WHIPS (Volvo cars' Whiplash Protection System)-the development and real-world performance.

Objectives: Present the performance of WHIPS and identify possible next steps of soft tissue neck injury reduction potentials, based on rear-end real-world crash data.

Methods: Front-seat occupants (above 14 years of age) have been analyzed regarding influencing factors on reported incidences of soft tissue neck injuries. The outcome of 1858 occupants in cars equipped with WHIPS and 663 occupants in Volvo cars of model year 1999 without WHIPS are studied with respect to WHIPS injury-reducing effect for different impact severities and injury durations. The occupants in WHIPS are further studied with respect to seating position and sitting posture, such as turned head and head-to-head restraint distance.

Results: Soft tissue neck injury risk reductions are seen for occupants in WHIPS as compared to prior Volvo cars; mean values ranging from 21 to 47% depending on impact severity and symptom duration. Sitting posture (turned head and increased backset) increases soft tissue neck injury risks. Based on the self-reported injury data, a significantly lower risk was found for occupants facing straight forward with the head in close proximity to the head restraint as compared to the risk for occupants with rotated head and a larger backset. Even though the highest risk of soft tissue neck injuries is found in higher impact severity, the large amount of soft tissue neck injuries sustained at low impact severity emphasizes the need of focusing measures for crash avoidance.

Conclusions: This study presents the development and real-world performance of WHIPS as well as identifies situations for further focus and challenges for the next generation of soft tissue neck injury protection and prevention, including areas such as occupant posture and crash avoidance.