Biomechanics
Overview
NHTSA’s Biomechanics Research Divisions (Human Injury Research; Applied Biomechanics) conduct cooperative and collaborative research with other organizations around the world to develop knowledge and tools that help mitigate injury and death from motor vehicle crashes. Efforts include collection and analysis of real-world injury data, development and evaluation of advanced testing and simulation tools such as crash test dummies and human body models as well as the maintenance of NHTSA’s fleet of crash test dummies.
Field and Crash Data
NHTSA collects and analyzes real-world crash data to identify and prioritize issues that are most urgent for crash safety research.
Crash Injury Research and Engineering Network
Future of Crash Safety
- FoCS Overview Poster
- Crashes and Injuries in 2020-2030: Development of a Crash Data Projection Model
- Methods Used to Develop a Model For Crash and Injury Projections For 2020–2030
- Projections of Passenger Vehicle Crashes and Occupant
Other Data Sources
Human Response and Injury Research
NHTSA supports and/or executes injury research that documents the human response and tolerance to the forces that vehicle occupants and other road users experience as a result of motor vehicle crashes.
Head/Brain
According to the Centers for Disease Control and Prevention (CDC) traumatic brain injury is an important public health problem in the United States. TBI is frequently referred to as the “silent epidemic” because the complications from TBI, such as changes that affect thinking, sensation, language, or emotions, may not be readily apparent. The most recent CDC report (Frieden et al., 2010) estimates 1.7 million people sustain a TBI annually; of them 52,000 die. The report finds that among all age groups, motor vehicle-traffic (MVT) was the second leading cause of TBI (17.3%) and resulted in the largest percentage of TBI-related deaths (31.8%). To address this issue NHTSA developed a brain injury criterion (BrIC) that incorporates head rotational velocity measurements instead of the translational acceleration measures used in current regulated head injury criterion (HIC).
- Development of Brain Injury Criteria (BrIC) (Stapp Car Crash Journal, 2013)
SIMon Software and Reports
- SIMon FE Keyword Model
- SIMon: Simulated Injury Monitor
- Injury Assessment Tools (NFL Symposium, 2016)
- Brain Injury Mechanisms - Simplified (Biomechanics of Traumatic Brain Injury of the Stapp Conference, 2015)
- A Modern Perspective on Historical Brain Injury Research (IRCOBI, 2015)
- Kinematic Rotational Brain Injury Criterion (ESV, 2011)
- Investigation of Traumatic Brain Injuries Using the Next Generation of SIMon Finite Element Head Model (Stapp Car Crash Journal, 2008)
- On the Development of the SIMon Finite Element Head Model (Stapp Car Crash Journal, 2003)
Among head injuries in motor vehicle crashes, subdural hematomas (SDH) are both frequent and life-threatening, especially for older occupants. NHTSA is conducting research to determine SDH injury tolerance for older occupants with a focus on evaluation of the increasing risk of bridging vein failure with age. Our research on SDH includes crash data investigation on injuries in the field, development of a relationship between brain atrophy and age, development of methods to slow brain tissue degradation, and high-rate rotation tests of post-mortem human subject heads while measuring motion at the surface of the brain using ultrasound.
Resources and Reports
- Head Injury and Aging: The Importance of Bleeding Injuries (Association for the Advancement of Automotive Medicine Conference Proceedings, 2010)
- Subdural Hematoma and Aging: Crash Characteristics and Associated Injuries (ESV, 2011)
- Measurement of Meningeal Motion Using B-Mode Ultrasound as a Step Toward Understanding the Mechanism of Subdural Hematoma (2013)
- High-Frequency B-Mode Ultrasound for the Measurement of Intracranial Motion in Head Rotation (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2015)
- The Relationship of Brain Atrophy and Age to Aid in Subdural Hematoma Injury Risk Prediction (Injury Biomechanics Symposium, 2017)
- Developing a Method of Slowing Brain Tissue Degradation through Temperature, Sodium Bicarbonate and Antibiotics for Traumatic Brain Injury Testing (Injury Biomechanics Symposium, 2017)
- Addressing Spatiotemporal Distortion of High-speed Tissue Motion in B-mode Ultrasound (Biomedical Physics & Engineering Express, 2018)
- Potential Tools for Delaying Degradation of Brain Tissue Properties in PMHS Testing (SAE, 2018)
- Quantifying Relative Brain Motion in a Post Mortem Human Subject (Injury Biomechanics Symposium, 2019)
The capability of accurately measuring the head kinematics in motor vehicle crash conditions is important for assessing brain injuries as well as head-neck loads and kinematics often associated with whiplash-like injuries in rear impacts.
Resources and Reports
- Measurement of Head Kinematics in Impact Conditions Using a Coplanar 6aw Configuration (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2015)
Neck/Spine
NHTSA has supported a number of research efforts focused on the neck/cervical spine. The emphasis of those studies has been on injury tolerance and response in conditions relevant to motor vehicle crashes. Our most recent efforts are focusing on data collection to support enhanced biofidelity assessment of advanced anthropomorphic test devices (ATDs).
