Monthly Traffic Safety Analysis

5,895 CRASHES IN
IOWA, IA
DECEMBER 2017

All metrics benchmarked againstDecember 2016

In December 2017, Iowa recorded 5,895 traffic crashes, a 2.7% decrease from the 6,060 crashes reported in December 2016. While overall crashes and fatalities declined, the most notable year-over-year shift occurred in contributing factors. Crashes attributed to 'Driving too fast for conditions' decreased by 24% in count, while collisions involving animals increased by 25%, becoming the leading factor in the current period.

5,895

-2.7%was 6,060

Total Crash Events

26

-29.7%was 37

Persons Killed

1,742

3.6%was 1,681

Persons Injured

24

-14.3%was 28

Fatal Crash Events

Note: "Persons Killed" (26) counts individual fatalities across all crash events. "Fatal" in the severity table below (24) counts crash events where at least one fatality occurred. A single crash can result in multiple fatalities.

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Aggregate counts from crash, person, and vehicle records

Trend Summary

Traffic collisions in December 2017 decreased compared to the same month in the prior year, with total crashes falling by 2.7% from 6,060 to 5,895. Despite the drop in total incidents, the number of reported injuries rose by 3.6% from 1,681 to 1,742. Conversely, fatalities saw a significant decrease, falling from 37 in December 2016 to 26 in December 2017.

Vulnerable Road User Casualties

3

Pedestrians Killed

Prior: 250.0%

0

Cyclists Killed

Prior: 00.0%

23

Motorists Killed

Prior: 35-34.3%

0

Other Killed

Prior: 00.0%

35

Pedestrians Injured

Prior: 342.9%

9

Cyclists Injured

Prior: 580.0%

1,697

Motorists Injured

Prior: 1,6393.5%

1

Other Injured

Prior: 3-66.7%

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)

When Crashes Happen

The temporal patterns of crashes remained highly consistent year-over-year, indicating stable weekly and daily traffic rhythms. In both December 2017 and December 2016, Friday was the peak day for crashes, with 1,367 and 1,233 incidents respectively. Similarly, the 5 p.m. hour was the single busiest time for collisions in both periods, recording 610 crashes in 2017 and 608 in 2016.

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Crash date field aggregated by weekday

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Crash time field aggregated by hour (0-23)

Crash Severity Breakdown

The fatal crash rate decreased from 0.46% of all crashes in December 2016 to 0.41% in December 2017. The total number of fatal crashes fell from 28 to 24. However, the proportion of crashes resulting in any level of injury (Serious, Minor, or Possible) saw a slight increase, rising from a combined 23.1% of all crashes in the prior period to 24.3% in the current period. Consequently, the share of non-injury crashes decreased from 76.5% to 75.2% of the total.

Severity is per crash event (most severe injury). 24 fatal crash events resulted in 26 persons killed.

Outcome by Severity (Crash Events)

Fatal24fatal crashes0.4%
-14.3%prior 28
Serious Injury87serious injury crashes1.5%
11.5%prior 78
Minor Injury427minor injury crashes7.2%
8.7%prior 393
Possible Injury922possible injury crashes15.6%
-0.4%prior 926
No Injury4,435no injury crashes75.2%
-4.3%prior 4,635

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · KABCO injury classification scale

Severity Distribution (Crash Events)

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Most severe injury per crash record

Top Contributing Factors

The ranking of leading contributing factors shifted between December 2016 and December 2017. 'Driving too fast for conditions,' the top factor in the prior period with 888 crashes, saw its count decrease by 24% to 675 crashes. Conversely, crashes involving an 'Animal' increased by 25% in count, rising from 621 to 776, making it the most common factor in December 2017. 'Followed too close' remained the third-ranked factor in both periods, with its count increasing slightly from 523 to 543.

Officer-Reported Primary Contributing Cause

Animal776 (13.2%)25.0%prior 621
Driving too fast for conditions675 (11.5%)-24.0%prior 888
Followed too close543 (9.2%)3.8%prior 523
Ran off road - left480 (8.1%)-15.0%prior 565
Lost Control415 (7%)-3.0%prior 428
Other (explain in narrative): Other369 (6.3%)28.1%prior 288
Ran off road - straight267 (4.5%)-2.9%prior 275
FTYROW: From stop sign244 (4.1%)-3.9%prior 254
FTYROW: Making left turn233 (4%)6.9%prior 218
Ran Traffic Signal177 (3%)4.1%prior 170

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Officer-reported primary contributory cause per crash

Road & Environmental Conditions

Crashes on dry roads were more prevalent in December 2017, accounting for 51.8% of all incidents compared to 40.1% in the previous year. Correspondingly, collisions on roads with ice or frost decreased significantly, dropping from 14.7% of the total in December 2016 to 8.0% in December 2017. The proportion of crashes occurring in clear weather also increased from 42.9% to 50.4%, suggesting better overall road and weather conditions during the current period.

