ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · SEPTEMBER 2023
Purpose: Machine-readable JSON endpoint for AI agents, LLMs, researchers, and programmatic consumers. Returns all underlying crash data and AI-generated commentary without HTML.
Authentication: None required. Public endpoint.
GET: https://thatcarhitme.com/api/crash-data/reports/data/illinois/chicago/september-2023-report
Monthly Traffic Safety Analysis
9,616 CRASHES IN
CHICAGO, IL
SEPTEMBER 2023
Total crashes increased slightly from 9602 in September 2022 to 9616 in September 2023, a 0.15% rise. Despite this, total fatalities saw a notable decrease of 13.33%, falling from 15 to 13 year-over-year. Meanwhile, total injuries increased by 9.66%, from 2019 to 2214.
9,616
▲ 0.1%was 9,602
Total Crash Events
13
▼ -13.3%was 15
Persons Killed
2,214
▲ 9.7%was 2,019
Persons Injured
2,990
▼ -4.5%was 3,132
Hit-and-Run Crashes
Note: "Persons Killed" (13) counts individual fatalities across all crash events. "Fatal" in the severity table below (13) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 31 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall crash volume remained relatively stable year-over-year, with a minor increase of 0.15% from 9602 to 9616 crashes. Fatalities decreased by 13.33%, from 15 to 13, while total injuries increased by 9.66%, rising from 2019 to 2214. This indicates a shift towards more injury-involved crashes but fewer fatal outcomes.
2,990
Hit-and-Run Crashes — September 2023
▼ -4.5% vs prior (3,132)
The number of hit-and-run crashes decreased by 142, falling from 3132 to 2990, a 4.53% reduction. Consequently, the hit-and-run rate also decreased by 1.5 percentage points, from 32.6% to 31.1% year-over-year. This indicates a downward trend in hit-and-run incidents.
Vulnerable Road User Casualties
3
Pedestrians Killed
0
Cyclists Killed
10
Motorists Killed
0
Other Killed
236
Pedestrians Injured
195
Cyclists Injured
1,775
Motorists Injured
8
Other Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)
When Crashes Happen
The peak day for crashes remained Friday in both periods, though the count decreased slightly from 1843 to 1815 crashes. Similarly, the peak hour stayed at 3 PM, with crash counts falling from 817 to 792. Notable shifts in daily patterns include a decrease of 496 crashes on Thursdays and an increase of 373 crashes on Saturdays.
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The number of fatal crash events remained constant at 13 in both periods, maintaining a fatal rate of 0.14%. However, the total number of persons killed decreased from 15 to 13, a 13.33% reduction. Conversely, total injuries increased by 9.66%, rising from 2019 to 2214 persons.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Most severe injury per crash record
Top Contributing Factors
The top two contributing factors, "FAILING TO YIELD RIGHT-OF-WAY" and "FOLLOWING TOO CLOSELY," both saw slight increases in count, rising by 15 (1.43%) and 9 (1.08%) crashes respectively. "IMPROPER LANE USAGE" experienced a notable decrease of 68 crashes, a 19.37% reduction. Additionally, "WEATHER" as a contributing factor significantly increased by 27 crashes, representing a 64.29% rise.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
Crashes occurring in clear weather conditions decreased by 777, while those in rainy conditions significantly increased by 571, more than doubling from 466 to 1037. This aligns with a substantial increase of 645 crashes on wet road surfaces, which more than doubled from 589 to 1234. Crashes in daylight and lighted dark conditions decreased, while those in unlit darkness, dusk, and dawn increased.
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Road surface condition field
Vehicles & Demographics
The total number of vehicles involved in crashes increased by 300, from 19577 to 19877. Among vehicle types, pedestrian-involved vehicles increased by 35 (13.83%), and bicycle-involved vehicles increased by 26 (10.92%). Toyota surpassed Chevrolet to become the most frequently involved vehicle make, with 2395 crashes compared to Chevrolet's 2013.
Top Vehicle Makes (19,877 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Vehicle unit records
6,566 persons with unknown or unrecorded age excluded from age chart. Age=0 in Chicago records is a sentinel for unknown/unrecorded age (not infants) and is grouped with nulls.
Sex Distribution (20,969 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Person-level records linked to crash events
Speed Limit Zones
Crashes in 30 MPH zones, which account for the majority, saw a slight increase of 116 crashes (1.64%), rising from 7051 to 7167, though fatalities in these zones decreased from 10 to 7. Conversely, 15 MPH zones, despite a slight decrease in total crashes, recorded 1 fatal crash in the current period compared to none prior. Similarly, 20 MPH zones saw 2 fatal crashes in the current period despite a decrease in total crashes from 460 to 409.