+ Resources and Reports
While much research has been done on cervical spine (neck) biomechanics to provide design targets for ATD necks, less is known about the transition between the lower cervical spine and upper thoracic spine. NHTSA has conducted research to determine response requirements for this body region.
+ Resources and Reports
- Sequential Biomechanics of the Human Upper Thoracic Spine and Pectoral Girdle (Association for the Advancement of Automotive Medicine, 2012)
- Dynamic Properties of the Upper Thoracic Spine-Pectoral Girdle System and Corresponding Kinematics in PMHS Sled Tests (Stapp Car Crash Conference, 2012)
- PMHS Lower Neck Load Calculation using Inverse Dynamics with Cervical Spine Kinematics and Neck Mass Properties (IRCOBI, 2016)
- Head and Neck Responses of Post Mortem Human Subjects in Frontal, Oblique, Side and Twist Scenarios (IRCOBI, 2018)
Lumbar Spine
Studies of real-world crash cases, including those in CIREN, identified injuries to the lumbar spine in what would otherwise be considered planar crashes absent significant vertical loading. NHTSA has supported research to better document the mechanisms of these lumbar spine fractures and is currently supporting research looking at lumbar spine response of reclined occupants.
+ Resources and Reports
- Thoracolumbar Spine Fractures in Frontal Impact Crashes (Annals of Advances in Automotive Medicine, 2012)
- Burst Fractures of the Lumbar Spine in Frontal Crashes (Accident Analysis and Prevention, 2013)
- Biomechanics of Lumbar Motion Segments in Dynamic Compression (Stapp Car Crash Conference, 2017)
Shoulder
Lateral and Oblique Response and Injury Tolerance
The shoulder is an important load path in lateral and oblique crashes. NHTSA has conducted research to develop response requirements and determine injury tolerance in this loading mode, which is important for side impact ATD design.
+ Resources and Reports
- Shoulder Response Characteristics and Injury Due to Lateral Glenohumeral Joint Impacts (Stapp Car Crash Conference, 2000)
- Shoulder Impact Response and Injury Due to Lateral and Oblique Loading (Stapp Car Crash Conference, 2003)
Little is known about the response of the pediatric human shoulder; therefore, biofidelity of child ATD shoulder designs is difficult to evaluate. NHTSA is conducting research with pediatric volunteers in quasistatic conditions to generate the necessary data to provide design direction for child-size ATDs.
+ Resources and Reports
Thorax
Thorax injuries remain prevalent in frontal crashes. In addition, females may have greater risk of thorax injury than males in a comparable crash. NHTSA has conducted testing using small female post-mortem human subjects (PMHS) to study the injury tolerance of females in realistic, simulated crash conditions. The aim of this work is to inform development of tools, such as advanced female ATDs, that can be used to improve vehicle safety.
+ Resources and Reports
- Small Female/Older Occupant Thoracic Biofidelity Corridor Development (NHTSA, 2019)
- Small Female Ribcage Fracture in Frontal Sled Tests (Traffic Injury Prevention, 2016)
As crash occupants can be loaded from virtually any direction, it is important to know injury tolerance and response in multiple directions.
+ Resources and Reports
- Oblique and Lateral Impact Response of the PMHS Thorax (Stapp Car Crash Conference, 2006)
- Response of PMHS to High- and Low-Speed Oblique and Lateral Pneumatic Ram Impacts (Stapp Car Crash Conference, 2011)
- PMHS Thorax Response in Low- and High-Speed Oblique and Lateral Ram Impacts (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2013)
- Response of the PMHS Thorax in Lateral and Oblique Pneumatic Ram Impacts – Investigation of Impact Speed, Impact Location, and Impact Face (IRCOBI, 2014)
NHTSA documented a deformation or deflection energy approach for normalizing PMHS response data for use in developing biofidelity corridors.
+ Resources and Reports
- An Improved Normalization Methodology for Developing Mean Human Response Curves (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2008)
- A Deformation Energy Approach to Normalizing PMHS Response Data and Developing Biofidelity Targets for Dummy Design (IRCOBI, 2014)
- An Improved Deflection Energy Method to Normalize PMHS Thoracic Response Data (IRCOBI, 2017)
- An Improved Normalization Methodology for Developing Mean Human Response Curves (ESV, 2013)
Thorax injuries, and specifically rib fractures, occur often in motor vehicle crashes. NHTSA is conducting research on human rib specimens to understand how ribs respond in bending, and why rib response and fracture tolerance varies across the population. The ultimate goal of this work is to come up with a way to estimate injury tolerance based on rib structural characteristics identified from an individual’s rib geometry. This would have implications for adaptive restraint design in vehicles.
