Rear seat occupant thorax protection in near side impacts

Abstract

Thoracic side-airbags (SAB) have proven to protect front seat occupants in side impacts. This benefit has not been evaluated for rear seat occupants who are typically small statured. The objective was to analyze field data from rear seat occupants in near side impacts, and evaluate the effect of a SAB in the rear seat, through full scale vehicle tests. A field study using the NASS-CDS database was performed to review rear seat crash characteristics, occupant injuries (Abbreviated Injury Scale 3+, AIS3+) and injury sources. Full scale tests were performed with the side impact dummy SID-IIs at two different crash severities, with and without SAB in a midsize passenger car. Field data showed that of all AIS3+ injured restrained occupants 13 years and older, 59% had AIS3+ thoracic injuries and 38% had AIS3+ head injuries. The thoracic injuries were distributed to lungs (60%), skeletal fractures (38%) and injuries to arteries (1,26%) and heart (0,1%). For AIS3+ injured children, age 4-12, 51% had AIS3+ thoracic injuries and 54% had AIS3+ head injuries. Compared to adults, children sustained less fractures and more lung injuries. The rear side interior was the main injury source regardless of age group. In the full scale tests, the thoracic side-airbag reduced the average rib deflection by 50% and resulted in an AIS3+ injury risk reduction from 36% to 3%. At the higher impact speed, SAB reduced the injury risk from 93% to 24%. The full scale crash tests showed that SAB offer a significant potential for thoracic injury reduction in the crash severities causing the majority of serious injuries in real life crashes.

Figure 1

Age distribution of restrained and unrestrained occupants.

Figure 2

Direction of force for restrained and unrestrained occupants.

Figure 3

Lateral DV for restrained and unrestrained occupants.

Figure 4

CDC crush extent for restrained and unrestrained occupants.

Figure 5

Lateral intrusion at the rear seat occupant compartment for restrained and unrestrained occupants.

Figure 6

Distribution of all AIS3+ injuries for occupants 13 years and older.

Figure 7

Percentage of MAIS3+ injured occupants 13 years and older with injuries to the different body regions.

Figure 8

Distribution of thoracic injury sources for occupants 13 years and older.

Figure 9

Distribution of all AIS3+ injuries for the age group 4–12 years.

Figure 10

Percentage of MAIS3+ injured occupants 4–12 years with injuries to the different body regions.

Figure 11

Distribution of thoracic injury sources for occupants 4–12 years.

Figure 12

Distribution of thoracic injury type divided by restraint use and age group.

Figure 13

SID-IIs average rib deflection in IIHS standard impact velocity test and in IIHS standard velocity+14 km/h test with and without thoracic side airbag.

Figure 14

SID-IIs maximum VC in IIHS standard impact velocity and IIHS standard velocity+14 km/h with and without thoracic side airbag.