Yearly Traffic Safety Analysis

2,583 CRASHES IN
IOWA, IA
2018

All metrics benchmarked against2017

In 2018, Johnson County recorded 2,583 total traffic crashes, a slight decrease of 0.7% from the 2,602 crashes reported in 2017. While overall crashes remained stable, the number of fatal crashes fell from 8 to 5, and total injuries decreased from 738 to 706. One of the most notable shifts was a 36.8% increase in the count of crashes attributed to 'Driving too fast for conditions,' which rose from 163 incidents in 2017 to 223 in 2018.

2,583

▼ -0.7%was 2,602

Total Crash Events

7

▼ -12.5%was 8

Persons Killed

706

▼ -4.3%was 738

Persons Injured

5

▼ -37.5%was 8

Fatal Crash Events

Note: "Persons Killed" (7) 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.

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Aggregate counts from crash, person, and vehicle records

Trend Summary

Overall crash trends in Johnson County showed a slight decline from 2017 to 2018. The total number of crashes decreased by 19 incidents from 2,602 to 2,583. The human impact of these crashes also saw a reduction, with total injuries falling by 4.3% from 738 to 706 and total fatalities decreasing from 8 to 7.

Vulnerable Road User Casualties

1

Pedestrians Killed

Prior: 1→0.0%

0

Cyclists Killed

Prior: 0→0.0%

6

Motorists Killed

Prior: 7↓-14.3%

0

Other Killed

Prior: 0→0.0%

28

Pedestrians Injured

Prior: 30↓-6.7%

38

Cyclists Injured

Prior: 32↑18.8%

638

Motorists Injured

Prior: 673↓-5.2%

2

Other Injured

Prior: 3↓-33.3%

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Mode classified from person records (driver/passenger → motorist; pedestrian; bicyclist → cyclist; in-line skater / unspecified → other)

When Crashes Happen

The temporal patterns of crashes in Johnson County remained largely consistent year-over-year, with Friday being the peak day and 5 p.m. being the peak hour in both periods. In 2018, Friday saw 470 crashes, down from 515 in 2017, while the 5 p.m. hour had 259 crashes, nearly identical to the 260 recorded in the prior year. A minor shift occurred in weekday patterns, as Tuesday became the second-busiest day for crashes in 2018 with 419 incidents, replacing Thursday from 2017.

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Crash date field aggregated by weekday

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Crash time field aggregated by hour (0-23)

Crash Severity Breakdown

The severity of crashes saw a notable improvement in 2018 compared to 2017. The number of fatal crashes decreased from 8 to 5, causing the fatal crash rate to fall from 0.31% to 0.19% of all crashes. Crashes resulting in serious injuries also declined, dropping from 43 incidents in 2017 to 35 in 2018. In contrast, crashes classified with minor injuries increased in both count, from 202 to 224, and share, from 7.8% to 8.7% of all incidents.

Severity is per crash event (most severe injury). 5 fatal crash events resulted in 7 persons killed.

Outcome by Severity (Crash Events)

Fatal5fatal crashes0.2%
↓-37.5%prior 8
Serious Injury35serious injury crashes1.4%
↓-18.6%prior 43
Minor Injury224minor injury crashes8.7%
↑10.9%prior 202
Possible Injury365possible injury crashes14.1%
↓-6.2%prior 389
No Injury1,954no injury crashes75.6%
↓-0.3%prior 1,960

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · KABCO injury classification scale

Severity Distribution (Crash Events)

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Most severe injury per crash record

Top Contributing Factors

The leading contributing factors for crashes showed some significant shifts between 2017 and 2018. Although 'Followed too close' remained the top factor, its count decreased from 514 to 479. The most notable change was in 'Driving too fast for conditions,' which rose from the third-ranked factor to the second as its incident count increased by 36.8% from 163 to 223. Another significant increase was observed in crashes where a driver 'Ran off road - left,' which grew in count from 98 to 151.