+ Resources and Reports
- Biomechanical Properties of the Excised Pediatric Human Rib (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2007)
- Age-Related Changes in Stiffness in Human Ribs (IRCOBI, 2013)
- The Response of Pediatric Ribs to Quasi-Static Loading: Mechanical Properties and Microstructure (Ann Biomed Eng, 2013)
- Tensile Stress in Human Ribs Throughout the Lifespan (IRCOBI, 2014)
- The Effect of Age on the Structural Properties of Human Ribs (J Mech Behavior Biomed Mat, 2015)
- Establishing a Hierarchical Approach to Explore Biological Contributors to Dynamic Response and Failure in the Human Thorax (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2016)
- Age and Sex Alone Are Insufficient to Predict Human Rib Structural Response to Dynamic AP Loading (J Biomechanics, 2016)
- The Effect of Body Size on Adult Human Rib Structural Properties (IRCOBI, 2017)
- Variance in Fracture Location of Human Ribs Subjected to Dynamic Antero-Posterior Bending (IRCOBI, 2017)
- Quantification of Skeletal and Soft Tissue Contributions to Thoracic Response in a Dynamic Frontal Loading Scenario (Stapp Car Crash Conference, 2018)
- Sources of Variability in Structural Bending Response of Pediatric and Adult Human Ribs in Dynamic Frontal Impacts (Stapp Car Crash Conference, 2018)
- Human Rib Fracture Characteristics and Relationships with Structural Properties (IRCOBI, 2019)
- Evaluation of Skeletal and Soft Tissue Contributions to Thoracic Response of GHBMC M50-O Model in Dynamic Frontal Loading Scenarios (IRCOBI, 2019)
- A New Scaling Method for Age-, Sex-, and Body Size-Dependent Thoracic Responses using Structural Properties of Human Ribs (Stapp Car Crash Conference, 2019)
- Characterization of Strain Mode in Human Ribs Subjected to Anterior‐Posterior Loading (IRCOBI, 2020)
- Characteristics of Vulnerable Occupants Predicted by Rib Structural Properties (IRCOBI, 2020)
- Preliminary Methods for Modeling Stress‐Strain Curves of Human Ribs from Structural Dynamic Bending Tests (IRCOBI, 2020)
- Viscoelastic Properties of Human Ribs in a Simulated Frontal Impact (IRCOBI, 2020)
- A Hierarchical Exploration of Rib Strain in Dynamic Frontal Impacts of Thoraces (IRCOBI, 2020)
- Biomechanical Response Targets of Adult Human Ribs in Frontal Impacts (Annals of Biomedical Engineering, 2020)
Abdomen
NHTSA is developing response corridors for ATD abdomens and deriving injury risk functions using pressure, which has practical advantages over measuring displacement in soft abdomen components.
+ Resources and Reports
- Using Vascular Pressure to Estimate Blunt Liver Injury Risk (Stapp Car Crash Conference, 2007)
- Development of a Fluid-Filled Catheter System for Dynamic Pressure Measurement in Soft Tissue Trauma (International Journal of Crashworthiness, 2008)
- Pressure-Based Abdominal Injury Risk Using Isolated and Full Body Human Liver Impacts (Stapp Car Crash Conference, 2011)
- Biomechanical Responses of PMHS Subjected to Abdomen Seatbelt Loading (Stapp Car Crash Conference, 2016)
- Evaluation of Sex Specific Abdominal Injury Risk Functions (SAE, 2021)
- Biomechanical Responses of Small Female PMHS Subjected to Abdominal Loading (IRCOBI, 2022)
Lower Extremities
Recent field data studies have identified hip fractures in frontal crashes absent any femur fracture. The THOR 50th male dummy applied experimental research to develop new injury criteria based on hip or acetabular loading (add link to THOR content on site). In addition, data collection efforts are currently underway to examine the response of female specimens in knee-thigh-hip loading scenarios. These data will be used in the development of injury criteria for the THOR 5th dummy.
+ Resources and Reports
- The Tolerance of the Human Hip to Dynamic Knee Loading (Stapp Car Crash Journal, 2002)
- Comparison of Knee/Femur Force-Deflection Response of the THOR, Hybrid III, and Human Cadaver to Dynamic Frontal Impact Knee Loading (2003)
- Effects of Hip Posture on the Frontal Impact Tolerance of the Human Hip Joint (Stapp Car Crash Journal, 2003)
- Comparison of the Inertial Response of the THOR-NT, Hybrid III, and Unembalmed Cadaver to Simulated Knee-to-Knee-Bolster Impacts (ESV, 2005)
- Development of New Criteria for Assessing the Risk of Knee-Thigh-Hip Injury in Frontal Impacts Using Hybrid III Femur Force Measurements (ESV, 2009)
- Development of New Injury Risk Curves for the Knee/Distal Femur and the Hip for Use in Frontal Impact Testing (2009)
Injuries below the knee are common, especially in frontal crashes. These injuries can be costly and result in high incidence of long-term impairment and disability. NHTSA has supported a variety of research in this area that has, among other things, culminated in the development of the leg, foot and ankle of the THOR dummies and associated injury measures.
