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Senior and obese occupants in traffic accidents

Senior and obese occupants in traffic accidents. Safety Vehicle – Safety Passenger Krakow 11 – 12 April, 2019 [Previous subject at 2017 conference: Safety of Traveling Children and Disabled People]. Summary of previous presentation: Why is the infant/child safety necessary?.

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Senior and obese occupants in traffic accidents

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  1. Senior and obese occupants in traffic accidents Safety Vehicle – Safety Passenger Krakow 11 – 12 April, 2019 [Previous subject at 2017 conference:Safety of Traveling Children and Disabled People]

  2. Summary of previous presentation: Why is the infant/child safety necessary? • Road vehicles are designed to 50 percentile adults. Safety devices used by adults can’t be used by children due to differences in size and physiology • Main problems • Child injury criteria and mechanical tolerances of children. Due to social and ethical reasons experimental ways of its investigation are limited • Due to obvious reasons volunteer tests are not an option • Cadaver testing is rare • “biofidelic” mechanical and computer models of child occupant • Child restraint system: in some countries lack of knowledge how children can be protected in accidents • Current situation • Mechanical properties if tissues of the child body are not enough determined (roughly 4 times lower than these of adults)The head and the neck injuries are the most frequent (disconnection between the head and the neck) [2017 conference: Safety of Traveling Children and Disabled People]

  3. Summary of previous presentation: Neck • Strength of neck muscles increases with age • Neck vertebrae of children are immature models of adults • Atlas (C1) and axis (C2) don’t fully developed until age of 4 to 6 • Intervertebra joints’ facets are nearly horizontal (weak support) cartilage —> slowly —> slowly—>bonny structure • Neck ligaments are weaker than in adults • Infants can be subjected to uncontrolled and passive cervical spine movements, and compressive or distraction forces due to impact deceleration + large head [2017 conference: Safety of Traveling Children and Disabled People]

  4. Summary of previous presentation: Regulations general • Motor Coach/Bus (MCB) regulations vary significantly across continents and countries. • Europe’s ECE/R66 is the most comprehensive for testing and Australia’s ADR 59/00 for seats, belts and anchorages. Australia and South Africa’s SANS 1038 are good, but could use an upgrade to include occupant mass in the superstructure compliance calculation. The US and Canada seem to be starting to recognize the value of seat belts and rollover structural regulations and … new Motor Coach Safety Provisions will help rectify the shortcomings in the regulations. Peru and Chile have some basic regulations for occupant protection …. • Other: EC Directives 74/408/EC "Seat Anchorages", 76/115/EC "Seat Belt Anchorages" and 77/541/EC "Seat Belts" Bozzini et.al. 23th ESV 2013. “Examination and Comparison of Passenger Transport Bus Occupant Protection Regulations Across 5 Continents” [2017 conference: Safety of Traveling Children and Disabled People]

  5. Summary of previous presentation: Regulations: child safety in buses/coaches • During 2006: 12 EU countries has come into force the European Directive 2003/20/CE* that encourage the usage of child restrain systems and safety belts in all vehicle types including Class II and III buses. • * - DIRECTIVE 2003/20/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 8 April 2003 amending Council Directive 91/671/EEC on the approximation of the laws of the Member States relating to compulsory use of safety belts in vehicles of less than 3,5 tonnes • Economic Commission for Europe of the United Nations (UN/ECE 1958 agreement) ECE/TRANS/WP.29/78/Rev.3 [2014] • Regulation 44: Uniform provisions concerning the approval of restraining devices for child occupants “Child Restraint Systems” (CRS) • Regulation 129: “Enhanced Child Restraint Systems” (ECRS) Martínez l. et.al. 2011. Child frontal impact safety in coaches. 22 ESV-000383 [2017 conference: Safety of Traveling Children and Disabled People]

  6. Summary of previous presentation: R44 vs R129 (minimal level of protection) Regulation 44: Child Restraint Systems (CRS) Regulation 129: Enhanced Child Restrain System (ECRS) Stature based classification Size ranges (not fixed) Universal / vehicle specific Rearward facing < 15 m Q‐dummies Side impact test Improved car compatibility • Mass based classification • Fixed weight groups • (semi)Universal / vehicle specific • Forward facing > 9kg • P dummies • No side impact test [2017 conference: Safety of Traveling Children and Disabled People]

  7. Summary of previous presentation: Belt rules in Sweden • All bus passengers older than three years shall be seated in a chair with seat belt, if there is such a seat, and shall use the belt. The Transport Agency recommends that even younger children use the seat belt or special protective device. If there is no seat with seat belt available, it is allowed to stand in the bus (if the bus is approved for this). • The person sitting in a wheelchair should sit in a wheelchair and wear a seat belt if there is. The wheelchair shall be fitted with or supported by a device intended for it in the vehicle. The driver, other boarding staff, escort and leader of a group shall help the passenger with this. [2017 conference: Safety of Traveling Children and Disabled People]

