Vehicle Maintenance violations: severity weights and frequent codes in a saved snapshot

The severity weight belongs to this BASIC

FMCSA's SMS Methodology assigns severity weights from 1 to 10 for relative crash risk within a BASIC. A weight in Vehicle Maintenance should not be compared with the same weight in another BASIC (p. 2-4).

Vehicle Maintenance uses applicable violations from Level 1, 2, 5, and 6 vehicle inspections in the past 24 months. Multiple occurrences of the same violation cite count once per inspection (p. 3-14).

The code pages below show every distinct severity weight observed in the public violations file. A code with two observed weights is not assigned their sum or average; the calculation starts with the weight recorded for the individual violation.

The out-of-service addition

The Vehicle Maintenance section states: "OOS violations receive an additional severity weight of 2." (p. 3-14). Add that to the violation's severity when the recorded violation has the OOS condition. The out-of-service guide covers the rule and its exceptions.

The 30-point cap comes before the time weight

Sum the Vehicle Maintenance severity weights, including OOS additions, for one inspection and cap that sum at 30. Violations in other BASICs do not enter this cap (p. 3-15).

The methodology states: "This cap of 30 is applied before the severity weights are multiplied by the time weight." (p. 3-15). Synthetic arithmetic example: if an inspection's sum is 34, it enters the time-weighting step as 30. Removing a weight of 2 would leave 32, still capped at 30, so that inspection's contribution would be unchanged.

The inspection's age and the measure

The time weight is ×3 for the past six months, ×2 for over six months through 12 months, and ×1 for over 12 months within the 24-month window (p. 3-15). An inspection capped at 30 therefore contributes 90, 60, or 30 to the numerator in those bands.

The Vehicle Maintenance denominator is the total time weight of relevant vehicle inspections, including inspections with no violation in the BASIC (pp. 3-14–3-15). Those numerator contributions are not the measure itself. The SMS measure guide explains the division and the effect of removing one violation.

Read these age bands relative to the snapshot date. They describe that snapshot's calculation, not a promised date for a record to disappear.

A lower time weight reduces an inspection's weighted numerator contribution; it need not lower the measure. For inspection-normalized BASICs, time weight also applies to relevant inspections in the denominator, including inspections with no violation in that BASIC. The result depends on all relevant inspections in the same snapshot; their aging, arrival, or departure can change the denominator too. Exposure-normalized BASICs use a different denominator.

Synthetic arithmetic example for an inspection-normalized BASIC: with one relevant inspection, severity 6 and time weight ×3, the ratio is 18/3 = 6. When its time weight becomes ×2, the ratio is 12/2 = 6. This illustrates normalization only; it does not establish enough data for a published position.

The codes that appear most in the public data

The five codes below have the highest Vehicle Maintenance row counts in this site's saved aggregates for the public SMS violations snapshot dated 2026-07-31. Counts are violation rows, not unique carriers or inspections. The weights are observed severity values, before OOS additions. This editorial review checked the saved aggregates and their display; it did not independently recount the original FMCSA file. The download-directory link identifies the publisher, not an archived copy of that snapshot.

• 393.9 — Inoperable Required Lamp: 177,440 appearances; observed severity weights: 1, 2. Snapshot 2026-07-31; counts are violation rows.
• 393.47E — Brake Out of Adjustment - Roto Clamp (Short & Long) DD-3 or Bolt: 168,888 appearances; observed severity weights: 1, 4. Snapshot 2026-07-31; counts are violation rows.
• 393.75A3TAOL — Tires - All others leaking or inflation less than 50% of the maximum inflation pressure on tire not equipped with ATIS: 163,539 appearances; observed severity weights: 1, 8. Snapshot 2026-07-31; counts are violation rows.
• 396.17CPI — Operating a CMV without documentation of a periodic inspection: 148,578 appearances; observed severity weights: 1, 4. Snapshot 2026-07-31; counts are violation rows.
• 393.9ALIL — Lighting - Identification lamp(s) inoperative: 108,066 appearances; observed severity weights: 2. Snapshot 2026-07-31; counts are violation rows.