+ Resources and Reports
Female occupants experience a high prevalence of injuries to the leg, ankle and foot in frontal crashes. NHTSA has sponsored work looking specifically at the response of female subjects to axial loading through the heel, simulating the expected loading through the toe pan or pedals during a frontal crash. In addition, NHTSA research has studied other loading modes, such as dynamic dorsiflexion and inversion/eversion loading of the foot. These data will be used in the development of the THOR 5th dummy.
+ Resources and Reports
- Lower Leg Biofidelity Corridors for Heel Impact (NHTSA, 2019)
- Injury Risk Functions for 5th Percentile Females: Ankle Inversion and Eversion (IRCOBI, 2018)
- Biofidelity of THOR 5th Percentile Female ATD in Ankle Eversion and Inversion (SAE International Journal of Advances and Current Practices in Mobility, 2020)
While not a typical component of human response and ATD design or injury criteria, NHTSA has pursued research to better understand the frictional properties of skin to airbag interactions.
NHTSA is developing biomechanical corridors for skin/air bag friction by testing PMHS skin specimens on various air bag fabrics in vehicles.
+ Resources and Reports
- Experimental Investigation of Friction Between Vehicle Air Bag Material and Head Skin for Humans and Crash Test Dummies (International Mechanical Engineering Congress & Exposition, 2020)
Equity in Biomechanics Research
This section of NHTSA’s Biomechanics Research efforts focuses on populations that often are considered more vulnerable to injuries associated with motor vehicle crashes or that are not always well-represented by current test devices or testing protocols. A summary of NHTSA research efforts related to children, female crash safety, older occupants, obese occupants, motorcycle riders and pedestrians is provided.
Children
Female Crash Safety
Using sources including the Fatality Analysis Reporting System (FARS), the National Automotive Sampling System Crashworthiness Data System (NASS CDS), the Crash Investigation Sampling System (CISS), and the Crash Injury Research and Engineering Network (CIREN) databases, NHTSA conducts analysis to investigate motor vehicle injury and fatality incidence and risk. NHTSA recently updated the results of a 2013 study that compared relative fatality risk for females versus males. The update includes the most recent fatal crash data and found that the relative risk of fatality between females and males has been reduced, especially when considering newer vehicles. The increase in fatality risk for females relative to males for model year 2010-2020 vehicles was found to be 6.3 ± 5.4% and is significantly less than for model year 1960-2009 vehicles (18.3 ± 1.2%). For the latest generation of occupant protection systems (dual air bags, seat belt pretensioners and load limiters), the estimated female fatality risk relative to males was 5.8 ± 3.8%, which is statistically significantly lower than for belted occupants in vehicles without those additional occupant protections. A 2015 NHTSA study demonstrated that three-point seat belts and air bags were equally effective in reducing fatalities for both males and females.
NHTSA is conducting a detailed multi-variable modeling study to describe injury odds ratios for females versus males. The study is utilizing crash data from both NASS-CDS and CISS.
To better predict and prevent fatality and injury for females, NHTSA has focused on developing and evaluating advanced crash test dummies or anthropomorphic test devices (ATDs) that are more human-like than current dummies and have improved instrumentation and sensing capabilities.
THOR 5th Percentile Female ATD
NHTSA’s THOR 5th percentile advanced female dummy makes use of all available female-specific data for design (including size and shape), response and injury risk.
WorldSID-5th Female ATD
Neck: NHTSA is supporting research to collect female response data to assess the biofidelity of the THOR-05F neck. Additional experimental and modeling work may also be required to complete development of injury criteria and human-ATD transfer functions based on previously conducted THOR-05F tests in tension, compression, flexion, and extension.
Thorax: Thorax injuries remain prevalent in frontal crashes. NHTSA has conducted research on the structural characteristics of ribs based on sex and age. In addition, NHTSA has sponsored testing using small female post-mortem human subjects (PMHS) to study the injury tolerance of females in realistic, simulated crash conditions. The aim of this work is to inform development of tools, such as advanced female ATDs, that can be used to improve vehicle safety.
Abdomen: NHTSA is conducting research looking specifically at the response of female subjects to belt loading to the abdomen.
Knee/Thigh/Hip: NHTSA is currently collecting data to examine the response of female specimens in knee-thigh-hip loading scenarios. These data will be used in the development of injury criteria for the THOR 5th dummy.
Leg/Foot/Ankle: Females experience high prevalence of injuries to the leg, ankle and foot in frontal crashes. NHTSA has sponsored work looking specifically at the response of female subjects to axial loading through the heel, simulating the expected loading through the toe pan or pedals during a frontal crash.
Occupant Response in ADS-Equipped Vehicles: NHTSA is conducting research on human surrogate response in non-conventional seating configurations expected to be prevalent in vehicles with automated driving systems. This work includes a focus on small female occupants.
+ Experimental Data Reports
Injury Research Reports
- Characterization of Strain Mode in Human Ribs Subjected to Anterior-Posterior Loading (IRCOBI 2020)
- Thorax injury criteria considerations for the THOR 5th ATD (NHTSA Workshop on Human Subjects for Biomechanical Research, 2021)
- Injury Risk Functions for 5th Percentile Females: Ankle Inversion and Eversion (IRCOBI 2018)
To better understand how to predict and prevent fatality and injury for females, NHTSA supports development of finite element human body models (HBMs) and their use to study causes of injury. The human body models most commonly used by both NHTSA and industry tend to be the 50th percentile male and 5th percentile female, although a range of other sizes and shapes exist.