  8. Summary of previous presentation: Safety of passenger using wheelchair - standards • Regulations for Automotive Applications • Regulation 107 of the Economic Commission for Europe of the United Nations (UN/ECE) 2006 - Uniform Provisions Concerning the Approval of Category M2 or M3 Vehicles with Regard to Their General Construction. (comment: busses, general requirements) • ANSI/RESNA WC19: Wheelchairs Used as Seats in Motor Vehicles [US] (American National Standard Institute/ Rehabilitation Engineering and Assistive Technology Society of North America) • ANSI/RESNA WC20: Wheelchair Seating Systems for Use in Motor Vehicles [US] • ANSI/RESNA WC18: WTORS - Wheelchair Tiedown and Occupant Restraint Systems for Use in Motor Vehicles [2017 conference: Safety of Traveling Children and Disabled People]

  9. Summary of previous presentation: Safety of passenger using wheelchair – standards cont. • ISO 7176-19:2008 Wheelchairs - Wheeled mobility devices for use as seats in motor vehicles (forward-facing) • A voluntary industry standard • harmonized with WC/19 The belt is not held off the body of any part of the wheelchair such as armrests and wheels. Wheelchair with 4-points securement (tiedown) system and 3-point belt for the user [2017 conference: Safety of Traveling Children and Disabled People]

  10. Senior or obese occupants in traffic accidents (bus and coach) - Accident data - Biomechanical data - Modeling of human in crash situations

  11. Accident – dataMain trends

  12. Road accident fatalities by category of vehicles, EU-28, 2016 EUROSTAT. Fatal road accidents in the EU, 2016

  13. Percentage change in number of fatalities by mode of transport in the EU, 2015 and 2006 CARE (EU road accidents database) or national publications. 2017

  14. Road fatality rates per million population by age group and gender, EU, 2015 or latest available year Sources: CARE database (EUROSTAT for population data), data available in May 2017 European Road Safety Observatory (ERSO). Traffic Safety Basic Facts.

  15. Fatalities per billion kilometers travelled in the Netherlands 2001-2005. Source: Dutch Ministry of Transport/Statistics Netherlands

  16. Biomechanics – basic data

  17. Peak bending moment at fracture for statically loaded wet tibias*(Based on data of Yamada 1970)

  18. Results of proximal tibial impact tests(Based on data of Viano et al. 1978)

  19. Bone Mineral Content (BMC) • Invasive technique: • iliac crest bone biopsy (BX). • Non-invasive techniques: • single and dual photon absorptiometry (SPA and DPA) • quantitative digital radiography (QDR) • computed tomography (CT) • radiographic photodensitometry (RD) • radiogrammetry (RG) • total body calcium by neutron activation analysis (TBC-NAA) • ultrasound (US)

  20. Coefficient of correlation (r) between ultimate bending moment at failure and different biological parameters of lumbar FSU

  21. Coefficient of correlation (r) between BMC and different ultimate biomechanical properties of lumbar FSU

  22. Global obesity problem Most widely-used method of measuring and identifying obesity is Body Mass Index (BMI). This is weight in kilograms divided by the height in meters squared. World Obesity 2018

  23. Global obesity problem Percentage of adults with BMI > 30 Obesity is a modern problem - statistics for it did not even exist 50 years ago. WHO 2005

  24. Key facts • Worldwide obesity has nearly tripled since 1975. • In 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese. • 39% of adults aged 18 years and over were overweight in 2016, and 13% were obese. • Most of the world's population live in countries where overweight and obesity kills more people than underweight. • 41 million children under the age of 5 were overweight or obese in 2016. • Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016. WHO 2018

  25. Methodology of injury investigation • Volunteer testing • Cadaver testing • Animal testing • Computer testing • Dummy testing • Combination of above • Accident investigation • Accident reconstruction

  26. Depot sites of adipose tissue and the anatomy Hosein Naseri. 2017 Thesis: Calibration and Modelling of Adipose Tissue Under Impact Loading. Department of Mechanics and Maritime Sciences, Chalmers University of Technology

  27. Modelling of adipose tissue under impact loading – Constitutive Model • nearly incompressible material • strain energy is split further into volumetric and deviatoric parts • neo-Hookean material model considered for deviatoric parts while a simple function represents the volumetric strain energy • …. Hosein Naseri. 2017 Thesis: Calibration and Modelling of Adipose Tissue Under Impact Loading. Department of Mechanics and Maritime Sciences, Chalmers University of Technology

