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A New Model of Crash Severities Reportable to the MCMIS Crash File

The Motor Carrier Management Information System (MCMIS) Crash file has been developed by the Federal Motor Carrier Safety Administration (FMCSA) to serve as a census file of trucks and buses involved in traffic crashes meeting a specific crash severity threshold. Each state is responsible for identifying cases that meet the MCMIS Crash file criteria and reporting the required data through the SafetyNet system. The present report is an addition to three previous reports describing models to predict the number of crash involvements a state should be reporting. The model has been updated and changed over time as more data becomes available from additional states. In each state, the number of fatal involvements is well-known, so all states will start with a known quantity, the number of fatal truck and bus crash involvements. The new model also incorporates a rural/urban (RU) factor that accounts for the relative proportion of rural to urban truck travel in a state. In the new model, data from 16 states that provide all the information necessary to identify MCMIS-reportable cases were used. A log-linear model is fit to MCMIS data for the states that have information recorded for both fatal and nonfatal crashes. The model is then used to predict the number of nonfatal crashes for a new state in which the number of fatal crashes and the RU factor are known. Ninety percent prediction intervals provide a range of nonfatal crash values to be used for guidance. The new model provides more accurate prediction than previous models and is expected to be updated as data from additional states become available.

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