- 50th Percentile Female HBM - NHTSA is supporting the development of a 50th percentile female human body model, which will be used in parametric analyses to examine female injury risk. GHBMC 5th and 50th Percentile Female HBMs
Older Occupants
Pedestrians
Hardware
- Adult Headform
- 2D Drawing Package and Parts List
- Procedures for Assembly, Disassembly, and Inspection
- Child Headform
- 2D Drawing Package and Parts List
- Procedures for Assembly, Disassembly, and Inspection
- Upper Legform
- 2D Drawing Package and Parts List
- Procedures for Assembly, Disassembly, and Inspection
- FlexPLI Lower Legform
- 2D Drawing Package and Parts List
- Procedures for Assembly, Disassembly, and Inspection
- Qualification Procedures
Reports
- Overview Poster
- Test Procedure – Pedestrian Head Impact Against Central Hood (SAE 902315, Stapp Car Crash Conference, 1990)
- Summary of IHRA Pedestrian Safety WG Activities – Proposed Test Methods to Evaluate Pedestrian Protection Afforded by Passenger Cars (ESV, 2001)
- Pedestrian Head Impact Testing and PCDS Reconstructions (ESV, 2001)
- Assessment of an Advanced Pedestrian Dummy for Use in Full-Scale Case Reconstructions (DOT HS 809 391, 2002)
- A Demographic Analysis and Reconstruction of Selected Cases from the Pedestrian Crash Data Study (SAE, 2002)
- MADYMO Modeling of the IHRA Head-form Impactor (SAE, 2005)
- Component Leg Testing of Vehicle Front Structures (ESV, 2005)
- VRTC Pedestrian Research Activities (GTR No. 9 Informal Working Group)
- Pedestrian GTR Testing of Current Vehicles (ESV, 2007)
- Performance of Vehicle Bumper Systems with the EEVC/TRL Pedestrian Lower Legform (ESV, 2009)
- Assessment of the SIMon in Analyzing Head Injuries in Pedestrian Crashes (SAE, 2012)
- Pedestrian Injuries by Source: Serious and Disabling Injuries in US and European Cases (AAAM, 2012)
- Vehicle Hood Testing to Evaluate Pedestrian Headform Reproducibility, GTR No. 9 Test Procedural Issues, and U.S. Fleet Performance (NHTSA, 2008)
- Technical Evaluation of the Flexible Pedestrian Leg Impactor (NHTSA, 2008)
- Pop-Up Hood Pedestrian Protection (ESV, 2015)
- Analysis of Pedestrian Injuries by Passenger Vehicle Model Year (NHTSA, 2019)
- Technical Evaluation of the TRL Pedestrian Upper Legform (NHTSA, 2019)
- Pedestrian Protection: U.S. Vehicle Fleet Assessment (NHTSA, 2019)
- Relative Frequency of U.S. Pedestrian Injuries Associated with Risk Measured in Component-Level Pedestrian Tests (NHTSA, 2019)
- Assessment of Hood Designs for Pedestrian Head Protection: Active Hood Systems (NHTSA, 2020)
- Vehicle Bumper Performance in Part 581 vs. Pedestrian Leg Protection (NHTSA, 2020)
Presentations
- The Relationship Between Pedestrian Component Legform and Full Dummy Testing in Assessing Bumper Performance (SAE, 2006)
- NHTSA Pedestrian Testing with TRL and Flex-GTR Legforms and the Status of the GTR (SAE, 2010)
- NHTSA Evaluation of the Flex-GTR Legform on US Vehicles (SAE, 2012)
- Performance of Bumper Systems with Respect to Pedestrian Protection and Bumper Damageability Requirements (SAE, 2014)
- Real-World Pedestrian Crashes: Injury Trends and Fatality Risks (SAE, 2017)
- Overview of NHTSA Pedestrian Crashworthiness Research (SAE, 2018)
- Comparison of aPLI and FlexPLI-UBM Advanced Pedestrian Legforms (SAE, 2020)
Obese Occupants
Motorcycle Riders
ADS-Equipped-Vehicle Occupants
NHTSA is conducting research on occupant protection in non-conventional seating configurations expected to be prevalent in vehicles with automated driving systems, particularly forward- and rear-facing reclined seats. Topics in this section include human surrogate response data collection and analysis, assessment, and improvement of physical and computational surrogates, including anthropomorphic test devices (ATDs) and finite element human body models, and development and evaluation of occupant protection countermeasures.
