Violation code

393.9ALRLIWR

Lighting - Tail lamp - Both lamps on rearmost vehicle inoperative when required to be on

Not in SMSOOS· FMCSA A&I All Violations

393.9ALRLIWR is a Vehicle violation under 49 CFR §393.9ALRLIWR. It is an out-of-service violation; it is not scored in the SMS. Nationally it was cited 358 times in the last five years, with an OOS rate of 98.9%.

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National roadside inspection stats

as of 6/20/2026

Inspections

356

that found this code

Violations

358

total written

OOS rate

98.9%

354 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: Vehicle
Regulation §: 393.9ALRLIWR
Severity weight: N/A
Used in SMS: No
Status: Active
Updated: 6/20/2026

Last updated June 2026

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Challenging 393.9ALRLIWR through FMCSA DataQs

If this violation was written incorrectly, here are the angles trucking-safety managers use to contest it. Playbook: Codes not used in SMS scoring.

Relevant 49 CFR49 CFR § 393.9

Lamps operable, prohibition of obstructions

“All lamps required by this subpart shall be capable of being operated at all times. This section shall not be construed to prohibit motor vehicles being operated with lamps that are momentarily inoperative due to vibration, temperature, or similar transient causes.”

Common ways to challenge this code

Not used in SMS — should not affect BASIC
This code is on the inspection report but is excluded from SMS BASIC scoring per Appendix A. Use DataQs to correct the underlying data quality issue if the code was written in error, but understand it does not affect the CSA percentile.
Evidence that wins
- ✓FMCSA SMS Methodology Appendix A reference
- ✓Underlying inspection report

Common pitfalls — avoid these

⚠These codes still appear on PSP — challenge the data if the cite was wrong

⚡ Draft a challenge for 393.9ALRLIWR →Read the DataQs guide first

Other Vehicle codes

Codes under the same FMCSA violation group

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Frequently asked questions about 393.9ALRLIWR

What does violation 393.9ALRLIWR mean?

393.9ALRLIWR is the FMCSA roadside-inspection violation code for "Lighting - Tail lamp - Both lamps on rearmost vehicle inoperative when required to be on", part of the Vehicle group, cited under 49 CFR §393.9ALRLIWR.

What BASIC does 393.9ALRLIWR affect?

393.9ALRLIWR 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 393.9ALRLIWR an out-of-service (OOS) violation?

Yes. 393.9ALRLIWR 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 393.9ALRLIWR add?

393.9ALRLIWR adds 0 CSA points because it is not used in SMS scoring, even when written out of service.

Can 393.9ALRLIWR be challenged through DataQs?

Yes. If you believe 393.9ALRLIWR 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 393.9ALRLIWR Carrier CSA lookup CSA glossary