A dispatcher asked me last month what "out-of-service rate" means, and the answer he got from a forum was "your chance of getting parked." That is close but wrong in a way that matters. So before comparing states, I want to pin down the arithmetic.
Across the 39 months from August 2023 through October 2026, Tennessee recorded 248,343 roadside inspections. Those inspections produced 209,926 violations, and 80,864 of those violations were out-of-service. The state-level detail lives on the Tennessee insights page.
How the out-of-service rate is built
The headline figure for Tennessee is 38.5. That is out-of-service violations divided by total violations (80,864 out of 209,926), not out-of-service inspections divided by inspections. The distinction matters when you read a state profile, because it measures how often a violation written during an inspection carried an out-of-service status, not how often a truck was stopped.
The national comparison uses the same method: 2,265,247 out-of-service violations out of 12,832,668 total, for a rate of 17.7. Tennessee's rate is roughly 2.2 times that.
Two other ratios help separate volume from severity. Per inspection, Tennessee wrote about 0.85 violations (209,926 divided by 248,343). Nationally the figure is about 1.60 (12,832,668 divided by 8,023,075). Tennessee's inspections produce fewer violations each, yet out-of-service items show up at a higher rate: about 32.6 per 100 inspections in Tennessee against about 28.2 nationally.
So the pattern is not "Tennessee inspectors write more tickets." It is closer to "when something is written in Tennessee, it is more likely to hold the vehicle or driver." Why that happens is not something this dataset explains. Inspection mix, the level of inspection performed, local enforcement emphasis, and carrier population all could contribute. I would not state a cause without the inspection-level records.
Where the data gets messy
I want to be direct about a problem I found while preparing this. The category splits for Tennessee do not reconcile with the totals:
- Driver violations (39,034), vehicle violations (60,604), and hazmat violations (341) add up to 99,979. That is about half of the 209,926 total.
- Vehicle out-of-service items (62,633) exceed vehicle violations (60,604). If out-of-service status is a subset of the violations it attaches to, that cannot happen.
Until the source's categorization is confirmed, I will not draw conclusions from the driver-versus-vehicle breakdown. The totals and the overall out-of-service rate are internally consistent enough to discuss. The category splits are not yet. If you see a Tennessee breakdown that claims a clear driver-side or vehicle-side story, check whether the numbers add up before you repeat it.
The hazmat figures are smaller but cleaner: 341 violations, 113 of them out-of-service. That is a useful signal for carriers hauling regulated loads, though a sample of that size shifts quickly with a few inspections.
What a carrier can do with this
The rules behind these inspections sit in federal regulation. The inspection, repair, and maintenance requirements are in 49 CFR Part 396 on eCFR, and reading the text beats relying on anyone's summary, including mine.
For a practical read:
- Pull your own inspection history for the last 12 to 24 months. Note which violations were written, where, and whether they carried out-of-service status.
- Compare your results against the state profile for the lanes you actually run. A state rate tells you the environment; your own history tells you what you control.
- Treat repeat violation types as a process problem, not bad luck. If the same item shows up at different inspections, the pre-trip or maintenance routine is missing it.
Key takeaways
- Tennessee's 38.5 out-of-service rate is out-of-service violations divided by total violations, not out-of-service inspections divided by inspections.
- The national comparison is 17.7 on the same basis, so Tennessee sits about 2.2 times higher.
- Tennessee writes fewer violations per inspection (about 0.85) than the national figure (about 1.60), but more of them carry out-of-service status.
- The driver, vehicle, and hazmat category splits do not reconcile with the totals, so do not build a story on them yet.
- Your own inspection history is a better guide to your risk than any state average.
If you want to see how Tennessee's pattern compares with other states, the full insights index lays out the same metrics across the dataset.