393.55D1-B — Coupling device/towing methods defective
FMCSA violation code under Vehicle Maintenance. 24,688 events recorded in roadside inspections. Severity weight: 8.
Violation code 393.55D1-B is a Federal Motor Carrier Safety Regulations citation issued under 49 CFR 393.55. It tracks a specific compliance failure recorded against motor carriers and drivers during FMCSA roadside inspections. The code rolls up into the FMCSA Safety Measurement System (SMS) Vehicle Maintenance BASIC, which feeds the carrier's percentile ranking and prioritization for FMCSA interventions. It applies to interstate motor carriers, drivers, and the commercial motor vehicles they operate; intrastate operators are subject when their state has adopted Part 350 of the FMCSR by reference. It carries a severity weight of 8, 24,688 citations have been recorded against this code in the FMCSA inspection record.
- Code:
- 393.55D1-B
- Code System:
- FMCSR
- BASIC Category:
- Vehicle Maintenance
- OOS Eligible:
- No
- Severity Weight:
- 8
- Total Events:
- 24,688
- Carriers Cited:
- 12,010
Ranks #117 of 3,146 FMCSR codes by citation frequency • OOS rate of 0.0% is below the FMCSR-wide average of 33.2%.
Violation Description
Coupling devices or towing methods on commercial motor vehicle are defective or inadequate.
About This Violation Code
Code 393.55D1-B falls under the Vehicle Maintenance BASIC category in FMCSA's Safety Measurement System (SMS). It carries a severity weight of 8 (scale 1-10, higher = more severe).
When this violation is cited during a roadside inspection, it contributes to the carrier's Vehicle Maintenance BASIC score. Carriers with high BASIC percentiles may be prioritized for FMCSA interventions including warning letters, investigations, or compliance reviews.
Regulatory Reference
Federal Motor Carrier Safety Regulations
This violation references 49 CFR 393.55D1 in the Federal Motor Carrier Safety Regulations.
Top Enforcing States
Where 393.55D1-B is most commonly cited (last 180 days)
Click a state to see roadside inspection activity, top stations, and carrier profiles in that jurisdiction.
Citation Trend (12 months)
Monthly count of 393.55D1-B citations. Red bars mark months with OOS-triggering citations.
Most Active Stations
Inspection stations citing 393.55D1-B most often (last 180 days)
Often Cited Together
Other violations commonly found on the same inspection (last 90 days)
Citation patterns suggest related root causes (e.g., HOS violations paired with logbook errors).
Top Carriers Cited
Ranked by frequency • 12,010 carriers total • Page 1 of 481
Recent Inspections
Latest inspections where 393.55D1-B was cited • 24,688 total events • Page 1 of 988
| Date | Report # | State | Level | OOS |
|---|---|---|---|---|
| 88350047 | MA | Level 2 | No | |
| 88349609 | CA | Level 1 | No | |
| 88349578 | MI | Level 1 | No | |
| 88348909 | CA | Level 2 | No | |
| 88348783 | US | Level 1 | No | |
| 88347205 | US | Level 1 | No | |
| 88347149 | NJ | Level 2 | No | |
| 88347123 | VA | Level 2 | No | |
| 88347079 | NJ | Level 2 | No | |
| 88346970 | CA | Level 1 | No | |
| 88346889 | CA | Level 3 | No | |
| 88346770 | US | Level 1 | No | |
| 88346641 | CT | Level 2 | No | |
| 88349297 | VA | Level 2 | No | |
| 88347053 | US | Level 1 | No | |
| 88346813 | US | Level 1 | No | |
| 88346793 | US | Level 1 | No | |
| 88346723 | US | Level 1 | No | |
| 88344622 | UT | Level 1 | No | |
| 88344586 | MO | Level 1 | No | |
| 88344435 | CA | Level 1 | No | |
| 88343771 | FL | Level 2 | No | |
| 88342846 | MO | Level 1 | No | |
| 88342831 | US | Level 1 | No | |
| 88342807 | US | Level 1 | No |
How to comply with violation code 393.55D1-B
- Locate the regulation in the eCFR. Open https://www.ecfr.gov/current/title-49/section-393.55 on eCFR.gov to read the legal text the citation is written against. The eCFR is the National Archives' continuously updated electronic Code of Federal Regulations and is the canonical reference for any FMCSR section.
- Determine if your operation is subject. Confirm whether your operation is interstate (always subject to the FMCSR) or intrastate (subject when your state has adopted 49 CFR Part 350 by reference; most have). Intrastate operators in non-adopting states may be subject to a state analog instead of the federal rule.
- Identify the documented requirement. Read the requirement carefully: "Coupling devices or towing methods on commercial motor vehicle are defective or inadequate." Map it to the specific equipment, driver document, or operational practice it covers.
- Inspect or maintain to standard. Build a recurring inspection, training, or filing routine that catches this gap before a roadside inspector does. Pre-trip checks, scheduled preventive maintenance, driver-qualification file audits, and supervisor reviews are the standard places this kind of issue is caught early.
- Document compliance to demonstrate it on review. Keep a dated, signed record of each inspection, repair, training session, or filing tied to 393.55D1-B. During an FMCSA compliance review or a customer onboarding audit, the documentation is what proves the program runs — undocumented compliance is indistinguishable from non-compliance to the auditor.
Frequently asked questions about 393.55D1-B
What is FMCSA violation code 393.55D1-B? ▾
Is 393.55D1-B an out-of-service violation? ▾
What's the severity weight of 393.55D1-B? ▾
How many inspections have cited 393.55D1-B? ▾
Which BASIC category is 393.55D1-B in? ▾
What does a carrier do to fix 393.55D1-B? ▾
Where can I find related violation codes? ▾
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About FMCSA violation codes
Every violation found during an FMCSA roadside inspection is recorded under a code drawn from the Federal Motor Carrier Safety Regulations — the codified safety rules motor carriers, drivers, and commercial motor vehicles must comply with in interstate commerce. Codes roll up into one of seven Behavior Analysis and Safety Improvement Categories (BASICs): Unsafe Driving, Hours-of-Service, Driver Fitness, Controlled Substances/Alcohol, Vehicle Maintenance, Hazardous Materials Compliance, and Crash Indicator. Each code carries a published severity weight (1–10) and an Out-of-Service eligibility flag.
Citations counted in the FMCSA Safety Measurement System (SMS) feed a 24-month rolling percentile rank for every motor carrier. Recent citations weigh more heavily than older ones — FMCSA applies a 3× multiplier to events 0–6 months old, 2× for 6–12 months, and 1× for 12–24 months. Carriers above the published intervention threshold for a given BASIC are prioritized for warning letters, focused investigations, and full compliance reviews.
TruckCodex mirrors the FMCSA Motor Carrier Management Information System (MCMIS) and the published violation dictionary on a daily refresh cycle. We do not author or modify violation records — every count, severity weight, and OOS flag on this page reflects what the FMCSA has on file. For real-time confirmation immediately before an enforcement decision, click through to the FMCSA Violations Search link above. Carriers who believe a citation was recorded in error can file a Request for Data Review through the FMCSA DataQs system.
Related Records
Data sources & freshness
TruckCodex aggregates official public-sector datasets. See the Source registry for dataset-level coverage and the Freshness log for last-import timestamps.
Census, SAFER, SMS, Licensing & Insurance (L&I), roadside inspections, crashes, and authority history.
Vehicle recall campaigns, defect investigations, and consumer safety complaints (SCRS).
Cross-border carrier registry and Canadian recall campaigns where applicable.
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