  28. Adipose tissue properties under impact loading The amount of compressibility highly affects the behavior of adipose samples in high rates. It is important specially when studying how adipose tissue behavior affects the dynamics of obese occupant responses during crash situations. Crucialquestion How should current injury criteria be changed to incorporate obesity effects? Hosein Naseri. 2017 Thesis: Calibration and Modelling of Adipose Tissue Under Impact Loading. Department of Mechanics and Maritime Sciences, Chalmers University of Technology

  29. Morphed GHBMC human models of different stature, BMI, and age GHBMC – Global Human Body Model Consortium Jingwen, Hu. et.al. 2016. Vehicle Crash Simulations with Morphed GHBMC Human Models of Different Stature, BMI, and Age. Proceedings, 4th International Digital Human Modeling Conference. 2016. Montreal, Canada.

  30. Various morphed GHBMC models Jingwen, Hu. et.al. 2016. Vehicle Crash Simulations with Morphed GHBMC Human Models of Different Stature, BMI, and Age. Proceedings, 4th International Digital Human Modeling Conference. 2016. Montreal, Canada.

  31. Examples of kinematics from occupants with different characteristics Jingwen, Hu. et.al. 2016. Vehicle Crash Simulations with Morphed GHBMC Human Models of Different Stature, BMI, and Age. Proceedings, 4th International Digital Human Modeling Conference. 2016. Montreal, Canada.

  32. Ribcage stress history – example of the complexity of influences • Stress distribution in heaver occupants is higher on ribs where the shoulder belt is routed • Load from the seatbelt caused more deformation in load-bearing ribs instead of increased sternal displacement relative to the thoracic spine • This effect caused low chest deflections in heavier and older HBMs • However, older occupants sustained higher chest and femur injury risks mainly due to their lower injury tolerance and increased adipose tissues around the abdomen compared to young occupants with similar BMI and stature Jingwen, Hu. et.al. 2016. Vehicle Crash Simulations with Morphed GHBMC Human Models of Different Stature, BMI, and Age. Proceedings, 4th International Digital Human Modeling Conference. 2016. Montreal, Canada.

  33. Comparison of impact kinematics between test subjects and the obese occupant model (THUMS Version 4 AM50 occupant model) Kitagawa Y. et.al. 2017. Comparison of Impact Kinematics between Non‐obese and Obese Occupants in Frontal and Lateral Impacts. IRCOBI 2017

  34. Comparison of lap belt – pelvis interactions between non‐obese and obese occupants Kitagawa Y. et.al. 2017. Comparison of Impact Kinematics between Non‐obese and Obese Occupants in Frontal and Lateral Impacts. IRCOBI 2017

  35. Identified injury risk trends due to different body sizes and BMI • Taller occupants tended to have a higher risk of head injuries • Higher BMI occupants tended to have higher injury risk • Older occupants tended to have higher injury risks due to their lower injury tolerance • Obese occupant exhibited a greater forward excursion than the non‐obese in the frontal impact • Pelvis engagement by the lap belt was delayed due to the thick soft tissue of the abdomen • Simulations were only based one generic vehicle and the results may not be generalized for the whole fleet • Occupant characteristics had extensive and complex impact in injury risks Jingwen, Hu. et.al. 2016 and Kitagawa Y. et.al. 2017.

  36. Further validation of the performance of the obese GHBMC models • Obese GHBMC models were evaluated with respect to the available PMHS studies • Lap belt pull tests were used to evaluate belt interaction with the model’s abdomen and pelvis • Adipose tissue‐level tests were used to evaluate the shear stiffness of the flesh material model used in the obese HBMs Gepner, BD. et.al. (2018) Performance of the Obese GHBMC Models in the Sled and Belt Pull Test Conditions. IRCOBI

  37. Gepner, BD. et.al. 2018 conclusions • The obese GHBMC models failed to replicate the submarining behavior and restraint kinematics observed in the PMHSs in rear‐seat sled tests. • The obese GHBMC models failed to replicate the belt trajectory observed in the belt pull tests; belt sliding up over the iliac wings and into the abdomen. • The GHBMC flesh material model exhibits a much stiffer stress/strain response in shear compared to human abdominal subcutaneous adipose tissue data from the literature. • The obese HBMs could be useful tools, however improvement of biofidelity of the models necessary. THUMS Gepner, BD. et.al. (2018) Performance of the Obese GHBMC Models in the Sled and Belt Pull Test Conditions. IRCOBI

  38. SAFETY ENHANCED INNOVATIONS FOR OLDER ROAD USERS EUROPEAN COMMISSION EIGHTH FRAMEWORK PROGRAMME HORIZON 2020 GA No. 636136 Major factors that influence the safety of older road users, as car occupants, pedestrians or cyclists in road traffic crashes.

