Chicago Arterial Traffic Congestion Estimates by Segment Since 2024

Over 1,000 traffic segments on Chicago's arterial streets are monitored for congestion, with estimates produced every 10 minutes starting June 11, 2024. The dataset is generated by analyzing GPS traces from Chicago Transit Authority buses to provide historical speed and congestion data. It covers approximately 300 miles of principal arterials, offering segment-level and region-level traffic condition insights.

Use Cases

• Analyze historical congestion patterns for over 1,000 traffic segments to identify recurring bottlenecks.
• Model the relationship between segment-level speed volatility and broader traffic region congestion estimates.
• Correlate traffic conditions on arterial streets with external events using the 10-minute interval time series data.
• Compare traffic patterns across the 29 defined traffic regions to understand city-wide flow dynamics.

Strengths

• Covers over 1,000 distinct traffic segments on Chicago's arterial network.
• Data is updated every 10 minutes, providing high temporal granularity.
• Monitors approximately 300 miles of principal arterial streets.
• Aggregates data into 29 traffic regions for more stable congestion analysis.

Limitations

• Limited to arterial streets, excluding freeway traffic data which is a major component of city traffic.
• Segment speed data is noted to have high volatility, which may complicate trend analysis.
• Historical depth is limited as the series begins in mid-2024, with older data in a separate, unlinked dataset.

Provenance

Source

City of Chicago

Collection Method

Generated by continuously monitoring and analyzing GPS traces from Chicago Transit Authority (CTA) buses.

Time Range

From June 11, 2024, onward (with one earlier record from March 8, 2024).

Freshness

Updated every 10 minutes; last metadata update was March 22, 2026.

Geography

Chicago, Illinois, USA, focusing on arterial (non-freeway) streets.