provides a detailed record of approximately
5,000 crashes investigated each year (NCSA, 2005). To be included in
NASS/CDS,at least one of the vehicles in the crash had to have been to wed from the scene. The NASS/CDS database includes only crashes involving
cars, light trucks, vans, and sport utility vehicles. Heavy vehicles and
motorcycles are not included as subject vehicles in the NASS/CDS
database. Cases are selected for NASS/CDS investigation using a complex
sampling strategy that over samples certain types of crashes including fatal
crashes, crashes involving hospitalized occupants, and crashes involving
late model year vehicles among other factors (NCSA, 2005). To permit
nationally representative estimates to be computed, NASS/CDS provides
weighting factors that account for this sampling scheme. These weights
were applied in the analysis that follows. All statistical analyses were
performed using the SAS V9.1.3 software package.