I pull state-level roadside data for VioCodes because one state's number means little until you set it against the national baseline and split it into parts. Maine is a useful case. Between August 2023 and October 2026, the data I'm working from covers 43,458 inspections in Maine, which produced 41,308 recorded violations. You can see the same breakdown on the Maine roadside insights page.
What the headline rate measures
Maine's out-of-service rate is 23.4%, compared with 17.6% nationally. That figure is easy to misread. It is not the share of trucks pulled off the road. It is the share of violations that were out-of-service. Maine recorded 9,650 out-of-service violations out of 41,308 total violations, which is where the 23.4% comes from.
Looked at per inspection, the picture is the same: Maine averages 0.95 violations per inspection, and produces 22.2 out-of-service violations for every 100 inspections.
Both measures matter. The first tells you how severe the violations are on average. The second tells you how often an inspector finds something that stops the truck.
Vehicles carry most of the load
The data splits violations into vehicle, driver, and hazardous materials categories. The vehicle category accounts for 29,266 violations and 6,989 out-of-service violations. The driver category accounts for 11,128 violations and 2,661 out-of-service violations. Hazardous materials accounts for 262 violations and 68 out-of-service violations.
Put in shares, vehicles are about 71% of all violations and about 72% of out-of-service violations. Drivers are about 27% of violations and about 28% of out-of-service violations.
Mechanically, this makes sense. Many vehicle findings are physical defects an inspector can confirm on the spot: brakes, lamps, tires, couplings. When a defect meets the out-of-service threshold, the truck stops there. Driver findings often depend on records, such as hours or licensing, and those tend to be checkable but are less often the thing that strands a load on the roadside.
I want to be careful with the category numbers. The vehicle, driver, and hazmat counts do not add up exactly to the headline totals, and the out-of-service counts across categories slightly exceed the state's headline out-of-service figure. I read them as overlapping slices, not a clean partition. That means I can say vehicles carry most of the volume, but I would not claim from this data alone that vehicles explain the entire gap between Maine and the national rate.
Why the gap is hard to pin down from one number
Three things limit what a single state rate can tell you.
First, the window is 39 months, from August 2023 through October 2026. That is long enough to smooth out a single bad quarter, but it still blends enforcement patterns, inspector mix, and carrier mix together.
Second, the rate describes inspections, not carriers. A high out-of-service share in a state can reflect where inspectors focus, what kinds of carriers run through the state, and how many inspections are truck-specific versus driver-focused. None of that is visible in a headline ratio.
Third, violations per inspection (0.95) is an average. A state can look ordinary on that average and still have a narrow set of defects that drive most of the stops.
What to do with this
If you run trucks through Maine, the practical reading is that the vehicle side is where the out-of-service exposure concentrates. A pre-trip and post-trip routine that checks brakes, lighting, tires, and connection points will catch more of what stops trucks than a paperwork review alone. Driver records still need to be clean, but the numbers suggest the roadside stop is more often decided by equipment condition.
The federal out-of-service rules that govern these decisions are published in Title 49 of the Code of Federal Regulations. Read the regulation itself before you rely on any summary, including mine.
Key takeaways
- Maine's out-of-service rate is 23.4% of violations, versus 17.6% nationally, across 39 months of data.
- Vehicles account for about 71% of violations and about 72% of out-of-service violations in the Maine data.
- The category counts overlap and do not sum cleanly, so treat the vehicle conclusion as a pattern, not a precise attribution.
- A state rate describes inspections, not individual carriers. Use it as a baseline, then check your own inspection history against it.
If you want to compare Maine against other states on the same measures, the state map lets you move between them without rebuilding the comparison by hand.