Evaluation of 2005 South Dakota crash data reported to the MCMIS Crash File

Abstract

This report is part of a series evaluating the data reported to the Motor Carrier Management Information System (MCMIS) Crash File undertaken by the Center for National Truck and Bus Statistics at the University of Michigan Transportation Research Institute. The earlier studies showed that reporting to the MCMIS Crash File was incomplete. This report examines the factors that are associated with reporting rates for the state of South Dakota. MCMIS Crash File records were matched to the South Dakota Crash file to determine the nature and extent of underreporting. The South Dakota crash file appears to supply all the information needed to identify cases that qualify for reporting to the MCMIS Crash file. Overall, it appears that South Dakota is reporting 66.4 percent of involvements that should be reported to the MCMIS Crash file. Reporting rates were related to crash severity, with fatal involvements more likely to be reported than less severe crashes, but this difference was not statistically significant because of the small number of cases. Reporting rates also varied by the type of vehicle and the type of investigation agency (highway patrol, county sheriff, or city police). Missing data rates are low for most variables, although were 20.1 percent for driver license class and 67.4 percent for road access. Consistency between data as recorded in the South Dakota file and as reported to the MCMIS Crash file was excellent.