ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · CHICAGO, IL · OCTOBER 2017
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/october-2017-report
Monthly Traffic Safety Analysis
10,022 CRASHES IN
CHICAGO, IL
OCTOBER 2017
Total crashes in October 2017 reached 10022, marking a substantial 100.64% increase from the 4995 crashes reported in October 2016. This significant rise in overall crash volume represents the most notable year-over-year shift. Fatalities also increased by 66.67%, from 3 to 5, while injuries surged by 329.64%, from 479 to 2058.
10,022
▲ 100.6%was 4,995
Total Crash Events
5
▲ 66.7%was 3
Persons Killed
2,058
▲ 329.6%was 479
Persons Injured
2,484
▲ 96.4%was 1,265
Hit-and-Run Crashes
Note: "Persons Killed" (5) counts individual fatalities across all crash events. "Fatal" in the severity table below (4) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities. 25 crashes with unreported severity are not shown in the severity breakdown.
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Aggregate counts from crash, person, and vehicle records
Trend Summary
The overall trend indicates a sharp increase in crash activity year-over-year. Total crashes more than doubled, rising from 4995 in October 2016 to 10022 in October 2017, representing a 100.64% increase. Both fatalities and injuries also saw significant increases during this period, indicating a worsening safety trend.
2,484
Hit-and-Run Crashes — October 2017
▲ 96.4% vs prior (1,265)
The number of hit-and-run crashes increased from 1265 in October 2016 to 2484 in October 2017. However, the overall hit-and-run rate slightly decreased from 25.3% of total crashes in the prior period to 24.8% in the current period.
Vulnerable Road User Casualties
0
Pedestrians Killed
0
Cyclists Killed
5
Motorists Killed
0
Other Killed
304
Pedestrians Injured
160
Cyclists Injured
1,593
Motorists Injured
1
Other Injured
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · 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 October 2016 (782 crashes) to Tuesday in October 2017 (1804 crashes). Despite this, the peak hour for crashes remained consistent at 3 p.m. in both periods, with the number of crashes at this hour increasing from 406 to 776.
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Crash date field aggregated by weekday
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The fatal crash rate decreased from 0.06% in October 2016 to 0.04% in October 2017, despite an increase in the absolute number of fatal crashes from 3 to 4. The proportion of crashes resulting in any injury (Serious, Minor, or Possible) significantly increased from 7% to 15.3% of total crashes year-over-year.
Severity is per crash event (most severe injury). 4 fatal crash events resulted in 5 persons killed.
Outcome by Severity (Crash Events)
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · KABCO injury classification scale
Severity Distribution
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Most severe injury per crash record
Top Contributing Factors
The leading contributing factors saw substantial increases in count, with 'FAILING TO YIELD RIGHT-OF-WAY' rising by 806 crashes (159.29%) from 506 to 1312, becoming the top factor. 'FOLLOWING TOO CLOSELY' also increased by 534 crashes (87.83%), from 608 to 1142, moving to the second position. 'IMPROPER OVERTAKING/PASSING' increased by 163 crashes (53.1%), from 307 to 470.
Officer-Reported Primary Contributing Cause
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
The proportion of crashes occurring in rainy weather conditions notably increased from 11.75% in October 2016 to 22.73% in October 2017. Similarly, crashes on wet road surfaces saw a significant proportional rise, from 14.17% to 25.33% year-over-year. Daylight conditions continued to account for the majority of crashes in both periods.
Weather
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Weather condition at time of crash
Lighting
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Lighting condition field
Road Surface
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Road surface condition field
Vehicles & Demographics
The top three vehicle makes involved in crashes—Chevrolet, Toyota, and Ford—remained consistent across both periods, all experiencing increased counts in line with the overall rise in crashes. The age distribution of persons involved in crashes showed the 26-34 age group consistently having the highest representation, with their proportional involvement remaining relatively stable despite increased raw numbers.
Top Vehicle Makes (20,458 vehicles)
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Vehicle unit records
6,264 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 (22,080 persons with recorded sex)
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · Person-level records linked to crash events
Speed Limit Zones
The 30 mph speed limit zone continued to account for the largest share of crashes, increasing from 3784 to 7569 crashes year-over-year. The fatal crash rate within the 30 mph zone remained unchanged at 0.053% in both periods. The 35 mph zone saw its fatal crash rate decrease from 0.369% to 0%.
Fatal crashes by zone: 30 mph: 4 of 7,569 (0.053%)
Source: Chicago Traffic Crashes · Socrata Open Data · 2017-10-01 to 2017-10-31 · 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: 2017-10-01 through 2017-10-31
- Report generated: June 1, 2026
Data Coverage
- Reporting period: 2017-10-01 through 2017-10-31 (31 days)
- Geographic scope: Chicago, IL
- Total crash records analyzed: 10,022
- Total persons involved: 22,462
- Total vehicles involved: 20,458
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/october-2017-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: 2017-10-01 – 2017-10-31
Generated: June 1, 2026 · All rights reserved