Rear Impact
- Data: Test Results in NHTSA Biomechanics Database (Search for Contract/Study Title of ADS Rear-Facing Occupant Kinematics)
- Model: 2019 Honda Odyssey 2nd Row Seat FE Model
- Model: 3D Files for AV Buck & Seat as Configured in Sled Tests
- Biomechanical Responses and Injury Assessment of Post Mortem Human Subjects in Various Rear-facing Seating Configurations (Stapp Car Crash Conference, 2020)
- Biofidelity Evaluation of THOR-50M in Rear-Facing Seating Configurations Using an Updated BioRank System (SAE, 2022)
- Occupant Protection & Crashworthiness for ADS-Equipped Vehicles (SAE, 2021)
- UMTRI Workshop Presentation (2018)
- Head Trajectories of Post Mortem Human Surrogates in Moderate-Speed Rear Impacts (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2018)
- Biomechanical Responses and Injury Assessment of PMHS in Rear-facing Seating Configurations (SAE, 2019)
- Biomechanical Responses and Injuries of PMHS in Rear Facing Alternative Seating Configurations (SAE, 2020)
- Effects of Seatback Recline and Belt Restraint Type on PMHS Injuries in High-Speed, Rear-Facing Rigid Seat Tests (SAE, 2022)
Frontal Reclined
THOR-50M Modifications for Reclined Seating
Rear Seat
Anthropomorphic Test Devices
NHTSA's Anthropomorphic Test Devices (ATDs), or crash test dummies, are used extensively as part of regulation or consumer metric testing programs. They are also used to conduct research on issues relating to biomechanics, occupant protection, and vehicle crashworthiness. Included here on the NHTSA Biomechanics web page is information for advanced dummies, including the THOR dummies, that are currently being developed and/or evaluated by NHTSA.
Note: THOR® is a registered trademark.
- NHTSA Advanced Anthropomorphic Test Devices Development and Implementation Plan (This report is responsive to the Government Accountability Office recommendation in GAO-23-105595, 2024)
- Advanced Crash Test Dummies (PDF) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummies (MP4) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- The Process of Evaluation and Documentation of Crash Test Dummies for Part 572 of the Code of Federal Regulations (ESV, 2005)
THOR 50th Percentile Male ATD
Hardware
Public use disclosure and patent reference: These files are made available to the public without charge and may be used, copied, and distributed. Please note that portions of the shoulder design in these files are covered by U.S. Patent Nos. 9,514,659 and 9,799,234, assigned to Humanetics Innovative Solutions, Inc. (Humanetics) of Plymouth, Michigan, USA.
- 2D Drawing Package, August 2018 Draft (Adobe Acrobat)
- 2D Drawing Package, August 2018 Draft (AutoCAD)
- 3D Parametric Model, August 2018 Draft (Autodesk Inventor)
- 3D Parametric Model, August 2018 Draft (Generic STEP)
- Parts List, August 2018 Draft (Adobe Acrobat)
- Drawing Revisions, August 2016 to August 2018 (Adobe Acrobat)
Documentation
- Qualification Procedures Manual (Draft, September 2018)
- Qualification Specifications (Revisions, August 2016 to September 2018)
- Procedures for Assembly, Disassembly, and Inspection (Draft, August 2018)
- Durability Report (Draft, October 2019)
- Seating Procedure (Draft, June 2019)
- Injury Criteria for the THOR 50th Male ATD (September 2020)
- Repeatability and Reproducibility of Qualification Tests (Draft, 2021)
Papers and Reports
- Overview Poster
- Modifications to Improve the Durability, Usability and Biofidelity of the THOR-NT Dummy (ESV, 2011)
- Thoracic Biofidelity Assessment of the THOR Mod Kit ATD (ESV, 2013)
- Biofidelity Evaluation of the THOR and Hybrid III 50th Percentile Male Frontal Impact Anthropomorphic Test Devices (Stapp Car Crash Journal, 2017)
- Repeatability and Reproducibility of Oblique Moving Deformable Barrier Test Procedure (SAE, 2018)
- Comparison of the THOR-50M IR-TRACC Measurement Device to an Alternative S-Track Measurement Device (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2019)
Public Meetings
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- Advanced Crash Test Dummies - THOR-50M Update (MP4, begins at 1:35) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummies (PDF) (NHTSA Research Public Meeting, 2021)
THOR 5th Percentile Female ATD
Hardware
- Drawing Package (2019)
- 3-D CAD (2019)
Documentation
- Biomechanical Response Requirements
- Biofidelity Corridors | Link 1 | Link 2
- Biofidelity Report
Papers & Reports
- THOR 5th percentile female ATD design (ESV, 2017)
- Biofidelity evaluation of THOR 5thpercentile female ATD (IRCOBI, 2018)
Public Meetings
- Biofidelity Evaluation of THOR 5th Percentile Female ATD (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2017)
- Biofidelity of the THOR-05F ATD Abdomen in Fixed-Back Belt Pull Test Condition (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2018)
