ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · IOWA, IA · DECEMBER 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/iowa/statewide/december-2021-report
Monthly Traffic Safety Analysis
5,150 CRASHES IN
IOWA, IA
DECEMBER 2021
In December 2021, Iowa recorded 5,150 traffic crashes, an 11.4% increase from the 4,622 crashes in December 2020. While total crashes rose, the number of fatalities decreased by 27% from 37 to 27 year-over-year. The most notable shift was a substantial 28.8% increase in total injuries, which rose from 1,201 in the prior period to 1,547 in the current period.
5,150
▲ 11.4%was 4,622
Total Crash Events
27
▼ -27.0%was 37
Persons Killed
1,547
▲ 28.8%was 1,201
Persons Injured
25
▼ -13.8%was 29
Fatal Crash Events
Note: "Persons Killed" (27) counts individual fatalities across all crash events. "Fatal" in the severity table below (25) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities.
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Overall, traffic crashes in Iowa showed a rising trend in December 2021 compared to the same month in 2020. The total number of crashes increased by 11.4%, from 4,622 to 5,150. This represents an absolute increase of 528 crashes year-over-year.
Vulnerable Road User Casualties
3
Pedestrians Killed
1
Cyclists Killed
23
Motorists Killed
0
Other Killed
28
Pedestrians Injured
10
Cyclists Injured
1,507
Motorists Injured
2
Other Injured
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)
When Crashes Happen
The temporal patterns of crashes shifted between December 2020 and December 2021. The peak day for crashes moved from Wednesday (802 crashes) in the prior period to Friday (1,002 crashes) in the current period. The peak hour for crashes remained consistent at 5 p.m. in both periods, though the volume of crashes during this hour increased from 540 to 615.
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Crash date field aggregated by weekday
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
The fatal crash rate decreased from 0.63% in December 2020 to 0.49% in December 2021. However, the proportion of crashes resulting in some form of injury increased. The share of crashes involving serious injuries grew from 1.4% to 2.0% year-over-year, and the combined share of all injury-related crashes (serious, minor, and possible) rose from 23.7% to 26.0%.
Severity is per crash event (most severe injury). 25 fatal crash events resulted in 27 persons killed.
Outcome by Severity (Crash Events)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · KABCO injury classification scale
Severity Distribution (Crash Events)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Most severe injury per crash record
Top Contributing Factors
Collisions with animals remained the top contributing factor in both periods, with a slight increase in count from 771 to 787 crashes. The ranking of other top factors shifted notably year-over-year. 'Followed too close' moved from the fourth to the second-ranked factor, with its crash count increasing by 59.7% from 310 to 495. Conversely, crashes attributed to 'Driving too fast for conditions' decreased from 415 to 396, dropping its rank from second to third.
Officer-Reported Primary Contributing Cause
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
The proportion of crashes occurring on dry roads and in clear weather increased in December 2021 compared to the prior year. Crashes on dry roads accounted for 58.3% of the total, up from 51.8%, while clear weather crashes rose from a 51.5% share to a 55.3% share. A notable shift occurred in winter-related road conditions: the share of crashes on snowy surfaces decreased from 14.2% to 5.4%, while the share on icy or frosty surfaces increased from 9.3% to 12.1%. The distribution of crashes by lighting conditions remained largely unchanged.
Weather
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Weather condition at time of crash
Lighting
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Lighting condition field
Road Surface
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Road surface condition field
Vehicles & Demographics
The top vehicle makes involved in crashes, Ford and Chevrolet, remained consistent in rank across both periods, with the count of vehicles for both makes increasing year-over-year. In terms of person demographics, the 35-44 age group (1,318 persons) became the largest cohort of people involved in crashes in December 2021. This displaced the 26-34 age group, which was the largest in the prior period with 1,667 persons.
Top Vehicle Makes (8,576 vehicles)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Vehicle unit records
1,003 persons with unknown or unrecorded age excluded from age chart.
Sex Distribution (5,621 persons with recorded sex)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-12-01 to 2021-12-31 · Person-level records linked to crash events
Data Sources & Methodology
Primary Data Source
All crash data in this report is sourced from Iowa Crash Data, accessed programmatically via the ArcGIS 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: ArcGIS 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: 2021-12-01 through 2021-12-31
- Report generated: September 9, 2026
Data Coverage
- Reporting period: 2021-12-01 through 2021-12-31 (31 days)
- Geographic scope: iowa, IA
- Total crash records analyzed: 5,150
- Total persons involved: 8,920
- Total vehicles involved: 8,576
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). "iowa, IA Crash Intelligence Report: December 2021." Published September 9, 2026. Reporting period: 2021-12-01 to 2021-12-31. Data source: Iowa Crash Data, ArcGIS Open Data. Available at: https://thatcarhitme.com/crash-data/iowa/statewide/december-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: Iowa Crash Data · ArcGIS
Period: 2021-12-01 – 2021-12-31
Generated: September 9, 2026 · All rights reserved