Violation code

392.4(a)

Driver uses or is in possession of drugs

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

392.4(a) is a Drugs violation under 49 CFR §392.4(a). It falls in the Controlled Substances/Alcohol BASIC with a severity weight of 10/10. Nationally it was cited 665 times in the last five years, with an OOS rate of 93.5%.

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National roadside inspection stats

as of 9/20/2026

Inspections

588

that found this code

Violations

665

total written

OOS rate

93.5%

622 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 §: 392.4(a)
Severity weight: 10
Used in SMS: Yes
Status: Active
Updated: 9/20/2026

Last updated September 2026

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Notes

DSMS: Y

What 392.4(a) means — and how to avoid it

In plain English

In plain terms, 392.4(a) is cited for driver uses or is in possession of drugs. It falls under the FMCSA rules on safe driving of commercial vehicles.

What the inspector checks

•Signs of impairment or possession
•Testing-program compliance where applicable

How to prevent it

✓Zero tolerance on duty; know your carrier’s testing policy
✓Never operate within the prohibited window after alcohol

How it affects your CSA

up to 30 pts (fresh)

Severity 10/10. A fresh citation counts at the 3× time weight — up to 30 points toward the Controlled Substances/Alcohol BASIC — then tapers to 2× after 6 months and 1× after a year, dropping off the score at 24 months.

General guidance from the violation’s FMCSA classification — not legal advice, and not a substitute for the inspector’s findings or 49 CFR.

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Challenging 392.4(a) 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 392.4(a) →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 →

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Frequently asked questions about 392.4(a)

What does violation 392.4(a) mean?

392.4(a) is the FMCSA roadside-inspection violation code for "Driver uses or is in possession of drugs", part of the Drugs group, cited under 49 CFR §392.4(a).

What BASIC does 392.4(a) affect?

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

What is the CSA severity weight of 392.4(a)?

392.4(a) 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 392.4(a) an out-of-service (OOS) violation?

No. 392.4(a) 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 392.4(a) add to a carrier's score?

The point contribution of 392.4(a) 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.

How can a driver prevent 392.4(a)?

Zero tolerance on duty; know your carrier’s testing policy; Never operate within the prohibited window after alcohol.

Can 392.4(a) be challenged through DataQs?

Yes. If you believe 392.4(a) 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 392.4(a)Controlled Substances/Alcohol BASIC Carrier CSA lookup CSA glossary

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