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- Status of NHTSA’s THOR-05F Evaluation (SAE, 2020)
- Biofidelity of THOR 5th Female in Frontal Sled Tests (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2020)
LODC 10-Year-Old Child ATD
Documentation
Papers and Reports
- Overview Poster
- Biomechanical Response of the Human Chin and Manubrium (2012)
- Dynamic Response Criteria for a Large Child ATD Thoracic Spine (IRCOBI, 2014)
- Comparative Biofidelity Assessment of the Large Omnidirectional Child Prototype and Hybrid III 10-Year-Old ATD (2014)
- The Large Omnidirectional Child (LODC) ATD: Biofidelity Comparison with the Hybrid III 10-Year-Old Stapp Car Crash Conference (2016)
- Abdominal Biofidelity Assessment of 50th Percentile Male and 10-Year-Old ATD Responses Relative to a Recently Developed Belt-Loading Corridor (IRCOBI, 2017)
- Cervical and Thoracic Spine Injury in Pediatric Motor Vehicle Crash Passengers (2019)
- Evaluation of the Large Omnidirectional Child (LODC) ATD (NHTSA, 2019)
- Development of a Multi-point Chest Deflection Measurement System for the Large Omnidirectional Child (LODC) Anthropomorphic Test Device ATD (2023)
- Development of a Dynamic Nonlinear Finite Element Model of the Large Omnidirectional Child Crash Test Dummy (2024)
Public Presentations
- Introduction of a New Thorax for a Large Child ATD (2014)
- Development of the Large Omnidirectional Child (LODC) ATD (SAE, 2016)
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- Development and Evaluation of a New Chest Deflection Measurement System for the LODC Child Dummy (SAE, 2020)
- Advanced Crash Test Dummies - LODC Update (MP4, begins at 13:55) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummies (PDF) (NHTSA Research Public Meeting, 2021)
WorldSID 50th Percentile Male ATD
Documentation
- Comparison of WorldSID and ES-2re Biofidelity Using an Updated Biofidelity Ranking System (ESV, 2009)
- WorldSID 50th Percentile Male Dummy Seating Procedure Evaluation and Revision (NHTSA, 2019)
- WorldSID 50th Percentile Male Durability Assessment (NHTSA, 2022)
- Evaluation of the WorldSID 50th Percentile Male Side Impact Dummy— Qualification and Sled Test Repeatability and Reproducibility (NHTSA, 2022)
- WorldSID-50M Qualification Procedures (2024)
- WorldSID-50M Procedures for Assembly, Disassembly, and Inspection PADI (2024)
- WorldSID-50M Repeatability and Reproducibility of Qualification Tests (2024)
Papers & Reports
- Real World Older Occupant Crash Data and Sensitivity Of THOR-NT and WorldSID Dummy Thoraces (ESV, 2011)
- Male and Female WorldSID and Post Mortem Human Subject Responses in Full-Scale Vehicle Tests (Traffic Injury Prevention, 2017)
- WorldSID ATD Family Overview Poster (NHTSA, 2019)
- Determination of Optimal RibEye LED Locations in the WorldSID 50th Percentile Male Dummy (NHTSA, 2019)
Public Presentations
- Biofidelity Analysis of WorldSID and ES-2re (Hyundai/NHTSA Research Sharing Meeting, 2009)
- Evaluation of the RibEye Multipoint Deflection Measurement System installed in the WorldSID-50M Dummy (SAE Government Industry Meeting, 2017)
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- Advanced Crash Test Dummies - WorldSID-50M Update (MP4, begins at 27:10) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummies - RibEye Evaluation in WorldSID-50M (MP4, begins at 35:39) (NHTSA Research Public Meeting, 2021)
- Advanced Crash Test Dummies (PDF) (NHTSA Research Public Meeting, 2021)
WorldSID 5th Percentile Female ATD
Papers and Reports
- Male and Female WorldSID and Post Mortem Human Subject Responses in Full-Scale Vehicle Tests (Traffic Injury Prevention, 2017)
- WorldSID ATD Family Overview Poster (NHTSA, 2019)
Public Presentations
- Advanced Crash Test Dummy Research (NHTSA Research Public Meeting, 2019)
- Biofidelity Evaluation of WorldSID-05F with Mod Kit and SID-IIs BLD (SAE Government Industry Meeting, 2022)
BIORID-II 50th Percentile Male ATD
Math Modeling
Computer modeling of human tissue could be traced back to the 1950s. However, the knowledge of material characteristics and tolerance of human tissue necessary to build and utilize high fidelity human models was lacking up until recently. Stable mathematical codes capable of simulating high energy impacts, such as those occurring in car crashes, also experienced major advances in recent years allowing for simulation of not only the complex kinematics of the human body during the crash event, but also predict the onset and severity of potential injury.
NHTSA research in the area of math modeling includes the development, evaluation and application of finite element human body models (HBMs), ATD models, as well as the development and application of machine learning-based models.