  39. SENIORS project overview

  40. SENIORS project Implemented in a project structure, the SENIORS project consists of four technical Work Packages (WP1 – WP4) which interact and will provide the knowledge needed throughout the project. WP1: Accidentology and behavior of elderly in road traffic WP2: Biomechanics WP3: Test tool development WP4: Current protection and impact of new safety systems In addition, there is one Work Package assigned for the Dissemination and Exploitation (WP5) as well as one Work Package for the Project Management (WP6).

  41. SENIORS – Public deliverablesAccidentology SENIORS 1.1 - Behavioural aspects of elderly as road traffic participants and modal split SENIORS 1.2 - Road traffic accidents involving the elderly and obese people in Europe incl. investigation of the risk of injury and disabilities SENIORS 1.3 - Road Safety measures towards the elderly, Effects of active vehicle safety systems and derivation of safety strategies

  42. SENIORS WP1 – Databases used EUROPEAN ACCIDENT STATISTICS IRTAD - International Road Traffic and Accident Database CARE - Community Database on Accidents on the Roads in Europe NATIONAL ACCIDENT STATISTICS STRADA - Swedish TRaffic Accident Data Acquisition DESTATIS - German Official Road Accident Data ACI-ISTAT - (Automobile Club d’Italia - Istituto nazionale di STATistica) DGT (Direción General de Transito) - Spain STATS19 - Great Britain

  43. SENIORS WP1 – Databases used (cont) IN-DEPTH DATA SOURCES GIDAS - German In-Depth Accident Study iGLAD - Initiative for the Global Harmonization of Accident Data Project created in 2010 by European car manufacturers RAIDS - Road Accident In-Depth Studies UK Department for Transport US DATA NASS GES - National Automotive Sampling System General Estimate Systems NASS CDS - National Automotive Sampling System Crashworthiness Data System (U.S. DoT) CIREN - Crash Injury Research and Engineering Network

  44. SENIORS WP1 – Databases used (cont) HOSPITAL DATA TraumaRegister DGU (German Trauma Society) – all injouries TARN - Trauma Audit and Research Network (UK) Hospital data from Barcelona Salerno Hospital data (Ruggi d’Aragona - Italy) STRADA matched with hospital records RITG - Registro Nazionale Traumi Gravi (Italian Register of Severe Trauma)

  45. WP1 – The injury overview for car occupants in STRADA (N = 49,125)

  46. WP1 – Probability of thorax injury severity (mAIS) for mid-aged and older car occupants in frontal collisions, GIDAS, cars from 2005 Etc…

  47. SENIORS – Public deliverables (cont) SENIORS 2.1 - Biofidelity Requirements for Older and Obese Car Occupants and External Road User Surrogates SENIORS 2.2 - Part A - Muscle Activity in a Non-injurious Sled Test Programme SENIORS 2.2 - Part B - Virtual Reality for Driver Pre-Crash Response Analysis SENIORS 2.3 - Kinematic comparison between the THOR dummy, older volunteers and older PMHS in low-speed non-injurious frontal impacts SENIORS 2.4 - Updated Human Body Models representing elderly occupants and pedestrians (incl. overw./obese) SENIORS 2.5 - Updated injury criteria for the (a) THOR and (b)pedestrian test tools

  48. SENIORS – Public deliverables (cont) SENIORS 3.1a - Design specifications for an Elderly Overweight Dummy SENIORS 3.1b - Design Specifications For Improved Pedestrian Tools SENIORS 3.2a - Elderly Overweight Dummy Test and Validation SENIORS 3.2b - Updated Impactor Test and Validation Report SENIORS 3.3a - Elderly Overweight Dummy Certification SENIORS 3.3b - Updated Pedestrian Impactor Certification SENIORS 3.4a - Validated Elderly Overweight Dummy SENIORS 3.4b - Validated updates to pedestrian impactors for testing

  49. SENIORS – Public deliverables (cont) SENIORS 4.1a - Draft Test and assessment procedure for current and advanced passive car occupant safety systems SENIORS 4.1b - Draft Test and Assessment Procedures for current and advanced Passive VRU Safety Systems SENIORS 4.2a - Evaluated Test and Assessment Procedures for current and advanced passive Elderly Occupants Safety Systems SENIORS 4.2b - Evaluated Test and Assessment Procedures for current and advanced passive VRU Safety Systems SENIORS 4.3 - Benefit analysis

  50. Interesting sources

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