Chicago Arterial Traffic Congestion Estimates by Segment 2018-2023

Over 1,000 traffic segments on Chicago's arterial streets have historical congestion estimates from February 2018 to September 2023. The data is generated by analyzing GPS traces from CTA buses to produce segment speed and regional congestion estimates every 10 minutes. This resource covers approximately 300 miles of principal arterials, offering a detailed view of non-freeway traffic patterns.

Use Cases

• Analyze segment speed volatility over time to identify arterial streets with the most frequent congestion fluctuations.
• Compare traffic region congestion estimates against individual segment speed data to understand localized versus area-wide traffic conditions.
• Model the impact of factors like intersections and traffic signals on segment speed using the historical time-series data.
• Correlate congestion estimates from over 1,000 segments with external events like crashes or transit movements mentioned in the description.

Strengths

• Covers over 1,000 individual traffic segments, providing granular spatial detail.
• Includes data from a 5.5-year time range (February 2018 to September 2023).
• Based on continuous real-time monitoring of GPS traces from a large fleet of CTA buses.
• Covers approximately 300 miles of Chicago's principal arterial streets.

Limitations

• Excludes freeway traffic and the O'Hare airport area, limiting comprehensive city-wide analysis.
• Segment speed data is described as having high volatility, which may complicate trend analysis.
• The dataset is split across multiple source links, requiring users to combine files for a complete historical view.

Provenance

Source

City of Chicago

Collection Method

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

Time Range

Approximately February 28, 2018 to September 8, 2023

Freshness

Historical data ends September 2023; metadata was last updated in May 2025.

Geography

Chicago, Illinois, USA (arterial streets only)