How is a violation’s severity weight determined in the CSA Safety Measurement System (SMS)?

All inspection violations that pertain to a Behavior Analysis and Safety Improvement Category (BASIC) under Compliance, Safety, Accountability (CSA) are assigned violation weights that reflect their association with crash occurrence and crash consequences. The violation weight helps differentiate the levels of crash risk associated with the various violations attributed to each BASIC. Violation weight is assigned on a 1-10 scale, where 1 represents the lowest crash risk and 10 represents the highest crash risk relative to the other violations in the BASIC. Also, an additional weight of 2 is applied to violations that result in out-of-service orders.

Crashes are assigned severity weights according to their impact. Greater weight is attributed to crashes involving injuries, fatalities, and/or the release of hazardous materials than to crashes only resulting in a vehicle tow-away.

Because the weights reflect the relative importance of each violation within each particular BASIC, they cannot be compared meaningfully across the various BASICs. The Safety Measurement System (SMS) severity weights are subject to change.