Rear impact responses of 50th percentile female and male dummies in a seat with different whiplash injury risk reduction for women and men.

The aim of this study was to investigate the difference in rear impact dynamic response between a male and a female crash test dummy, in Saab 9-3 seats fitted with the Saab Active Head Restraint (SAHR) whiplash injury mitigation system. According to real world injury data, this SAHR system offers a greater risk reduction for the male population in comparison to the female. Identifying response differences between the male and female dummies, could explain the risk differences seen in real world crashes. Six sled tests were performed in Saab 9-3 seats (model year 1998-2002) in accordance with the European New Car Assessment Programme (Euro NCAP) whiplash test procedure (medium pulse, Δv 16 km/h, max acceleration 10 g). Two different low speed rear impact crash test dummies were used for the tests; the 50th percentile female prototype BioRID P50F_V2 and the 50th percentile male BioRID II. Both dummies exhibited early Head Restraint (HR) contact times which resulted in Neck Injury Criterion (NIC) values well below the recommended limit of 15 m2/s2. On the other hand, the NICprotraction values were almost two times greater for the female dummy in comparison to the male. In the Saab 9-3 seat, the SAHR system may cause a forward push to the head for average sized females, resulting in protraction of the neck rather than retraction. Current whiplash protection testing is performed with a 50th percentile male dummy. However, the results of this study show that in order to explain the sex differences found in real world data, it is necessary to use sex specific sizes of dummies developed for rear impact testing and include injury criteria to cover also flexion and protraction motion in the dynamic response. To cover the majority of the adult population, we recommend using the 50th percentile female and male dummies.