ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · DECEMBER 2019
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/december-2019-report
Monthly Traffic Safety Analysis
9,418 CRASHES IN
CHICAGO, IL
DECEMBER 2019
In December 2019, Chicago experienced a decrease in total crashes compared to December 2018, with 9,418 crashes reported, down from 10,021, representing a 6.0% reduction. The most notable year-over-year shift was a 50.0% decrease in total fatalities, falling from 10 to 5. Total injuries also saw a significant decline, decreasing by 13.8% from 1,902 to 1,640.
9,418
▼ -6.0%was 10,021
Total Crash Events
5
▼ -50.0%was 10
Persons Killed
1,640
▼ -13.8%was 1,902
Persons Injured
2,675
▼ -4.8%was 2,809
Hit-and-Run Crashes
Note: "Persons Killed" (5) counts individual fatalities across all crash events. "Fatal" in the severity table below (5) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 22 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall, crash data for December 2019 indicates a downward trend in traffic incidents compared to the prior year. Total crashes decreased by 603, or 6.0%, from 10,021 in December 2018 to 9,418 in December 2019. This decline was accompanied by a 50.0% reduction in total fatalities, which fell from 10 to 5.
2,675
Hit-and-Run Crashes — December 2019
▼ -4.8% vs prior (2,809)
The total number of hit-and-run crashes decreased by 134 (4.8% in count), falling from 2,809 in December 2018 to 2,675 in December 2019. Despite this reduction in raw numbers, the overall hit-and-run rate slightly increased from 28.0% of total crashes in December 2018 to 28.4% in December 2019.
Vulnerable Road User Casualties
0
Pedestrians Killed
0
Cyclists Killed
5
Motorists Killed
277
Pedestrians Injured
51
Cyclists Injured
1,312
Motorists Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · 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 December 2018, with 1,730 crashes, to Tuesday in December 2019, with 1,582 crashes. While the peak hour remained 5 PM for both periods, the number of crashes at this hour decreased from 788 in December 2018 to 723 in December 2019. Notably, Tuesday saw a 37.8% increase in crashes, rising by 434 from 1,148 to 1,582, whereas Saturday experienced a 28.8% decrease, falling by 499 from 1,730 to 1,231.
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The overall fatal crash rate decreased from 0.09% in December 2018 to 0.05% in December 2019. Total fatalities saw a 50.0% reduction, dropping from 10 to 5, while total injuries decreased by 13.8% from 1,902 to 1,640. Serious injury crashes (severity 'A') decreased by 7.1% in count, from 170 to 158, and minor injury crashes (severity 'B') decreased by 12.9% in count, from 796 to 693.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Most severe injury per crash record
Top Contributing Factors
The top contributing factor, 'FAILING TO YIELD RIGHT-OF-WAY,' decreased by 130 crashes (10.7% in count) from 1,218 to 1,088. 'FOLLOWING TOO CLOSELY' also saw a decrease of 64 crashes (6.2% in count), falling from 1,035 to 971. 'FAILING TO REDUCE SPEED TO AVOID CRASH' increased by 11 crashes (2.3% in count) from 469 to 480, moving it into the top three factors for December 2019. The factor 'WEATHER' experienced a significant 58.8% decrease in count, dropping from 228 to 94 crashes.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
There was a notable decrease in crashes occurring under adverse weather conditions in December 2019 compared to the prior year. Crashes during 'RAIN' decreased by 65.1% in count (from 1,347 to 470), and those during 'SNOW' decreased by 29.5% in count (from 407 to 287). Similarly, crashes on 'WET' road surfaces decreased by 50.8% in count (from 2,114 to 1,039), and on 'ICE' surfaces by 68.8% in count (from 170 to 53).
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Road surface condition field
Vehicles & Demographics
The total number of vehicles involved in crashes decreased by 4.6%, from 20,384 in December 2018 to 19,439 in December 2019. The count of 'DRIVER' type vehicles decreased by 912, from 17,265 to 16,353. Among top vehicle makes, Chevrolet, Toyota, and Honda all experienced decreases in crash involvement counts, while Nissan saw a slight increase of 44 vehicles, rising from 1,666 to 1,710. The overall number of persons involved in crashes decreased by 6.4%, from 22,483 to 21,036, with all reported age groups showing a reduction in person counts.
Top Vehicle Makes (19,439 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Vehicle unit records
6,060 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 (20,646 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · Person-level records linked to crash events
Speed Limit Zones
Crashes occurring in 30 mph speed zones decreased by 702 (9.2% in count) from 7,666 to 6,964, and fatalities in these zones saw a substantial reduction from 8 to 2. Conversely, crashes in 25 mph zones increased slightly by 10 (1.8% in count) from 562 to 572, with fatalities in this zone doubling from 1 to 2. The 5 mph speed zone, which had no fatalities in December 2018, recorded 1 fatality out of 31 crashes in December 2019, resulting in a fatal rate of 3.226% for that zone.
Fatal crashes by zone: 5 mph: 1 of 31 (3.226%) · 25 mph: 2 of 572 (0.35%) · 30 mph: 2 of 6,964 (0.029%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2019-12-01 to 2019-12-31 · 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: 2019-12-01 through 2019-12-31
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2019-12-01 through 2019-12-31 (31 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 9,418
- Total persons involved: 21,036
- Total vehicles involved: 19,439
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/december-2019-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: 2019-12-01 – 2019-12-31
Generated: June 1, 2026 · All rights reserved