ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · MARCH 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/march-2021-report
Monthly Traffic Safety Analysis
7,679 CRASHES IN
CHICAGO, IL
MARCH 2021
In March 2021, Chicago experienced 7679 total crashes, a 15.1% increase compared to 6672 crashes in March 2020. The most significant year-over-year shift was in total fatalities, which rose by 233.3% from 3 to 10. This indicates a notable increase in both crash frequency and severity.
7,679
▲ 15.1%was 6,672
Total Crash Events
10
▲ 233.3%was 3
Persons Killed
1,451
▼ -1.4%was 1,472
Persons Injured
2,708
▲ 37.0%was 1,976
Hit-and-Run Crashes
Note: "Persons Killed" (10) counts individual fatalities across all crash events. "Fatal" in the severity table below (9) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 18 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall, crash incidents in Chicago increased year-over-year, with total crashes rising by 15.1% from 6672 in March 2020 to 7679 in March 2021. This indicates an upward trend in crash frequency for the specified period.
2,708
Hit-and-Run Crashes — March 2021
▲ 37.0% vs prior (1,976)
Hit-and-run crashes increased significantly year-over-year, rising by 37.0% in count from 1976 to 2708. The hit-and-run rate also trended upwards, increasing by 5.7 percentage points from 29.6% in March 2020 to 35.3% in March 2021.
Vulnerable Road User Casualties
3
Pedestrians Killed
0
Cyclists Killed
7
Motorists Killed
164
Pedestrians Injured
47
Cyclists Injured
1,240
Motorists Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)
When Crashes Happen
The peak day for crashes remained Monday in both March 2020 (1183 crashes) and March 2021 (1250 crashes). However, the peak crash hour shifted from 4 PM with 562 crashes in the prior period to 3 PM with 627 crashes in the current period.
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The fatal crash rate significantly increased from 0.04% in March 2020 to 0.12% in March 2021, corresponding to a rise in total fatalities from 3 to 10. While serious injury crashes saw a slight decrease in proportion from 2% to 1.8%, minor injury crashes increased from 7.9% to 8.3%. Possible injury crashes decreased from 4.9% to 3.6% of total crashes.
Severity is per crash event (most severe injury). 9 fatal crash events resulted in 10 persons killed.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Most severe injury per crash record
Top Contributing Factors
"FAILING TO YIELD RIGHT-OF-WAY" remained the leading contributing factor, increasing from 741 crashes in March 2020 to 801 crashes in March 2021, an 8.1% rise in count. "FOLLOWING TOO CLOSELY" also increased by 1.5% in count, from 588 to 597 crashes. Notably, "IMPROPER OVERTAKING/PASSING" crashes increased by 37.7% in count, from 268 to 369, moving into the top three factors while "FAILING TO REDUCE SPEED TO AVOID CRASH" decreased by 5.3% in count from 356 to 337.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
The proportion of crashes occurring in clear weather conditions increased, with clear weather crashes rising by 27.0% in count from 5219 to 6630. Conversely, crashes during rain decreased by 49.2% in count, from 721 to 366. There was a notable increase in crashes on snow or slush road surfaces, rising by 251.5% in count from 33 to 116.
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Road surface condition field
Vehicles & Demographics
The total number of vehicles involved in crashes increased by 14.3%, from 13768 in March 2020 to 15736 in March 2021. The age group 26-34 saw a 4.7% increase in persons involved in crashes, and the 35-44 age group increased by 8.4%. Chevrolet and Ford remained the top two vehicle makes involved, with Toyota replacing Nissan as the third most common make.
Top Vehicle Makes (15,736 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Vehicle unit records
5,013 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 (16,009 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · Person-level records linked to crash events
Speed Limit Zones
Crashes in 30 mph speed zones increased by 16.0% in count, from 4797 to 5565, and the fatal rate in these zones rose from 0.042% to 0.162%. Crashes in 35 mph speed zones also increased by 17.8% in count, from 454 to 535, though the fatal rate in this zone decreased from 0.22% to 0%.
Fatal crashes by zone: 30 mph: 9 of 5,565 (0.162%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2021-03-01 to 2021-03-31 · 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: 2021-03-01 through 2021-03-31
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2021-03-01 through 2021-03-31 (31 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 7,679
- Total persons involved: 16,259
- Total vehicles involved: 15,736
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/march-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: 2021-03-01 – 2021-03-31
Generated: June 1, 2026 · All rights reserved