Officer-Reported Primary Contributing Cause

Followed too close479 (18.5%)↓-6.8%prior 514
Driving too fast for conditions223 (8.6%)↑36.8%prior 163
Other (explain in narrative): Other186 (7.2%)↓-3.1%prior 192
Animal168 (6.5%)↑4.3%prior 161
Ran off road - left151 (5.8%)↑54.1%prior 98
FTYROW: From stop sign112 (4.3%)↓-18.8%prior 138
Improper or erratic lane changing102 (3.9%)↓-2.9%prior 105
FTYROW: Making left turn92 (3.6%)↓-7.1%prior 99
Made improper turn74 (2.9%)↓-23.7%prior 97
FTYROW: From driveway65 (2.5%)↑20.4%prior 54

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Officer-reported primary contributory cause per crash

Road & Environmental Conditions

While most crashes in both years occurred in clear weather and daylight, there was a significant shift related to road surface conditions. In 2018, the proportion of crashes on dry roads decreased to 67.6% from 76.2% in 2017. Correspondingly, crashes on snowy or icy surfaces more than doubled, increasing from a combined 128 incidents in 2017 to 291 in 2018. Crashes during daylight hours remained the dominant condition, accounting for approximately 71% of all incidents in both periods.

Weather

Clear1,513 (61.0%)
↓-2.9%prior 1,558
Cloudy570 (23.0%)
↓-5.8%prior 605
Rain170 (6.9%)
↓-17.9%prior 207
Snow134 (5.4%)
↑83.6%prior 73
Freezing rain/drizzle58 (2.3%)
↑163.6%prior 22
Blowing Snow12 (0.5%)
↑71.4%prior 7
Fog, smoke, smog10 (0.4%)
↓-61.5%prior 26
Sleet, hail7 (0.3%)
Other (explain in narrative)6 (0.2%)
Blowing sand, soil, dirt1 (0.0%)

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Weather condition at time of crash

Lighting

Daylight1,826 (73.5%)
↓-2.1%prior 1,866
Dark - roadway lighted302 (12.2%)
↑0.3%prior 301
Dark - roadway not lighted233 (9.4%)
↓-4.1%prior 243
Dusk70 (2.8%)
↑11.1%prior 63
Dawn43 (1.7%)
↑13.2%prior 38
Dark - unknown roadway lighting11 (0.4%)
↑37.5%prior 8

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Lighting condition field

Road Surface

Dry1,746 (70.3%)
↓-12.0%prior 1,983
Wet387 (15.6%)
↑3.2%prior 375
Snow195 (7.9%)
↑114.3%prior 91
Ice/frost96 (3.9%)
↑159.5%prior 37
Slush33 (1.3%)
Gravel15 (0.6%)
↓-6.3%prior 16
Other (explain in narrative)5 (0.2%)
Sand3 (0.1%)
Mud, dirt3 (0.1%)
Oil1 (0.0%)

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Road surface condition field

Vehicles & Demographics

The makes of vehicles involved in crashes remained consistent year-over-year, with Ford, Chevrolet, and Toyota being the most common in both 2018 and 2017. The number of Ford vehicles involved decreased from 688 to 608, while Chevrolet and Toyota counts were relatively stable. The age demographics of people involved in crashes also showed little change; the 26-34 age group was the largest cohort in both periods, accounting for 903 individuals in 2018 and 896 in 2017.

Top Vehicle Makes (4,776 vehicles)

1
FORD608 (12.7%)
↓-11.6%prior 688
2
CHEV473 (9.9%)
↑4.9%prior 451
3
TOYT448 (9.4%)
↑0.2%prior 447
4
HOND281 (5.9%)
↑1.1%prior 278
5
CHEVROLET184 (3.9%)
↓-25.8%prior 248
6
TOYOTA177 (3.7%)
↓-4.3%prior 185
7
DODG168 (3.5%)
↑21.7%prior 138
8
NISS152 (3.2%)
↑8.6%prior 140
9
JEEP144 (3%)
↑1.4%prior 142
10
NR134 (2.8%)
↑6.3%prior 126

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · Vehicle unit records

637 persons with unknown or unrecorded age excluded from age chart.

Sex Distribution (3,877 persons with recorded sex)

Male2,108 (54.4%)
↓-2.2%prior 2,155
Female1,769 (45.6%)
↓-3.1%prior 1,825

Source: Iowa Crash Data · ArcGIS Open Data · 2018-01-01 to 2018-12-31 · 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: 2018-01-01 through 2018-12-31
  • Report generated: September 9, 2026

Data Coverage

  • Reporting period: 2018-01-01 through 2018-12-31 (365 days)
  • Geographic scope: iowa, IA
  • Total crash records analyzed: 2,583
  • Total persons involved: 5,462
  • Total vehicles involved: 4,776

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: 2018." Published September 9, 2026. Reporting period: 2018-01-01 to 2018-12-31. Data source: Iowa Crash Data, ArcGIS Open Data. Available at: https://thatcarhitme.com/crash-data/iowa/statewide/2018-annual-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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