ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · SEPTEMBER 2024
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-2024-report
Monthly Traffic Safety Analysis
9,816 CRASHES IN
CHICAGO, IL
SEPTEMBER 2024
In September 2024, Chicago recorded 9816 total crashes, an increase of 2.08% compared to the 9616 crashes in September 2023. A notable year-over-year shift was observed in total fatalities, which decreased by 15.38% from 13 in the prior year to 11 in the current period.
9,816
▲ 2.1%was 9,616
Total Crash Events
11
▼ -15.4%was 13
Persons Killed
2,396
▲ 8.2%was 2,214
Persons Injured
3,056
▲ 2.2%was 2,990
Hit-and-Run Crashes
Note: "Persons Killed" (11) counts individual fatalities across all crash events. "Fatal" in the severity table below (11) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 26 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall crash activity in Chicago increased slightly, with total crashes rising by 2.08% from 9616 in September 2023 to 9816 in September 2024. Despite this increase in crash volume, total fatalities decreased by 15.38%, falling from 13 to 11 year-over-year. However, total injuries saw an 8.22% increase, from 2214 to 2396.
3,056
Hit-and-Run Crashes — September 2024
▲ 2.2% vs prior (2,990)
The number of hit-and-run crashes increased by 2.21% year-over-year, rising from 2990 incidents in September 2023 to 3056 in September 2024. Despite this increase in count, the overall hit-and-run crash rate remained stable at 31.1% of all crashes for both periods.
Vulnerable Road User Casualties
1
Pedestrians Killed
1
Cyclists Killed
9
Motorists Killed
0
Other Killed
267
Pedestrians Injured
224
Cyclists Injured
1,889
Motorists Injured
16
Other Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)
When Crashes Happen
The peak day for crashes shifted from Friday in September 2023 (1815 crashes) to Sunday in September 2024 (1551 crashes), representing a 22.70% decrease on Fridays and a 38.11% increase on Sundays. The peak hour for crashes remained consistently at 3 PM for both periods, with 814 crashes in the current period compared to 792 in the prior period.
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The fatal crash rate decreased from 0.14% in September 2023 to 0.11% in September 2024, corresponding to a reduction from 13 fatal crashes to 11. While serious injury crashes (A) decreased slightly from 174 to 168, minor injury (B) and possible injury (C) crashes increased from 901 to 954 and 436 to 585, respectively. Overall, crashes resulting in any injury (A, B, or C) increased by 12.97% year-over-year, from 1511 to 1707.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Most severe injury per crash record
Top Contributing Factors
The top four contributing factors maintained their ranking year-over-year, all showing an increase in crash counts. 'FAILING TO YIELD RIGHT-OF-WAY' remained the leading factor, increasing by 127 crashes (11.96%) from 1062 to 1189. 'IMPROPER OVERTAKING/PASSING' saw a 20.39% increase in count, rising from 461 to 555 crashes. 'IMPROPER TURNING/NO SIGNAL' entered the top five in September 2024 with 333 crashes, while 'DRIVING SKILLS/KNOWLEDGE/EXPERIENCE' decreased by 12.74% from 369 to 322 crashes.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
A significant shift was observed in crash conditions, with crashes in clear weather increasing by 11.33% (from 7554 to 8410) and on dry road surfaces increasing by 11.19% (from 7161 to 7962). Conversely, crashes occurring in rain decreased by 45.61% (from 1037 to 564), and those on wet road surfaces decreased by 47.41% (from 1234 to 649). Crashes during daylight hours increased by 4.59% (from 6345 to 6636), while those in darkness on lighted roads decreased by 2.85% (from 1858 to 1805).
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Road surface condition field
Vehicles & Demographics
The total number of vehicles involved in crashes increased slightly by 0.65%, from 19877 in September 2023 to 20006 in September 2024. The top five vehicle makes involved in crashes remained consistent, with Toyota, Chevrolet, and Ford continuing to be the most frequently listed. All age groups for persons involved in crashes showed an increase year-over-year, with the 0-15 age group seeing the largest percentage increase of 7.02% (from 726 to 777 persons).
Top Vehicle Makes (20,006 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Vehicle unit records
6,332 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 (21,403 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · Person-level records linked to crash events
Speed Limit Zones
The 30 mph speed zone continued to account for the highest number of crashes, increasing by 1.73% from 7167 to 7291 crashes, and its fatal crash rate rose from 0.098% to 0.110%. Crashes in the 25 mph zone increased by 12.81% (from 609 to 687), and this zone recorded one fatal crash in the current period, compared to none previously. Conversely, while crashes in the 20 mph zone increased by 10.02% (from 409 to 450), fatal crashes in this zone decreased from two to zero.
Fatal crashes by zone: 25 mph: 1 of 687 (0.146%) · 30 mph: 8 of 7,291 (0.11%) · 35 mph: 2 of 598 (0.334%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2024-09-01 to 2024-09-30 · 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: 2024-09-01 through 2024-09-30
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2024-09-01 through 2024-09-30 (30 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 9,816
- Total persons involved: 21,803
- Total vehicles involved: 20,006
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-2024-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: 2024-09-01 – 2024-09-30
Generated: June 1, 2026 · All rights reserved