicago's 29 traffic regions, starting in approximately March 2018. The data is generated by the Chicago Traffic Tracker, which monitors GPS traces from CTA buses to estimate speeds on non-freeway arterial streets every 10 minutes. This regional-level aggregation provides a more stable view of traffic conditions compared to volatile individual street segments.

Use Cases

• Analyzing daily or weekly congestion patterns using HOUR and DAY_OF_WEEK columns.
• Comparing traffic speeds across different city regions using REGION, REGION_ID, and SPEED.
• Correlating traffic conditions with geographic boundaries using Community Areas, Wards, and Zip Codes.
• Investigating the density of data samples for a region using BUS_COUNT and NUM_READS.
• Examining seasonal traffic trends by aggregating data by MONTH and TIME.

Strengths

• Covers a significant time range, with historical data from approximately March 2018 to the present.
• Data is derived from a real-time operational system (Chicago Traffic Tracker) using GPS traces from CTA buses.
• Aggregated to 29 traffic regions, which provides more consistent signals than volatile individual street segments.
• Available on multiple public platforms (Socrata, Data.gov), indicating official dissemination and reliability.

Limitations

• Key metadata such as row count, dataset size, license, and author are not provided by any source.
• The dataset excludes the O'Hare airport area from its geographic coverage of Chicago.
• The 'last updated' dates provided (2026-04-03, 2026-04-05) are in the future, indicating potential metadata errors.

Provenance

Source

Chicago Traffic Tracker, City of Chicago, via data.cityofchicago.org.

Collection Method

Real-time monitoring and analysis of GPS traces received from Chicago Transit Authority (CTA) buses.

Time Range

Approximately March 2018 to present.

Freshness

Last updated dates are reported as 2026-04 03 and 2026-04-05, which are implausible future dates.

Geography

City of Chicago, divided into 29 traffic regions (excluding O'Hare airport area).