The association between data collected in IIHS side crash tests and real-world driver death risk.

OBJECTIVE: The Insurance Institute for Highway Safety (IIHS) side crash test has led to crashworthiness improvements, and both overall and component ratings have been shown to be associated with real-world death risk. The objective of the current study was to investigate how crash test measurements, on which component ratings are based, are associated with real-world death risk. METHODS: Driver deaths and police-reported crash involvements were extracted from national crash databases for left-impact crashes of passenger vehicles with standard-feature, head-protecting side airbags for calendar years 2000-2016. Risk of driver death in left-impact crashes was estimated as the number of driver deaths divided by the number of driver police-reported crash involvements. Logistic regression was used to estimate the association between crash test measurements and death risk, controlling for driver and vehicle information. RESULTS: All crash test measurements investigated were associated with driver death risk. For instance, a 10 cm reduction in B-pillar intrusion, a measure of post-crash occupant survival space, was associated with 30% lower driver death risk. For most measures, at least 75% of study vehicles were within the good rating boundary for that measure, and still these measures were associated with driver death risk. Fewer than half of study vehicles earned a good rating for B-pillar intrusion. CONCLUSION: Because performance in measures collected in the IIHS side crash test are strongly associated with real-world driver death risk, one of the ways the crash test program could continue to encourage crashworthiness improvements is by requiring stronger performance on these measures.

Developing an aluminum honeycomb barrier to represent a striking SUV in a side impact crash test.

OBJECTIVE: The Insurance Institute for Highway Safety (IIHS) introduced its side impact ratings test in 2003. Despite manufacturers' improvements to airbags and vehicle structures, 45% of 2018 side crash fatalities on U.S. roadways were in good-rated vehicles, suggesting that more crashworthiness improvements are necessary. Crash trends indicate that the most promising avenue to address the remaining real-world injuries is a higher severity vehicle-to-vehicle test using a barrier to represent a striking sport-utility vehicle (SUV). Laboratory tests comparing striking SUVs with the current IIHS moving deformable barrier (MDB) showed discrepancies in damage patterns and injury measures. The current study outlines the characteristics of a multi-stiffness aluminum honeycomb barrier to represent a modern SUV-striking vehicle in side impact crash tests. METHODS: Barrier size and shape were determined from a series of measurements taken from 21 modern SUVs. Barrier honeycomb stiffness characteristics were derived by comparing the damage profile of six different barrier prototypes against a baseline profile obtained from a high-severity SUV crash into a midsize car. Tests were conducted at 60 km/h with a 1,900 kg MDB. The best honeycomb design was tested against four additional vehicles to ensure it was representative of striking SUVs of different sizes and types. RESULTS: The final barrier has a 1,700-mm width by 600-mm height and 500-mm depth multi-stiffness design, with less stiffness on the top and more stiffness in the lower outside sections compared with the original IIHS barrier. For three struck vehicles, the redesigned barrier matched all performance criteria set by the striking-SUV tests. For two additional struck vehicles, there were some differences in intrusion patterns but overall, these matched the test trends of the striking SUVs. The new barrier in a higher severity test mode resulted in a range of performance for these good-rated vehicles. CONCLUSION: A multi-stiffness aluminum honeycomb barrier was developed to represent the characteristics of striking SUVs in 60 km/h perpendicular side impact crash tests focusing on the occupant compartment. The redesigned barrier differentiates between currently good-rated vehicles, which will promote structural and restraint system improvements to the fleet relevant to the remaining real-world injuries.

Occurrence of serious injury in real-world side impacts of vehicles with good side-impact protection ratings.

OBJECTIVE: The Insurance Institute for Highway Safety (IIHS) introduced its side impact consumer information test program in 2003. Since that time, side airbags and structural improvements have been implemented across the fleet and the proportion of good ratings has increased to 93% of 2012-2014 model year vehicles. Research has shown that drivers of good-rated vehicles are 70% less likely to die in a left-side crash than drivers of poor-rated vehicles. Despite these improvements, side impact fatalities accounted for about one quarter of passenger vehicle occupant fatalities in 2012. This study is a detailed analysis of real-world cases with serious injury resulting from side crashes of vehicles with good ratings in the IIHS side impact test. METHODS: NASS-CDS and Crash Injury Research and Engineering Network (CIREN) were queried for occupants of good-rated vehicles who sustained an Abbreviated Injury Scale (AIS) ≥ 3 injury in a side-impact crash. The resulting 110 cases were categorized by impact configuration and other factors that contributed to injury. Patterns of impact configuration, restraint performance, and occupant injury were identified and discussed in the context of potential upgrades to the current IIHS side impact test. RESULTS: Three quarters of the injured occupants were involved in near-side impacts. For these occupants, the most common factors contributing to injury were crash severities greater than the IIHS test, inadequate side-airbag performance, and lack of side-airbag coverage for the injured body region. In the cases where an airbag was present but did not prevent the injury, occupants were often exposed to loading centered farther forward on the vehicle than in the IIHS test. Around 40% of the far-side occupants were injured from contact with the struck-side interior structure, and almost all of these cases were more severe than the IIHS test. The remaining far-side occupants were mostly elderly and sustained injury from the center console, instrument panel, or seat belt. In addition, many far-side occupants were likely out of position due to events preceding the side impact and/or being unbelted. CONCLUSION: Individual changes to the IIHS side impact test have the potential to reduce the number of serious injuries in real-world crashes. These include impacting the vehicle farther forward (relevant to 28% of all cases studied), greater test severity (17%), the inclusion of far-side occupants (9%), and more restrictive injury criteria (9%). Combinations of these changes could be more effective.

Comparison of Hybrid III and THOR dummies in paired small overlap tests.

The Insurance Institute for Highway Safety (IIHS) is investigating small overlap crash test procedures for a possible consumer information program. Analysis of real-world small overlap crashes found a strong relationship between serious head and chest injuries and occupant compartment intrusion. The main sources of serious head injuries were from the A-pillar, dash panel, or door structure, suggesting head trajectories forward and outboard possibly bypassing the airbag. Chest injuries mainly were from steering wheel intrusion and seat belt loading. In developing this program, two test dummies were evaluated for predicting occupant injury risk: midsize male Hybrid III and THOR. In the collinear small overlap crash tests conducted here, results from the two dummies were similar. Both predicted a low risk of injury to the head and chest and sometimes a high risk of injury to the lower extremities. Head and torso kinematics also were similar between dummies. Other test scenarios might show larger differences between the dummies.

Comparison of EuroSID-2 and SID-IIs in Vehicle Side Impact Tests with the IIHS Barrier.

The Insurance Institute for Highway Safety (IIHS) has recently developed and evaluated a new side impact barrier to represent the front profile of pickup trucks and sport utility vehicles for a new consumer information program. In the development of this program, two dummies were considered for assessing driver injury risk in side-struck vehicles: EuroSID-2 (50th percentile male dummy) and SID-IIs (5th percentile female dummy). The purpose of this study was to compare injury responses and kinematics for these two dummies in side impact crash tests. The findings suggest that SID-IIs will be more effective in driving relevant improvements in side impact crash protection.