What 172.325(a) means in plain language
When you're transporting materials that are heated to an elevated temperature—such as asphalt, molten metals, or other thermally conditioned cargo—those materials must be clearly marked with a "Hot" label or marking. This requirement exists because elevated temperature materials pose a burn hazard and other safety risks to anyone who might come into contact with the vehicle or its load during transport, inspection, or unloading.
The regulation requires that the marking be visible and legible so that any person approaching the vehicle—whether a law enforcement officer, fellow driver, shipper, or receiver—immediately understands that the cargo presents a thermal hazard. A missing or illegible "Hot" marking defeats this safety communication and creates the conditions for an inspection citation.
What our enforcement data actually shows
Across our 13 million+ roadside inspection records, 172.325(a) citations are exceptionally rare. All-time, we see only 9 citations for this code, with zero citations in the last 12 months and zero in the last 90 days. This code ranks #2230 of 3,036 FMCSR codes by citation volume.
What stands out most: the out-of-service rate is 0.0%. None of the 9 drivers cited for this violation were placed out of service. For context, the all-FMCSR average OOS rate is 31.4%, so this code sits dramatically below the enforcement severity baseline. This suggests inspectors treat a missing "Hot" marking as a correctable paperwork or labeling issue rather than an immediate safety threat that mandates removal from the road.
Who gets cited most
Our data does not contain state-level breakdowns for this code, so we cannot identify a geographic concentration. However, all-time citations are distributed across nine separate carriers, each with exactly one citation. These carriers include GEO A HALL INC, TOM HASSEL TRANSPORT INC, LAKELAND CARTAGE INC, W C TRANSPORT INC, ASPHALT & FUEL TRANSPORT LLC, ROBERTO FLORES, SANDERS GOLD EAGLE TRANSPORTATION LLC, SOLIZ HAULING INC, and CLEAN EARTH MATTERS. The single-citation pattern across disparate fleets suggests this violation occurs sporadically rather than as a systemic issue within any particular carrier operation.
How severe is this compared to similar codes
In the Hazardous Materials category, 172.325(a) is far less frequently cited than closely related placarding and loading violations. For example, 177.834A-HMC (general loading/unloading hazmat) has 3,954 citations with a 99.2% OOS rate, and 177.834(a) has 3,839 citations with a 97.9% OOS rate. Even the more specific 177.817(a) (placarding violation) shows 2,274 citations at a 75.1% OOS rate.
At the lower end of severity, 172.602(c)(1) (maintenance/accessibility of Emergency Response information) has 1,464 citations but a 0.0% OOS rate, matching 172.325(a)'s enforcement posture. The rarity of 172.325(a) citations and the complete absence of OOS placements suggest inspectors rarely encounter unmarked elevated temperature materials, or when they do, the issue is resolved quickly without roadside sanctions.
How to avoid it
If you transport elevated temperature materials, these pre-trip and en-route actions will help you stay compliant:
- Verify the "Hot" marking before you leave the shipper. Walk around your entire load and confirm that a visible, legible "Hot" label or sticker is affixed to the cargo or shipping document pocket. Do not assume the shipper applied it; confirm it yourself.
- Check the marking for readability and durability. Ensure the label is not faded, obscured by dirt, or peeling. Heat and weather can degrade adhesive labels; if you see any degradation during a rest stop, report it to the carrier so it can be replaced.
- Know your cargo type. If you are hauling asphalt, bitumen, molten metals, or other thermally conditioned materials, understand that the "Hot" marking is mandatory. Clarify with your dispatcher or shipper if you are unsure whether your load qualifies.
- Document the marking at shipper and receiver. Take a photo or note the presence of the "Hot" marking when you pick up and deliver. This creates a paper trail that protects you if an inspector later asks whether the marking was in place during transport.
- Maintain marking integrity during transport. Avoid overloading, excessive vibration, or storage near moisture that could peel or damage labels. Periodically glance at your load during fuel and rest stops to confirm the marking is still visible.