I work from the counts, not from impressions. The South Dakota dataset covers August 2023 through October 2026, 39 months. In that window, inspectors logged 86,653 roadside inspections and recorded 70,403 violations, or 0.81 violations per inspection. Nationally, the same dataset shows 8,042,912 inspections and 12,865,241 violations, about 1.6 per inspection. On raw volume, South Dakota writes fewer violations per stop than the country as a whole.
The more useful number is the out-of-service share. South Dakota recorded 15,198 out-of-service violations out of 70,403, an OOS rate of 21.6%. The national figure is 2,268,984 out of 12,865,241, or 17.6%. A violation written in South Dakota is more likely to carry an out-of-service status than one written somewhere else. You can see the state's full breakdown on its state insights page.
Where the gap sits
Splitting the totals by category matters more than the headline rate, because the categories behave very differently.
- Vehicle: South Dakota recorded 15,425 vehicle violations, of which 11,022 were out-of-service, a share of 71.5%. Nationally, 1,703,633 of 7,100,282 vehicle violations were out-of-service, or 24.0%. This is the widest divergence in the data.
- Driver: South Dakota recorded 9,986 driver violations, with 4,176 out-of-service, or 41.8%. Nationally the share is 24.1% (565,351 of 2,344,141).
- Hazmat: South Dakota recorded 90 hazmat violations, 11 of them out-of-service, or 12.2%. Nationally it is 26.6% (15,088 of 56,752). The state sample is small enough that I would not build a conclusion on it.
The vehicle number is the one to sit with. An out-of-service status is assigned to an individual violation when the condition meets the out-of-service threshold, so a high share means inspectors were finding conditions that stop a vehicle, not that every truck in the state is unsafe. What the aggregate cannot tell you is which specific conditions drive the vehicle figure. That requires looking at violation-level detail, and it is the first place I would go if I were trying to explain this to a carrier.
Two denominators, two stories
The per-inspection figures point the other way at first glance. South Dakota recorded 15,198 out-of-service violations across 86,653 inspections, about 17.5 per 100 inspections. Nationally it is about 28.2 per 100 (2,268,984 across 8,042,912). Both are true, and they answer different questions.
Read together, the pattern is this: South Dakota inspectors wrote fewer violations per inspection, but a larger proportion of what they wrote was out-of-service. Per-inspection rates tell you how often a stop produces a problem. Per-violation shares tell you how serious the problems tend to be once they are written. A state can score low on one and high on the other, and if you only quote one, you will mislead people.
How to use these numbers
- Do not treat a state rate as a verdict on a carrier. Rates depend on what got inspected, the traffic mix, and how inspections are selected. Aggregate data cannot account for any of that.
- Check the category split before the headline. A 21.6% state rate hides a 71.5% vehicle share and a 12.2% hazmat share. Those are different problems with different fixes.
- Respect the time window. Thirty-nine months smooths out a lot, but a single quarter can look very different. Compare like windows when you track changes.
- Go to the regulation text, not the summary. The out-of-service criteria and the violation definitions live in the federal rules. The primary source is the eCFR for Title 49, and the FMCSA site hosts the program guidance.
Key takeaways
- South Dakota recorded 0.81 violations per inspection, versus about 1.6 nationally.
- Its out-of-service rate is 21.6%, versus 17.6% nationally.
- The widest gap is in vehicle violations: 71.5% out-of-service in South Dakota, 24.0% nationally.
- Per-inspection and per-violation figures tell different stories. Use both.
- Aggregate state data shows where to look. It does not tell you what happened on a specific stop.
If you run or dispatch in South Dakota, start with the state breakdown, then use the map to compare against neighboring states before drawing any conclusion about your own fleet.