Weather

Clear2,973 (56.4%)
14.2%prior 2,603
Cloudy1,099 (20.9%)
-14.0%prior 1,278
Snow867 (16.5%)
-17.2%prior 1,047
Freezing rain/drizzle122 (2.3%)
-55.8%prior 276
Blowing Snow82 (1.6%)
-34.9%prior 126
Rain70 (1.3%)
-5.4%prior 74
Severe Winds22 (0.4%)
83.3%prior 12
Other (explain in narrative)13 (0.2%)
18.2%prior 11
Fog, smoke, smog10 (0.2%)
-84.6%prior 65
Sleet, hail7 (0.1%)
-46.2%prior 13

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Weather condition at time of crash

Lighting

Daylight2,946 (55.7%)
-10.3%prior 3,283
Dark - roadway lighted1,182 (22.3%)
1.8%prior 1,161
Dark - roadway not lighted819 (15.5%)
9.3%prior 749
Dusk197 (3.7%)
4.2%prior 189
Dawn114 (2.2%)
0.0%prior 114
Dark - unknown roadway lighting31 (0.6%)
14.8%prior 27

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Lighting condition field

Road Surface

Dry3,056 (57.9%)
25.9%prior 2,428
Snow1,224 (23.2%)
-2.1%prior 1,250
Ice/frost473 (9.0%)
-47.0%prior 892
Wet318 (6.0%)
-51.8%prior 660
Slush114 (2.2%)
-47.9%prior 219
Gravel79 (1.5%)
71.7%prior 46
Other (explain in narrative)10 (0.2%)
-9.1%prior 11
Mud, dirt2 (0.0%)
Sand1 (0.0%)

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Road surface condition field

Vehicles & Demographics

The vehicle makes most frequently involved in crashes remained broadly similar, with Chevrolet and Ford being the top two in both periods. In December 2017, Toyota-branded vehicles were involved in 748 crashes, surpassing Dodge-branded vehicles (676 crashes) for the third spot, a reversal from the prior year. An analysis of persons involved shows a general decrease across most age groups, with the largest reductions in the 16-20 and 45-54 age brackets. The number of individuals aged 65 and older involved in crashes saw a slight increase from 1,008 to 1,063.

Top Vehicle Makes (9,920 vehicles)

1
FORD1,574 (15.9%)
-9.3%prior 1,735
2
CHEV1,375 (13.9%)
26.0%prior 1,091
3
CHEVROLET635 (6.4%)
-40.6%prior 1,069
4
TOYT494 (5%)
19.6%prior 413
5
DODG432 (4.4%)
35.4%prior 319
6
JEEP346 (3.5%)
4.2%prior 332
7
HOND312 (3.1%)
11.0%prior 281
8
GMC305 (3.1%)
-7.0%prior 328
9
CHRY273 (2.8%)
70.6%prior 160
10
TOYOTA254 (2.6%)
-21.4%prior 323

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · Vehicle unit records

1,146 persons with unknown or unrecorded age excluded from age chart.

Sex Distribution (6,753 persons with recorded sex)

Male3,891 (57.6%)
-13.2%prior 4,483
Female2,862 (42.4%)
-12.6%prior 3,274

Source: Iowa Crash Data · ArcGIS Open Data · 2017-12-01 to 2017-12-31 · 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: 2017-12-01 through 2017-12-31
  • Report generated: September 9, 2026

Data Coverage

  • Reporting period: 2017-12-01 through 2017-12-31 (31 days)
  • Geographic scope: iowa, IA
  • Total crash records analyzed: 5,895
  • Total persons involved: 10,351
  • Total vehicles involved: 9,920

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 2017." Published September 9, 2026. Reporting period: 2017-12-01 to 2017-12-31. Data source: Iowa Crash Data, ArcGIS Open Data. Available at: https://thatcarhitme.com/crash-data/iowa/statewide/december-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

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