ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · AUGUST 2021
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/august-2021-report
Monthly Traffic Safety Analysis
9,989 CRASHES IN
CHICAGO, IL
AUGUST 2021
Total crashes in Chicago increased from 9,161 in August 2020 to 9,989 in August 2021, representing a 9.04% rise. The most significant year-over-year shift was a 100% increase in total fatalities, rising from 11 to 22.
9,989
▲ 9.0%was 9,161
Total Crash Events
22
▲ 100.0%was 11
Persons Killed
2,066
▼ -1.8%was 2,104
Persons Injured
3,414
▲ 7.8%was 3,166
Hit-and-Run Crashes
Note: "Persons Killed" (22) counts individual fatalities across all crash events. "Fatal" in the severity table below (19) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 32 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall, crash activity in August 2021 showed an upward trend compared to August 2020. Total crashes increased by 828, a 9.04% rise, and total fatalities doubled from 11 to 22.
3,414
Hit-and-Run Crashes — August 2021
▲ 7.8% vs prior (3,166)
Hit-and-run crashes increased by 248, from 3,166 in August 2020 to 3,414 in August 2021, representing a 7.83% rise. The hit-and-run crash rate slightly decreased from 34.6% to 34.2% year-over-year.
Vulnerable Road User Casualties
4
Pedestrians Killed
1
Cyclists Killed
17
Motorists Killed
0
Other Killed
211
Pedestrians Injured
164
Cyclists Injured
1,689
Motorists Injured
2
Other Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · 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 Saturday in August 2020 (1,635 crashes) to Sunday in August 2021 (1,587 crashes). The peak hour also shifted, with 5 p.m. being the peak in August 2020 (693 crashes) and 4 p.m. in August 2021 (805 crashes).
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
Total fatalities increased by 100%, from 11 in August 2020 to 22 in August 2021, with fatal crashes rising from 11 to 19. The fatal crash rate increased from 0.12% to 0.19% year-over-year, while total injuries decreased slightly by 1.81%, from 2,104 to 2,066. The proportion of serious injuries remained relatively stable (2.1% to 2.0%), while minor injuries decreased from 10.3% to 9.6% and possible injuries from 4.3% to 3.8%.
Severity is per crash event (most severe injury). 19 fatal crash events resulted in 22 persons killed.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Most severe injury per crash record
Top Contributing Factors
Among contributing factors, 'IMPROPER OVERTAKING/PASSING' saw the largest percentage increase, rising by 123 crashes (34.26%) from 359 to 482. 'FAILING TO YIELD RIGHT-OF-WAY' also increased, with 97 more crashes, a 10.58% rise from 917 to 1014. Conversely, 'IMPROPER BACKING' decreased by 23 crashes (6.20%) from 371 to 348.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
Crashes occurring in 'CLEAR' weather conditions increased by 505 incidents, from 8,337 to 8,842. Crashes during 'DAYLIGHT' increased by 579, from 6,216 to 6,795, and those on 'DRY' road surfaces increased by 419, from 8,070 to 8,489. There was an increase of 51 crashes in 'RAIN' conditions and 93 crashes on 'WET' road surfaces year-over-year.
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Road surface condition field
Vehicles & Demographics
The total number of vehicles involved in crashes increased by 1,665 (8.85%), from 18,808 to 20,473. Among vehicle makes, TOYOTA saw a notable increase of 324 vehicles involved in crashes, from 1,707 to 2,031. The total number of persons involved in crashes increased by 1,762 (8.91%), from 19,765 to 21,527, with a significant increase of 320 persons in the 26-34 age group.
Top Vehicle Makes (20,473 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Vehicle unit records
6,922 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 (21,125 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · Person-level records linked to crash events
Speed Limit Zones
Crashes occurring in 30 mph speed zones increased by 659, from 6,716 to 7,375, and fatal crashes in these zones increased from 7 to 17. The fatal crash rate in 30 mph zones rose from 0.104% to 0.231%. Crashes in 45 mph zones increased from 45 to 61, but fatal crashes in these zones decreased from 3 to 0.
Fatal crashes by zone: 15 mph: 1 of 381 (0.262%) · 30 mph: 17 of 7,375 (0.231%) · 35 mph: 1 of 663 (0.151%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-08-01 to 2021-08-31 · 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: 2021-08-01 through 2021-08-31
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2021-08-01 through 2021-08-31 (31 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 9,989
- Total persons involved: 21,527
- Total vehicles involved: 20,473
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/august-2021-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: 2021-08-01 – 2021-08-31
Generated: June 1, 2026 · All rights reserved