Evaluation of 2006 South Carolina Crash Data Reported to the MCMIS Crash File

This document is part of a series of reports 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. Earlier studies showed that reporting to the MCMIS Crash file was significantly incomplete in other states. This report examines the sources of underreporting for the state of North Carolina. MCMIS Crash file records were matched to the North Carolina Police Accident Report (PAR) file to determine the nature and extent of reporting. Overall, North Carolina submitted 48.2% of its reportable crash involvements to the MCMIS Crash file in 2003. Reporting rates varied by vehicle type, crash severity, and reporting agency. Reporting rates are 63.3% for fatal crashes, 49.4% for injury cases, and 47.1% for tow/disabled accidents. Two-axle trucks are reported only 15.7% of the time, while tractor semitrailers and truck tractors each have reporting rates over 81%. Buses are only reported 9.9% of the time. Interstate vehicles were reported at a rate of 73.6%, compared with 40.3% for vehicles with in-state license plates. The highway patrol reported 58.2% of cases they covered compared with 35.4% for the local police. Although North Carolina's data collection system is comprehensive, it appears that issues connected with identifying the target vehicle as a commercial motor vehicle (CMV) is preventing all MCMIS-eligible vehicles from being identified. Officers are less likely to recognize smaller vehicles and those operating in-state as CMVs, and thus do not record the CMV variables for these cases. Evidence suggests that failure to fill out the CMV section of the PAR form results in such cases not being submitted to the MCMIS Crash file.