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.

The IWG EqOP held its 16th meeting on May 18, 2026, with 40 online participants from Contracting Parties and Industry. The agenda and minutes of the 15th meeting were approved. Three Task Forces—Rear-end assessment, Virtual crash testing, and Frontal impact and restraint systems—are operational with meetings planned in June 2026. A preliminary report to GRSP 79th session was presented and revised. Upcoming meetings include TF3 on June 11, TF4 on June 25, and TF2 on June 29-30. Each Task Force is invited to structure identified topics by prioritizing them and assigning short, medium, and long-term horizons, and to map contributions within the Task Force.

The agenda includes a workshop with two sessions addressing whether UNR17 dynamic testing should be mandatory and updates on ongoing research including CNCAP, Euro NCAP, EvaRID, BioRID, parametric study, and SET, discussion of a potential in-real-life workshop in October at BASt, and determination of the next meeting date.

The Equitable Occupant Protection informal working group pursues equitable and enhanced protection of diverse populations through robust, inclusive regulatory solutions addressing rear-end impact soft tissue neck injuries and frontal impact restraint systems. The group extends assessment towards brain injuries, soft tissue neck injuries, and lower extremity injuries with high frequency and risk of permanent medical impairment. Four task forces focus on rear impact seat assessment, virtual crash testing, frontal impact and restraint system requirements, and assessment of currently not considered injury types. Workshops are scheduled for June 29-30 on rear impact assessment, September 7 in Munich on virtual crash testing, and November 4-6 in Tokyo on frontal impact.

The Equitable Occupant Protection Informal Working Group to GRSP pursues equitable and enhanced protection of a diverse population through robust regulatory solutions addressing rear-end and frontal impacts. Strategic goals include reducing injury risk for restraint systems, assessing currently not considered injury types with high frequency and risk of Permanent Musculoskeletal Impairment, and avoiding bias in protection. The group established task forces on rear impact seat assessment focusing on soft tissue neck injuries, virtual crash testing, frontal impact and restraint system requirements, and extension of assessment towards currently not considered injury types. Upcoming workshops are scheduled for June online, September in Munich, and November in Tokyo. Next steps include prioritization and categorization of identified topics into short-term, mid-term, and long-term timeframes within respective task forces.

The draft agenda for the 5th meeting of Task Force 4 Frontal Impact & Restraint System Requirements is scheduled for June 25, 2026, online from 12.00 to 14.00 CET. The meeting will cover approval of the agenda and previous minutes, review of the progress dashboard, presentations of updated studies on abdominal injuries and rear row, continued discussion on priorities, a workshop in Japan, conclusions, next steps, the next meeting, and any other business.

The EqOP-TF4 held its 4th meeting on 14 April 2026 with 28 participants. BASt presented an updated GIDAS analysis of abdominal injuries in belted occupants with single major impacts. The Swedish Transport Agency presented an updated study on occupant abdominal trauma including pelvic fractures and injury severity by age and seatbelt effects. OICA presented French collision data from 2012 to 2024 showing rear seats are significantly less utilized and the front row represents 96% of fatalities and most serious injuries in M₁ passenger cars. The Chair and secretary will compile input on priorities. The next meeting is scheduled for 25 June 2026, with an in-person workshop planned for 4–6 November 2026 in Japan.

From 2006 to 2025, Swedish emergency hospitals treated 170,995 injured drivers and passengers in passenger cars (52% men, 48% women). Pelvic fractures occurred in 1,198 individuals (0.7%), with 78% having one fracture and 22% having multiple fractures. The proportion of pelvic fractures increased with age and when seat belts were not used. Drivers comprised 71% of injured, front passengers 14%, and rear passengers 8%.

GIDAS data analysis examined abdominal injuries in car crashes from 2005–2025. Case selection included passenger cars registered 2005–2025, occupants over 11 years old, belted, with at least AIS 1 in AIS15REG5. The study analyzed 234 cars with 248 occupants sustaining abdominal injuries. Frontal impacts accounted for 71%, rear impacts 12%, left side impacts 10%, and right side impacts 8% of cases. Analysis examined injury distribution across AIS levels, gender, age, height, weight, delta V, seating position, and specific abdominal injuries.

This accidentology study analyzed French national accident data from 2015–2024 for M₁ vehicles involved in frontal collisions. Overall occupancy rate was 1.4 persons per vehicle, with rear rows accounting for 11% of occupants. Rear right seats were most occupied (46%), followed by rear left (40%) and rear centre (12%). Fatalities occurred in 96% of front row occupants versus 4% in rear rows. Rear row occupants showed consistently lower severity outcomes across all injury categories compared to front row occupants, with no significant differences observed before or after 2020.

The informal working group on Equitable Occupant Protection will hold its 16th meeting on 18 May 2026 from 10.00 to 12.00 CET via TEAMS. The preliminary agenda includes adoption of the agenda, approval of minutes from the 15th meeting, review of the Progress Dashboard, status review of task forces, a report to GRSP 79th session, discussion of upcoming meetings and workshops, and conclusion.

The IWG chair reviewed the 15th meeting to address strategic goals of equitable and overall enhanced protection of diverse populations in rear-end and frontal impacts, based on feedback from GRSP-78-07 and GRSP-78-08. Task forces are investigating submarining prevention, abdominal injury risks, Diffuse Axonal Injuries, lower extremity injuries, and neck injuries in frontal crashes, while considering occupants of different sizes, weights, shapes, and seat adjustments. Priorities include developing broader protection procedures over a range of scenarios and speeds rather than specific repeated requirements, with next steps involving prioritization and role definition within task forces before reporting to GRSP 79.

The 15th meeting of the UN GRSP IWG Equitable Occupant Protection was held on March 24, 2026, with 35 online participants. The agenda and minutes of the 14th meeting were approved. Two informal documents, GRSP-78-07 and GRSP-78-08, were presented to GRSP 78 and discussed. Three operational Task Forces on rear-end assessment, virtual crash testing, and frontal impact and restraint systems were reviewed. Each Task Force is invited to structure identified topics by prioritizing them and assigning a short, medium, or long-term horizon, and to map contributions within the Task Force clarifying roles and areas of expertise. The 16th IWG online meeting is scheduled for May 18, 10–12 CEST.