Investigating potential changes to the IIHS side impact crashworthiness evaluation program

Ninety-seven percent of 2016 model year vehicles evaluated in the Insurance Institute for Highway Safety (IIHS) side impact test received good ratings. Good-rated vehicles have lower side impact fatality rates than other vehicles, but additional crashworthiness improvements may be possible. In a previous analysis of real-world cases, most serious injuries in good-rated vehicles resulted from crashes with impacts centered farther forward than the IIHS configuration and/or crashes that produced greater intrusion at the occupant location. The current study examines whether the occurrence of real-world injury in a different crash configuration can be identified in the laboratory, how injury risk in such a configuration compares to the current IIHS test, and whether current vehicle designs already offer improvements over the vehicles in the real-world cases (median model year was 2007). A NASS-CDS crash of a 2007 Honda Fit struck by a 1999 Toyota Camry was chosen for laboratory replication. The nearside impact location was centered forward of the front axle and the 75-year-old driver occupant sustained fatal thoracic injuries. A WorldSID-50th percentile male ATD with a RibEye deflection measurement system was used to record injury measures, and these were compared to measures from four additional tests. In the first, the case vehicle was struck by the IIHS MDB at the standard test location and speed (50 km/h). In the second, the reconstruction test was repeated using a 2015 Honda Fit as the struck vehicle. The third and fourth tests involved the IIHS MDB impacting the 2015 Fit at the standard location at 50 km/h and 60 km/h, respectively. The reconstruction test of the 2007 Fit produced structural damage comparable to the real-world case. Compared to the standard IIHS test, the torso airbag deployment time was similar, the ATD loading was later due to the longer crash pulse, and there was less intrusion at the occupant position. Despite these differences, the injury measures recorded by the ATD were broadly similar and indicated elevated injury risks consistent with the observed realworld injuries. Compared to the 2007 model, the 2015 Fit produced much lower intrusion and injury measures in the reconstruction and standard IIHS tests. The greatest injury risks in all five tests were recorded when the 2015 Fit was impacted by the IIHS MDB at 60 km/h. The loading and intrusion patterns in the real-world reconstruction differed from the standard IIHS test, but did not translate to large differences in predicted injury risks. Furthermore, tests of the newest generation Fit suggest some of the risk factors observed in the real-world crash have been mitigated by more recent crashworthiness improvements. However, the benefit of these improvements was more than offset by the increased severity of a 60 km/h test. Simply increasing the severity of the current IIHS test may be more effective at producing additional real-world improvements than a test configuration that has a different impact location but does not result in increased intrusion. However, more research would be needed to ensure that a higher severity test does not promote countermeasures with reduced protection in less severe crashes.