What 393.30 means in plain language
FMCSR 393.30 comes down to one straightforward requirement: every battery on your commercial motor vehicle must be firmly mounted so it cannot shift, vibrate loose, or fall free during normal operation. If the battery box, hold-down bracket, tray, or securing hardware is missing, broken, or just worn out enough to let the battery move around, you're in violation.
The rule also covers how the battery is protected. Exposed terminals or a battery sitting uncovered in an area where they can contact metal — cab floors, frames, tool storage — creates a short-circuit and fire risk. The inspector isn't just looking for whether the battery starts the truck; they're checking whether it's mounted and covered so it stays safe while the truck is moving.
In practice, this usually shows up as a cracked or missing battery tray, a loose hold-down clamp, a missing vent cover, or a battery that visibly rocks when you press on it. None of those conditions are hard to spot during a pre-trip — which is exactly why inspectors write this citation when they find it.
What our enforcement data actually shows
Across our inspection database, 393.30 has generated 11,292 all-time citations, making it the #211 most-cited code out of 3,036 FMCSR codes. That puts it solidly in the upper tier of enforcement activity — this is not an obscure or rarely-checked item.
The most important number for a driver who just got cited: the out-of-service rate is 0.1%. Out of 11,292 all-time citations, only 12 vehicles were actually placed out of service. Compare that to the all-FMCSR average OOS rate of 31.4% — 393.30 is far below that threshold. In practical terms, the overwhelming majority of drivers cited for this code drove away after receiving the violation. That said, the citation still hits your CSA record with a severity weight of 3, and it still counts against your fleet's Vehicle Maintenance BASIC score.
Over the last 12 months, our records show 2,380 citations, and in just the last 90 days we logged 547 citations. That pace — roughly 180 citations per month — is consistent with a violation that inspectors actively look for during routine Level II and Level III inspections. The monthly trend data in our database shows volumes ranging from 177 to 258 citations per month over the past year, with no dramatic seasonal spike but a steady, persistent enforcement presence.
Who gets cited most
Looking at the last 180 days, Texas leads the country by a wide margin with 1,008 citations for 393.30. Illinois is a distant second at 55 citations, followed by Iowa at 37. North Carolina logged 29 citations and New Mexico 14 over the same period.
The OOS-rate difference across those top states is minimal — Texas shows a 0.2% OOS rate while Illinois, Iowa, North Carolina, and New Mexico all sit at 0.0%. That gap is not material enough to change your risk calculus based on which state you're operating in.
On the carrier side, our data shows fleets such as MARTIN SANCHEZ NEVAREZ (USDOT 3026535) with 18 all-time citations and JOSE LUIS VARELA REYES (USDOT 3719791) with 16 citations appearing near the top of the frequency list. High citation counts at any carrier are useful signals for fleet safety managers building inspection checklists — they indicate that battery securing may not be part of a consistent pre-trip protocol.
Looking at vehicle makes, our database shows Freightliner (FRHT) accounting for 2,155 all-time citations — by far the most of any make — followed by International (INTL) at 859 and Mack at 485. If your fleet runs predominantly Freightliner or International equipment, battery tray and hold-down condition deserves specific attention in your driver inspection training.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, 393.30 is a low-volume, low-OOS-rate code by comparison. Take 393.9(a) — Inoperable Required Lamps — which has accumulated 660,737 citations with a 15.4% OOS rate. That's nearly 59 times the citation volume of 393.30 and an OOS rate that is 154 times higher. Battery securing simply does not carry the same immediate safety consequence in inspectors' eyes as a lamp that is completely out.
Look at 396.3(a)(1) — the general inspection, repair, and maintenance code — and the contrast is even sharper: 236,919 citations and a 45.3% OOS rate. Inspectors writing that code are documenting systemic maintenance failures, and nearly half of those vehicles get parked. A 393.30 citation, with its 0.1% OOS rate, reflects a specific, fixable defect rather than a wholesale maintenance breakdown.
Even 393.11 — Lighting Devices/Reflectors — sits at 179,734 citations with a 1.8% OOS rate, still well above 393.30's rate. The pattern is clear: battery securing is enforced consistently but treated as a correctable condition rather than an immediate threat to vehicle safety by inspectors in the field.
How to avoid it
The co-occurring violation pattern in our 90-day data is telling. 393.30 shows up in the same inspections as inoperable required lamps (393.9, 197 shared inspections), windshield defects (393.78, 130 shared inspections), and missing emergency equipment (393.95A, 93 shared inspections). That pattern points to one root cause: pre-trip inspections that are either rushed or skipping the engine compartment and cab equipment checks entirely. A driver who misses a loose battery tray is usually the same driver who misses a burned-out marker lamp or a missing fire extinguisher.
- Open the hood and physically press on the battery. If it rocks or shifts at all, the hold-down is not doing its job. Check this every pre-trip, not just when you suspect a problem.
- Inspect the battery tray and bracket hardware. Cracks in plastic trays and corroded or missing clamp bolts are the most common reasons batteries come loose. If the tray is cracked or the bolt is finger-loose, document it and get it corrected before departure.
- Check terminal covers and vent caps. Exposed terminals on an unsecured battery are the combination that turns a minor violation into a fire. Make sure covers are in place and undamaged.
- On Freightliner and International equipment specifically, inspect the battery compartment door latches. Our data shows FRHT and INTL vehicles account for the majority of citations — on those platforms, worn door seals and loose tray hardware are common wear items that get overlooked.
- Use 393.30 as a bundled check with your lamp and extinguisher inspection. Given that inoperable lamps, missing fire extinguishers, and no proof of periodic inspection all co-occur heavily with this code, building one consolidated equipment-check habit during pre-trip will knock out multiple violation risks at once.
- Flag battery issues during post-trip as well. A battery that was secure when you left the yard may not be after a long haul over rough roads. Post-trip documentation of a loose hold-down creates a repair record and protects you from a citation on the next dispatch.