Violation code

173.66

Failure to comply with requirements for Explosive Bulk Trucks

Not in SMSOOS· FMCSA A&I All Violations

173.66 is a HazMat violation under 49 CFR §173.66. It is an out-of-service violation; it is not scored in the SMS. Nationally it was cited 2 times in the last five years, with an OOS rate of 50.0%.

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National roadside inspection stats

as of 6/20/2026

Inspections

that found this code

Violations

total written

OOS rate

50.0%

1 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.

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Not used in SMS BASIC scoring

Recorded on your inspection report and visible on the PSP, but contributes 0 points to CSA BASIC scores — even if cited Out-of-Service.

Violation group: HazMat
Regulation §: 173.66
Severity weight: N/A
Used in SMS: No
Status: Active
Updated: 6/20/2026

Last updated June 2026

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Challenging 173.66 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 173.66 →Read the DataQs guide first

Other HazMat codes

Codes under the same FMCSA violation group

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Frequently asked questions about 173.66

What does violation 173.66 mean?

173.66 is the FMCSA roadside-inspection violation code for "Failure to comply with requirements for Explosive Bulk Trucks", part of the HazMat group, cited under 49 CFR §173.66.

What BASIC does 173.66 affect?

173.66 is not scored in any CSA BASIC. It is recorded on the inspection report and appears on the PSP, but it contributes 0 points to a carrier's SMS BASIC percentiles.

Is 173.66 an out-of-service (OOS) violation?

Yes. 173.66 is an out-of-service violation, meaning the driver or vehicle can be placed out of service at the roadside until the issue is corrected. OOS violations also add an extra severity point in SMS scoring.

How many CSA points does 173.66 add?

173.66 adds 0 CSA points because it is not used in SMS scoring, even when written out of service.

Can 173.66 be challenged through DataQs?

Yes. If you believe 173.66 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.

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CSA points calculator How to challenge a violation Draft a DataQs letter for 173.66 Carrier CSA lookup CSA glossary