Fatal crashes by zone: 15 mph: 1 of 347 (0.288%) · 20 mph: 2 of 409 (0.489%) · 30 mph: 7 of 7,167 (0.098%) · 35 mph: 2 of 649 (0.308%) · 40 mph: 1 of 78 (1.282%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2023-09-01 to 2023-09-30 · Posted speed limit at crash location
Data Sources & Methodology
Primary Data Source
All crash data in this report is sourced from Chicago Traffic Crashes, accessed programmatically via the Socrata Open Data API (SODA). This dataset contains official police-reported motor vehicle traffic crash records maintained by the reporting jurisdiction's law enforcement agency. Records are published to the open data portal by the municipality and are subject to the portal's terms of use.
Data Retrieval
- Access method: Socrata Open Data API (SoQL queries)
- Data format: Structured JSON via REST API
- Record types queried: Crash events, person records, and vehicle unit records
- Date filter applied: 2023-09-01 through 2023-09-30
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2023-09-01 through 2023-09-30 (30 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 9,616
- Total persons involved: 21,472
- Total vehicles involved: 19,877
Analytical Methodology
- Severity classification: Uses the KABCO injury scale (K=Fatal, A=Incapacitating injury, B=Non-incapacitating injury, C=Possible injury, O=No injury/property damage only), the standard classification in U.S. Model Minimum Uniform Crash Criteria (MMUCC). Severity is assigned per crash event based on the most severe injury in that crash. A single fatal crash (K) may involve multiple fatalities; therefore the "Persons Killed" count in the headline KPIs may differ from the "Fatal" crash count in the severity breakdown.
- Contributing factors: Reflect the officer-determined primary contributory cause recorded at the time of the crash report. These are preliminary determinations and may not reflect final investigation findings.
- Hit-and-run classification: Based on the hit-and-run indicator field in the official crash report, as determined by the responding officer at the scene.
- Temporal analysis: Day-of-week and hour-of-day distributions are computed from the crash date/time timestamp in each record.
- Demographics: Age and sex distributions are drawn from person-level records linked to each crash event. A single crash may involve multiple persons.
- Vehicle data: Make information is drawn from vehicle unit records linked to each crash event.
- AI commentary: Narrative sections are generated by Google Gemini (large language model) based on the structured data. Commentary is descriptive, not predictive, and should not be interpreted as expert opinion.
Limitations & Disclaimers
- Only crashes reported to and documented by law enforcement are included. Minor incidents, unreported crashes, and near-misses are not captured in this dataset.
- Data reflects conditions at the time of the initial police report and may be subject to subsequent corrections, reclassifications, or supplements by the reporting agency.
- Open data portal records may experience a publication lag - recently occurring crashes may not yet appear in the dataset at the time of report generation.
- AI-generated commentary is produced by a large language model and is intended to highlight patterns in the data. It does not constitute legal, medical, or professional analysis.
- Percentages are calculated from reported data and are subject to rounding.
Non-Affiliation Disclosure
This report is produced independently by ThatCarHitMe.com (Injuria.ai). It is not affiliated with, endorsed by, or produced in partnership with any law enforcement agency, municipal government, state department of transportation, or the National Highway Traffic Safety Administration (NHTSA). Data is sourced from publicly available government open data portals.
Data License
The underlying crash data is provided under the municipality's Open Data Terms of Use and is made available to the public for unrestricted use. This analysis and report is © 2026 Injuria.ai and may be cited with attribution using the suggested citation below.
Corrections & Feedback
If you believe any data in this report is inaccurate or have questions about our methodology, please contact: data@injuria.ai. We are committed to accuracy and will issue corrections promptly.
Suggested Citation
ThatCarHitMe.com (Injuria.ai). "Chicago, IL Crash Intelligence Report." Published June 1, 2026. Data source: Chicago Traffic Crashes, Socrata Open Data. Available at: https://thatcarhitme.com/crash-data/illinois/chicago/september-2023-report
About the Publisher
ThatCarHitMe.com is a crash data intelligence platform developed by Injuria.ai, a legal technology company specializing in traffic safety analytics. We aggregate and analyze publicly available government crash data to produce structured intelligence reports for communities, researchers, journalists, and legal professionals. Our reports combine programmatic data retrieval from official open data portals with AI-assisted narrative analysis.
Questions about this report's data or methodology: data@injuria.ai
ThatCarHitMe.com · An Injuria.ai Company
ThatCarHitMe.com
An Injuria.ai Company
Crash Data Intelligence
Data: Chicago Traffic Crashes · Socrata
Period: 2023-09-01 – 2023-09-30
Generated: June 1, 2026 · All rights reserved