What 172.336C means in plain language
When you're transporting hazardous materials, federal regulations require you to display specific identification numbers on your vehicle in exact locations and formats. Code 172.336C addresses failures to show these ID numbers according to the detailed provisions laid out in a reference table within the broader 172.336 regulation.
These ID numbers—often called "ID numbers" or hazmat identification placards—serve as critical communication tools for emergency responders. They tell first responders what substance is on your truck and help them understand the hazards and response procedures needed if something goes wrong. If an inspector finds that your ID numbers are missing, illegible, displayed in the wrong location, or don't match your cargo, you can be cited under this code.
This violation sits squarely in the hazardous materials compliance category and reflects the DOT's expectation that every hazmat shipment is tracked and identified with precision from load to delivery.
What our enforcement data actually shows
Across our 13 million+ inspection records, code 172.336C is a relatively uncommon violation—ranked #2110 of 3,036 FMCSR codes by citation volume. All-time, we have recorded 13 citations for this offense. Over the last 12 months, we've seen 4 citations, and in the most recent 90-day window, 2 citations appeared in our database.
The out-of-service rate for 172.336C stands at 53.8% (7 out-of-service placements out of 13 total citations). This is notably higher than the all-FMCSR average OOS rate of 31.4%, suggesting that when this violation is found, inspectors view it as serious enough to remove the vehicle from service more than half the time. That said, the code is not classified as OOS-eligible under the FMCSR, meaning the decision to place a vehicle out of service is made on a case-by-case basis rather than as a blanket rule.
Monthly data from the last 12 months shows sporadic enforcement: citations appeared in July 2025, October 2025, February 2026, and March 2026, with one citation and one out-of-service placement in each month.
Who gets cited most
Our enforcement data shows that Texas accounts for 2 citations in the last 180 days, both of which resulted in out-of-service placements (100.0% OOS rate). The limited geographic spread in recent months reflects how rare this citation is across the country.
Looking at all-time carrier data, ECO TRANSPORTES INTERNACIONALES SA DE CV (USDOT 558117) shows 4 citations—the highest count in our database. This does not imply a pattern of negligence; rather, it reflects that this carrier has moved higher volumes of hazmat shipments or operated in inspection-heavy jurisdictions. Other carriers in our records with this citation include GREENWOOD MOTOR LINES INC, UNITED PETROLEUM TRANSPORTS INC, and several smaller operations, each with single citations.
Vehicle makes most frequently cited include utility vehicles (UTIL, 4 citations), navigation/specialized haulers (NAVI, 3 citations), and Kenworth units (KW, 3 citations). This mix aligns with the diversity of hazmat carriers operating across the country.
How severe is this compared to similar codes
Within the hazardous materials category, 172.336C is relatively mild in enforcement frequency compared to its peer codes. For context:
- 177.834A-HMC (General loading/unloading of hazmat) has logged 3,954 citations all-time with a 99.2% out-of-service rate—far more aggressive enforcement and much higher consequence severity.
- 177.817(a) (Placarding violation) shows 2,274 citations with a 75.1% OOS rate, also substantially higher in volume and severity than 172.336C.
- 172.516(c)(6) (Placard damaged, deteriorated, or obscured) has 1,796 citations but only a 1.6% OOS rate, indicating that missing or illegible placards are treated differently depending on the exact nature of the defect.
Your 172.336C citation is infrequent but, when issued, carries above-average consequences relative to the broader FMCSR population.
How to avoid it
Based on patterns in our inspection data, here are concrete steps to ensure compliance:
- Inspect ID numbers before every trip. Check that all required identification numbers are visible, legible, and affixed securely to the exterior of your vehicle. Do not rely on fading or partially obscured placards from previous loads.
- Verify placement against the reference table. Familiarize yourself with where ID numbers must be displayed (typically on all four sides of the vehicle or on each side and front/rear as specified). Use a checklist or photo guide during pre-trip inspection.
- Match cargo to displayed numbers. Before departure, confirm that the ID numbers on your vehicle match the hazmat description on your shipping papers. Mismatches are a common trigger for citations.
- Check condition and adhesion. Our data shows that placard integrity issues (codes 172.516C1, 172.519) often appear alongside ID number violations. Ensure placards are not peeling, faded, or at risk of detachment during transport.
- Stay alert during operation. Data indicates that operator fatigue (code 392.2W) co-occurs with this violation in recent inspections. Maintain alertness during pre-trip and en-route, and perform a final spot-check at your destination before unloading.
- Document your compliance. Photograph or record your pre-trip inspection, particularly for hazmat loads. This creates a defense if an inspector's citation is disputed.
The low citation count for this code means most drivers are already compliant. Staying compliant is primarily a matter of thoroughness: treat every hazmat shipment as a regulated event, verify your placards before you leave the yard, and do not move a vehicle if ID numbers are illegible or missing.