Violation code

172.334

Prohibited ID number marking

Hazardous Materials Compliance5Non-OOS· SMS Appendix A v3.20

172.334 is a Markings - HM violation under 49 CFR §172.334. It falls in the Hazardous Materials Compliance BASIC with a severity weight of 5/10. Nationally it was cited 472 times in the last five years, with an OOS rate of 42.2%.

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National roadside inspection stats

as of 6/20/2026

Inspections

466

that found this code

Violations

472

total written

OOS rate

42.2%

199 OOS

Source: FMCSA roadside inspection data (last 5 years). The OOS rate is the share of these violations that led the officer to mark the driver or vehicle out of service.

Violation group: Markings - HM
Regulation §: 172.334
Severity weight: 5
Used in SMS: Yes
Status: Active
Updated: 6/20/2026

Last updated June 2026

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Notes

DSMS: N

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Challenging 172.334 through FMCSA DataQs

If this violation was written incorrectly, here are the angles trucking-safety managers use to contest it. Playbook: Hazardous Materials.

Common ways to challenge this code

Shipment was not placardable
The materials transported did not exceed the threshold quantities requiring placards under 49 CFR Part 172 Subpart F.
Evidence that wins
- ✓Shipping papers showing UN number, hazard class, and quantity
- ✓Manufacturer's product specification sheet
Administrative HazMat code (not in SMS)
This administrative code is on the inspection report but does not contribute to CSA BASIC scoring per FMCSA SMS Methodology Appendix A.
Evidence that wins
- ✓FMCSA SMS Methodology Appendix A reference

Common pitfalls — avoid these

⚠Administrative HazMat codes still appear on the PSP record even when not scored in SMS

⚡ Draft a challenge for 172.334 →Read the DataQs guide first

More codes in Hazardous Materials Compliance

Same BASIC category — ranked by national citation volume

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Other Markings - HM codes

Codes under the same FMCSA violation group

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Frequently asked questions about 172.334

What does violation 172.334 mean?

172.334 is the FMCSA roadside-inspection violation code for "Prohibited ID number marking", part of the Markings - HM group, cited under 49 CFR §172.334.

What BASIC does 172.334 affect?

172.334 falls under the Hazardous Materials Compliance BASIC in the FMCSA Safety Measurement System (SMS).

What is the CSA severity weight of 172.334?

172.334 carries a severity weight of 5 out of 10. Higher weights indicate violations more closely tied to crash risk, and they count more toward a carrier's Hazardous Materials Compliance score.

Is 172.334 an out-of-service (OOS) violation?

No. 172.334 is not an out-of-service violation, so on its own it does not trigger an out-of-service order at the roadside.

How many CSA points does 172.334 add to a carrier's score?

The point contribution of 172.334 depends on its severity weight (5/10) multiplied by a time weight of 3, 2, or 1 based on how recent the inspection is. You can calculate the exact contribution with the CSA points calculator.

Can 172.334 be challenged through DataQs?

Yes. If you believe 172.334 was recorded in error, you can file a Request for Data Review (RDR) through the FMCSA DataQs system with supporting evidence. A successful challenge can remove or correct the violation on your record.

Keep going

CSA points calculator How to challenge a violation Draft a DataQs letter for 172.334 Hazardous Materials Compliance BASIC Carrier CSA lookup CSA glossary