ThatCarHitMe.com
An Injuria.ai Company
YEAR-OVER-YEAR CRASH REPORT · IOWA, IA · SEPTEMBER 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/september-2021-report
Monthly Traffic Safety Analysis
4,536 CRASHES IN
IOWA, IA
SEPTEMBER 2021
In September 2021, Iowa recorded 4,536 total traffic crashes, a 9.5% increase from the 4,143 crashes reported in September 2020. While overall collisions rose, the number of fatalities slightly decreased from 41 to 38 year-over-year. The most significant trend was the overall rise in crash volume across the state.
4,536
▲ 9.5%was 4,143
Total Crash Events
38
▼ -7.3%was 41
Persons Killed
1,513
▼ -1.6%was 1,538
Persons Injured
35
▼ -12.5%was 40
Fatal Crash Events
Note: "Persons Killed" (38) counts individual fatalities across all crash events. "Fatal" in the severity table below (35) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities.
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Aggregate counts from crash, person, and vehicle records
Trend Summary
Crash trends in September 2021 showed a notable increase in total collisions compared to the same month in the prior year. Total crashes rose by 9.5%, from 4,143 to 4,536. Despite this increase in crash volume, both total injuries and fatalities saw slight decreases, falling by 1.6% and 7.3% respectively.
Vulnerable Road User Casualties
2
Pedestrians Killed
3
Cyclists Killed
33
Motorists Killed
0
Other Killed
37
Pedestrians Injured
41
Cyclists Injured
1,424
Motorists Injured
11
Other Injured
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · 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 September 2020 and September 2021. The peak day for crashes moved from Tuesday (743 crashes) in the prior year to Thursday (847 crashes) in the current period. While the peak hour for collisions remained at 3 p.m. year-over-year, the number of crashes during this hour increased from 348 to 404.
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Crash date field aggregated by weekday
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Crash time field aggregated by hour (0-23)
Crash Severity Breakdown
While total crashes increased, the severity of those crashes showed a slight downward trend year-over-year. The fatal crash rate decreased from 0.97 per 100 crashes in September 2020 to 0.77 in September 2021, with fatal crashes dropping from 40 to 35. The proportion of crashes resulting in possible injury also decreased from 17.0% to 15.6% of all incidents. Conversely, the share of crashes with no reported injuries increased from 68.2% to 70.0%.
Severity is per crash event (most severe injury). 35 fatal crash events resulted in 38 persons killed.
Outcome by Severity (Crash Events)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · KABCO injury classification scale
Severity Distribution (Crash Events)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Most severe injury per crash record
Top Contributing Factors
The leading contributing factors shifted between the two periods. In September 2021, 'Followed too close' became the primary factor with 548 incidents, an increase of 98 crashes (a 21.8% count increase) from 450 in the prior year when it was ranked second. 'Animal' involvement, the top factor in 2020 with 503 crashes, saw a slight increase to 516 crashes but moved to the second position. Other notable changes include an increase in crashes attributed to 'Ran Traffic Signal,' which rose from 124 to 157 incidents, and a decrease in 'Ran off road - left' crashes from 271 to 228.
Officer-Reported Primary Contributing Cause
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Officer-reported primary contributory cause per crash
Road & Environmental Conditions
Crashes in September 2021 occurred under more favorable conditions compared to the same month in 2020. The proportion of crashes happening in clear weather increased from 64.0% to 77.3% of the total. Correspondingly, crashes during rain fell from a 10.8% share to 2.9%. A similar trend was observed for road surface conditions, with the percentage of crashes on wet surfaces decreasing from 16.3% in 2020 to 4.8% in 2021.
Weather
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Weather condition at time of crash
Lighting
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Lighting condition field
Road Surface
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Road surface condition field
Vehicles & Demographics
The demographic profile of vehicles and persons involved in crashes remained largely stable year-over-year. The most common vehicle makes involved in collisions were consistent, with Ford and Chevrolet models leading in both September 2020 and September 2021. Similarly, the age distribution of all persons involved in crashes saw minimal change; the 26-34 age group constituted the largest single cohort in both periods, representing 14.7% of individuals in 2020 and 15.0% in 2021.
Top Vehicle Makes (7,978 vehicles)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · Vehicle unit records
1,272 persons with unknown or unrecorded age excluded from age chart.
Sex Distribution (6,226 persons with recorded sex)
Source: Iowa Crash Data · ArcGIS Open Data · 2021-09-01 to 2021-09-30 · 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: 2021-09-01 through 2021-09-30
- Report generated: September 9, 2026
Data Coverage
- Reporting period: 2021-09-01 through 2021-09-30 (30 days)
- Geographic scope: iowa, IA
- Total crash records analyzed: 4,536
- Total persons involved: 9,544
- Total vehicles involved: 7,978
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: September 2021." Published September 9, 2026. Reporting period: 2021-09-01 to 2021-09-30. Data source: Iowa Crash Data, ArcGIS Open Data. Available at: https://thatcarhitme.com/crash-data/iowa/statewide/september-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: 2021-09-01 – 2021-09-30
Generated: September 9, 2026 · All rights reserved