The Benefits Of Collecting More Descriptive Information On Serious Crashes

fmcsa.dot.gov, Aug 12, 2005

This section describes how records in the Serious HM Crash Database were analyzed to assess the benefits of collecting more descriptive information on serious crashes. It is based on a comparison of the information in the database to what was initially available in MCMIS and HMIS.

The screening process employed to select the 214 Serious HM Crash Database records adds some analysis constraints. For example, 1,200 MCMIS crashes were screened to identify the 214 accidents. All crashes in which a fatality occurred were selected. All rollovers were also selected. Analyses results for these classes of accidents are valid but should not be generalized to the whole population of HM crashes. Clearly, if all HM rollovers and fatalities have been selected, then analyses results that look for the relationship between these two factors would be valid. However, it is unlikely that an analysis that analyzed the relationship between non-rollover accidents and fatalities would be valid because the selection process has ignored many non-rollover accidents. The selection of rollover and fatal accidents using MCMIS is incomplete because not all rollover accidents are listed in the MCMIS data. One of the recommendations for Phase 2 is to use statistical sampling methods to select a significant fraction of the crashes for which additional information is to be collected. By using such a selection process, it will be possible to statistically validate dependencies among many crash causes and effects.