Violation code

392.4A-UI

Driver on duty and under the influence of, or using a narcotic drug / amphetamine, which renders the driver incapable of safe operation.

Controlled Substances/Alcohol10Non-OOS· SMS Appendix A v3.20

392.4A-UI is a Drugs violation under 49 CFR §392.4A-UI. It falls in the Controlled Substances/Alcohol BASIC with a severity weight of 10/10. Nationally it was cited 1,975 times in the last five years, with an OOS rate of 98.6%.

📊

National roadside inspection stats

as of 6/20/2026

Inspections

1,964

that found this code

Violations

1,975

total written

OOS rate

98.6%

1,947 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: Drugs
Regulation §: 392.4A-UI
Severity weight: 10
Used in SMS: Yes
Status: Active
Updated: 6/20/2026

Last updated June 2026

⚡

Think this violation was written incorrectly?

Generate a polished DataQs challenge letter for 392.4A-UI in about 5 seconds. AI quotes the CFR, predicts your grant chance.

⚡ Draft a challenge →

Notes

DSMS: Y | Comment: Added in 3.0.8 | Footnote: This violation was applied retroactively in the SMS with the July 28, 2017 run.

📚

Challenging 392.4A-UI through FMCSA DataQs

If this violation was written incorrectly, here are the angles trucking-safety managers use to contest it. Playbook: Controlled Substances / Alcohol.

Common ways to challenge this code

Drug & Alcohol Clearinghouse record was misreported
The reported positive test, refusal, or violation was misattributed or already resolved through the return-to-duty process.
Evidence that wins
- ✓Clearinghouse query result for the relevant date
- ✓MRO (Medical Review Officer) report
- ✓Substance Abuse Professional follow-up plan completion

Common pitfalls — avoid these

⚠Drug & Alcohol challenges have high bar — engage the MRO directly before filing

⚡ Draft a challenge for 392.4A-UI →Read the DataQs guide first

More codes in Controlled Substances/Alcohol

Same BASIC category — ranked by national citation volume

View all Controlled Substances/Alcohol codes →

Other Drugs codes

Codes under the same FMCSA violation group

392.4(a)
10
Driver uses or is in possession of drugs

❓

Frequently asked questions about 392.4A-UI

What does violation 392.4A-UI mean?

392.4A-UI is the FMCSA roadside-inspection violation code for "Driver on duty and under the influence of, or using a narcotic drug / amphetamine, which renders the driver incapable of safe operation.", part of the Drugs group, cited under 49 CFR §392.4A-UI.

What BASIC does 392.4A-UI affect?

392.4A-UI falls under the Controlled Substances/Alcohol BASIC in the FMCSA Safety Measurement System (SMS).

What is the CSA severity weight of 392.4A-UI?

392.4A-UI carries a severity weight of 10 out of 10. Higher weights indicate violations more closely tied to crash risk, and they count more toward a carrier's Controlled Substances/Alcohol score.

Is 392.4A-UI an out-of-service (OOS) violation?

No. 392.4A-UI 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 392.4A-UI add to a carrier's score?

The point contribution of 392.4A-UI depends on its severity weight (10/10) 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 392.4A-UI be challenged through DataQs?

Yes. If you believe 392.4A-UI 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 392.4A-UI Controlled Substances/Alcohol BASIC Carrier CSA lookup CSA glossary