About the Algorithm

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About the Algorithm

Three distinct categories of shipper performance are evaluated:

•	Enforcements

•	Inspections

•

Incidents

Those shippers with the calculated highest risk of future incident are assigned the highest Prioritization Score (PS), and those with the lowest risk are assigned the lowest PS. The PS is calculated as the sum of each individual score, as follows:

Prioritization Score = ES+INS+ITS

Where:

ES = Enforcement Score

INS = Inspection Score

ITS = Incident Score

Each category is further broken down into four weighted variables:

•	Severity: The weights are directly proportional to the severity, and a greater severity is assigned a greater weight.

•	Recency: A greater value is assigned for a more recent violation, but decreases over time.

•	Material involved: Material is calculated by a chart assigning weights to each type of HM by class and division.

•	Frequency: Multiple violations account for the frequency of violations.

The product of all four variables becomes the individual Enforcement, Inspection, or Incident1 Score.

For detailed information on data and score variables used in the algorithm, please refer to the Development of Hazardous Materials (HM) Shipper Prioritization Program Technical Brief, February 2009, (Contract No. TMC75-07-H-00008), Washington, DC: Federal Motor Carrier Safety Administration.