What 397.7A3-HMDP means in plain language
This citation means you parked a commercial motor vehicle carrying hazardous materials in a location that was not authorized. Hazmat parking rules exist because hazardous cargo poses a public safety risk if left unattended or in the wrong place. Federal regulations designate specific, safe locations where you can leave a vehicle loaded with hazmat — and parking anywhere else violates 397.7A3-HMDP.
Authorized hazmat parking is typically marked clearly at truck stops, warehouses, and distribution centers. It may be fenced, monitored, or otherwise secured. If you parked at a location that wasn't designated for hazmat storage or left your rig in a public area, a roadside inspector can cite you. The violation applies regardless of whether the hazmat itself was properly labeled, placarded, or loaded — the issue is purely about where the truck was positioned.
What our enforcement data actually shows
Across 13 million inspections in our database, 397.7A3-HMDP has been cited only 1 time all-time, with 1 citation in the last 12 months and 0 in the last 90 days. This code ranks #2796 of 3,036 FMCSR codes by citation volume, making it one of the least-cited violations in the hazmat category.
The out-of-service rate for 397.7A3-HMDP is 0.0% — meaning the single citation on record did not result in an out-of-service order. This is significantly lower than the all-FMCSR average OOS rate of 31.4%, and it reflects the rarity of this violation in actual roadside enforcement. Our data shows this code is infrequently encountered, but when it does occur, inspectors treat it as a citation-level offense rather than an immediate safety removal.
Who gets cited most
Our inspection records show that the single citation for 397.7A3-HMDP involved a vehicle operated by Fuel South Express LLC (USDOT 362702). The citation was recorded in August 2025. With only one citation in our 13 million-record database, there is no meaningful geographic or fleet-level pattern to report. This violation is so rare that no state dominates the enforcement landscape, and no carrier shows a pattern of repeated citations for unauthorized hazmat parking.
How severe is this compared to similar codes
Hazmat parking violations sit in a different enforcement tier than other hazmat violations. Compare 397.7A3-HMDP to related codes in the Hazardous Materials category:
- 177.834A-HMC (General loading/unloading hazmat) has 3,954 citations with a 99.2% OOS rate — far more common and almost always leads to immediate out-of-service.
- 177.817(a) (Placarding violation) has 2,274 citations with a 75.1% OOS rate — more than 2,000 times more frequent than parking violations.
- 172.602(c)(1) (Maintenance/accessibility of Emergency Response information) has 1,464 citations with a 0.0% OOS rate — similar to parking violations in that it does not trigger out-of-service orders.
The data indicates that parking violations are treated as administrative or procedural violations, not as immediate safety threats requiring vehicle removal. Loading, unloading, and placarding violations, by contrast, are treated as direct safety hazards and result in out-of-service orders in the vast majority of cases.
How to avoid it
Because this violation is exceedingly rare, your best defense is awareness of hazmat parking rules before you arrive at a facility.
- Identify authorized hazmat parking before you arrive. Use your dispatch paperwork, call ahead to the receiving facility, or consult the truck stop's hazmat parking map. Ask explicitly where hazmat vehicles are permitted to park. Most major stops have designated hazmat zones — use only those.
- Never park in public areas or unauthorized truck parking. If you cannot find a marked hazmat zone, do not leave your vehicle unattended. Call dispatch for guidance or request a facility representative to escort you to the correct location.
- Verify signage at the location. Before unhooking or settling in, confirm that the parking spot is labeled for hazmat vehicles. If it is not clearly marked, move your vehicle or seek clarification from facility staff.
- Document the parking location. Note the facility name, date, time, and specific lot or zone where you parked hazmat cargo. This creates a record if a question arises about authorization.
- Communicate with dispatch if guidance is unclear. If a facility's hazmat parking instructions are vague or if you arrive to find the usual hazmat zone unavailable, contact your safety or operations team immediately rather than making a judgment call on your own.