The National Highway Traffic Safety Administration's (NHTSA) National Accident Sampling System Crashworthiness Data System (NASS/CDS) collects detailed information on a sample of all police-reported motor vehicle crashes in the United States that involved passenger vehicles towed from the scene due to damage.[1]
This system's occupant injury definitions and severity levels, which are based on the Association for the Advancement of Automotive Medicine's (AAAM) Abbreviated Injury Scale (AIS), are periodically updated. The last major revision, in 1993, changed the injury identifier of all injuries, added injuries, deleted injuries and changed the body region and severity of a substantial number of injuries.[1] These changes confound the direct combining or trending of pre-1993 and 1993 and later NASS data.
This paper reports on the results of using a conversion method to equate pre-NASS-93 and NASS-93 and later injury descriptors and severities. The conversion maps each listed injury description and aspect in the NASS-93 coding manual to the injury descriptions and aspects fisted in the NASS-88 coding manual.
This “full” conversion allows analyses of severity of injuries, frequency of injuries, and comparisons of injuries on an injury by injury basis as well as by category, body region, aspect or lesion by adjusting the NASS-93 and later data to be consistent with pre-NASS-93 data.
The paper discusses the conversion results and illustrates how the conversion can assist organizations that are analyzing data or creating standards based on multi-year NASS data.