The Basic Rule: 24 Months
Most roadside inspection violations stay on your FMCSA Safety Measurement System (SMS) record for 24 months from the date of the inspection. That is the standard lookback window FMCSA uses when calculating your BASIC percentiles. However, not all violations carry equal weight for the entire period. FMCSA's SMS algorithm applies a time weight that reduces the impact of older violations:
- Violations from the most recent 6 months carry full weight
- Violations from 7 to 12 months ago carry reduced weight
- Violations older than 12 months carry the lowest weight
This means a string of violations from 18 months ago is still hurting your percentile — just less than when it first posted.
Crashes: 24 Months With a Different Calculation
Crashes recorded in MCMIS also have a 24-month lookback period. However, how a crash affects your Crash Indicator BASIC depends on whether it was deemed preventable. Successfully challenging a crash through FMCSA's Crash Preventability Determination Program can change how that crash is weighted in your SMS scores.
Compliance Review Data
Data from compliance reviews has a longer life. Findings from a compliance review can remain in MCMIS and affect your profile for up to 5 years, depending on the nature of the finding and FMCSA's data retention policies.
Investigation Results
Investigation results, including warning letters and notices of claim, can remain on your carrier profile and be visible to enforcement personnel even after the standard SMS lookback window expires. These records do not fall off automatically in all contexts.
What This Means Practically
If your SMS percentiles are elevated right now, there are really only two ways to improve them: challenge inaccurate violations through DataQ, or run clean inspections going forward and let time work in your favor. Ideally you do both.
The time-weighting system means your most recent 6 months of inspection history have the biggest impact on where you stand today. A focused effort on compliance right now produces measurable results relatively quickly.