Long-term data systems typically need to evolve to keep pace with changing elements in the data environment. The crash data systems developed and maintained by the National Highway Traffic Safety Administration (NHTSA) are not immune to such demands. Changes in the system may be driven by known fleet changes such as the need to expand air bag definitions when additional side and knee air bags were introduced into the fleet several years ago. Changes in the data capture may also arise from issues discovered during research. Prior to the 2008 data year NHTSA crash data systems lacked coding that would identify possible compatibility issues related to side impact configurations.

Beginning in 2008, NHTSA adopted new investigation protocols and data elements to improve the documentation of the aspects of a crash that aid in identifying compatibility issues and bear on the resolution of injury causation scenarios that occur in multivehicle crashes involving the interaction of the frontal-plane of one collision partner with the sideplane of the passenger compartment of the other. The new variables include damage measurements that are designed to enhance the research with respect to door intrusions, by documenting external damage to structures indicating the extent of override/underride in crashes where vehicle compatibility maybe an issue. This paper will review the case data that has been amassed in the National Automotive Sampling System Crashworthiness Data System (NASS-CDS) and the Crash Investigation Research and Engineering Network (CIREN) programs for side impact cases where the new techniques and data have been captured. Utilizing the data sets from NASS 2008 in conjunction with CIREN data (2008-10) 524 cases were extracted that indicated capture of the new variables.

This paper will explore the development of a correlation between the new side impact variables collected in NASS-CDS and CIREN and crash severity. The new side impact variables are expected to perform as desired by indicating crash severity and potential for injury causation. The new variables cover a wide array of issues related to side impact crashes. Issues related to compatibility between struck and striking vehicles can be better assessed. The role of door intrusion relevant to pillar and rocker involvement can be pursued as well as using the variables as another metric for crash severity. Do the new side impact variables captured in the NASSCDS and CIREN aid in the identification of compatibility issues and severity of side impact crashes?

This study was limited to the first year of NASS data and two years of CIREN data collection on the new variables. This paper describes new variables available to research crashes involving the frontal plane of one vehicle and the side plane of the struck vehicle.