The EqOP Task Force 2 met online on 29-30 June 2026 to discuss whiplash protection in vehicle seats. Presentations covered whiplash injury mechanisms, UN R17 evaluation, C-NCAP 2027 virtual testing plans, EvaRID and BioRID dummy comparisons, IIHS Rear Impact 2.0 protocol development, parametric seat modelling, and validation of a female SET 50F FE model. Discussions concluded that regulations should avoid sub-optimization toward single criteria, dynamic testing better represents real-world conditions, head-restraint positioning should not be considered misuse, and more forgiving seat designs are needed. The next meeting is scheduled for 28 September 2026.

Whiplash remains a major concern following rear-end collisions, which account for 27.8% of passenger vehicle crashes. Females face greater risk of long-term cervical spine injury than males. Females have less muscle strength, more slender necks, and lower tolerance limits for lower neck shear force compared to males. Only one rear impact dummy size, the 50th percentile male, is currently available. Dynamic testing reveals differences in responses between 50th percentile female and male dummies. Whiplash mitigation requires reducing occupant acceleration, minimising relative movements between vertebrae, and minimising forward rebound. The seat must be considered as a system; focusing on one component alone is inadequate. Preparation for a future 50th percentile female rear impact dummy is recommended, with new injury thresholds established.

Field data shows reduction in risk for both males and females, though risk difference between males and females remains with higher risk for females regarding soft tissue neck injuries. Purely geometry-based assessment may not be sufficient; minimizing relative spine movements, forward rebound, evenness and energy absorption are important for equitable protection against whiplash. Discussion concluded that headrests often remain in highest position and do not protect occupants of lower stature optimally, which should not be considered misuse. A forgiving design of backrest and headrest should be targeted. Important to avoid suboptimization and assess more than one single point.

Whiplash injury causes neck pain, stiffness, headache, shoulder pain, and neurological symptoms, with women more sensitive than men. Symptoms occur consistently across rear, frontal, and lateral impacts. Research focuses on nerve injury in spinal ganglia as the injury site, as this explains why long term whiplash symptoms include neurological symptoms independent of crash direction. The Neck Injury Criterion (NIC) measures injury using the formula NIC = 0.2Δa + Δv², where Δa is acceleration difference and Δv is velocity difference. Whiplash motion causes rapid volume changes inside the vertebral canal, with epidural blood volume pumped to compensate. Animal experiments using pressure sensors show pressure changes in skull and spine at different vertebral levels during whiplash events.

Simulation of UN R17 whiplash protection component tests and rear impact sled tests using finite element models of a Toyota Auris seat showed the UN R17 test protocol is not robust. A modified seat model approved in component tests (displacement, strength, energy dissipation) but failed the dynamic performance test. Component tests allow large variation in seat properties and do not ensure approval of the dynamic performance test. Seat properties with large effects on whiplash protection in dynamic performance tests can vary substantially with minimal effects in component tests.