The University of Virginia Center for Applied Biomechanics conducted a parametric modeling study of seat performance in rear impact for the Insurance Institute for Highway Safety using OpenVT seat geometry, foam, and structure characteristics spanning real seats. Simulations compared BioRID and EvaRID dummy responses across multiple crash pulses. Some kinematic measures correlated between dummies, while most kinetic measures did not. EvaRID showed greater sensitivity to seatback foam stiffness and pre-crash braking effects than BioRID, with pre-pretensioner reducing several outcome measures.
IIHS is implementing virtual testing for whiplash prevention in rear-impact evaluation. A draft test protocol allowing ATD simulation submission was published in June 2025, with rating guidelines and auditing procedures following in December 2025. The evaluation uses metrics including head contact time, maximum NKM, upper neck tension, T1 x acceleration, and pelvis displacement at both 16 km/h and 24 km/h crash pulses. Small SUV ratings began in January 2026. Whiplash prevention with simulation option will be included in IIHS Top Safety Pick awards by February 2028. Future development includes human body model workflows and validation procedures.
A finite element model of the average female crash test dummy SET 50F v0.2 for low severity rear impact safety was developed through further tuning and evaluation of the FE SET 1.0.0 model to the FE SET 50F 2.0.0 model. Development included re-meshing of foam, fine tuning weights of body parts, drop tests on abdomen and torso foam, and static spine bending tests of thoracic-lumbar and cervical regions. The FE SET 50F 2.0.0 open-source model is available on the OpenVT platform.
EuroNCAP conducted whiplash tests using EVARID, a prototype dummy representing a 50%ile female based on BioRID II, on 2024 and 2025 seats with mid and high severity pulses. EVARID showed earlier head restraint contact time but shorter duration, higher NIC values in several cases, higher neck forces Fx and Fz, and higher pelvis and lumbar accelerations compared to BioRID II, indicating different dummy behavior. Next steps include repeatability and reproducibility testing, additional seat testing, evaluation of assessment criteria, and dummy certification.
Document discusses virtual testing research on rear impact occupant protection. CIDAS data from 132 rear-end collision cases involving 287 occupants shows female occupants comprise 34.15% of rear-impact cases, significantly higher than 21.25% across all accident types. Female passengers predominantly occupy rear seats at 46.95%. C-NCAP 2027 introduces whiplash virtual testing using EvaRID dummy for second-row seats alongside BioRID II for driver seats, with EvaRID injury limits 20% lower than BioRID II. Research includes dummy positioning adjustments and repeatability studies using ISO/TS 18571 evaluation methods.
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.
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.
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.
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