- Overview Poster
- Virtual Testing & Computational Biomechanics Session (NHTSA Safety Research Portfolio Public Meeting: Fall 2022)
Human Body Models
ATD Models
Machine Learning
This project involves using supervised deep learning to predict head kinematics from crash videos to predict brain injury risks. To prove the concept, a supervised deep learning model was developed to predict head angular velocity time histories using FE crash simulation videos. The deep learning model showed good time history prediction capabilities. To extend the concept to physical crash tests with ATDs, the ATD head needs to be tracked during the crash event. For that purpose, a deep learning-based head detection model to detect and track the ATD head in crash videos was developed. A pretrained “You Only Look Once” or YOLO v4 object detection model was used, and transfer learning was performed to develop the ATD head detection model. The model was evaluated on NHTSA crash test videos and showed good results in detecting the ATD head. Going forward, this head detection model will help generate training data that will be used for developing deep learning models for predicting ATD head kinematics.
This study involves using supervised deep learning to predict crash parameters like principal direction of force (PDOF) and change in velocity (delta-V) from vehicle crash images. PDOF and Delta-V are the two most important parameters that affect injury outcome in vehicular crashes. These crash parameters are currently computed using software like WinSmash. In NASS-CDS and CISS, these crash parameters are frequently not documented. The goal is to develop a deep learning model that uses crash images from NASS-CDS, CISS to predict PDOF and delta-V. Such a model can then be used to find Delta-V and PDOF for CISS cases with missing information and also such a model can be extended further to predict injuries based on predicted Delta-V and PDOF, which can help the first responders.
A recent finite element-based study by NHTSA found geometric differences between human body model thoraces to be a significant contributing factor in predicting differences between female and male thoracic injury risk. The goal of this study is to use supervised and unsupervised deep learning methods on computed tomography (CT) data obtained from NHTSA’s CIREN database to better understand the geometric differences between male and female skeletal thoraces. This research will aid in assessments of current GHBMC FE models and guide their future development.
Advanced Automatic Collision Notification
Advanced Automatic Collision Notification (AACN) is a system that provides immediate notification of a motor vehicle crash, along with an estimate of the likelihood of severe injury based on vehicular data (e.g., Delta-V). This system can improve the speed and accuracy of dispatch for motor vehicle crashes and can also help get the right patient to the right hospital by assisting EMS providers in determining which patients need the resources of a trauma center. Quickly routing and evaluating AACN crash data can potentially decrease time to definitive treatment and improve crash victims’ chances of survival, while improving the efficiency of EMS and trauma systems as a whole and conserving costs while increasing public safety.
Dummy Management Laboratory
Within NHTSA’s Vehicle Research and Test Center (VRTC) resides the Dummy Management Laboratory (DML). The DML manages and maintains about 500 dummies, 6,000 sensors, and 26,000 spare parts for the offices of NCAP, Compliance, and Research. The DML inspects, repairs, and prepares dummies to support all dummy needs across the agency. To ensure that these needs are met, dummies are configured and delivered to test laboratories across the country in support of NHTSA contracts. Due to the wide breadth of programs that the DML supports, it is uniquely positioned to provide a high level of expertise while troubleshooting and diagnosing various dummy-related issues for the agency.
Experimental Data and Analysis Tools
The NHTSA Biomechanics Test Database is a repository of primarily data collected from NHTSA-supported experimental biomechanics research. The experiments often produce human response and injury data appropriate for use in the development and assessment of virtual and physical testing tools such as human body models and anthropomorphic test devices. The data is used by academia, the automotive industry, and others to improve the safety of automobiles and reduce death and injuries on our nation’s highways. Because of the nature of the testing, the applicability of the data extends far beyond auto safety, and may be useful for those in sports medicine, space travel, aircraft travel, the military or any activity where the human body is exposed to impact.
Resources and Reports
NHTSA developed an objective, quantitative method for assessing biofidelity among ATDs.
Resources and Reports
- Development of a New Biofidelity Ranking System for Anthropomorphic Test Devices (Stapp Car Crash Journal, 2002)
- Comparison of WorldSID and ES-2re Biofidelity Using an Updated Biofidelity Ranking System (ESV, 2009)
- Optimized Phasing of PMHS Response Curves for Biofidelity Targets (IRCOBI, 2012)
- A Methodology for Generating Objective Targets for Quantitatively Assessing the Biofidelity of Crash Test Dummies (ESV, 2013)
- A Methodology for Creating PMHS Targets with a Two-Dimensional Standard Deviation Ellipse Tolerance for Quantitatively Assessing Dummy Biofidelity (IRCOBI, 2013)
- Improvements to NHTSAs Biofidelity Ranking System and Application to the Evaluation of the THOR 5th Female Dummy (IRCOBI, 2018)
- Biofidelity Evaluation of THOR-50M in Rear-Facing Seating Configurations Using an Updated BioRank System (SAE, 2022)
- An Improved Normalization Methodology for Developing Mean Human Response Curves (NHTSA International Workshop on Human Subjects for Biomechanical Research, 2008)
- An Improved Normalization Methodology for Developing Mean Human Response Curves (ESV, 2013)
- A Deformation Energy Approach to Normalizing PMHS Response Data and Developing Biofidelity Targets for Dummy Design (IRCOBI, 2014)
- An Improved Deflection Energy Method to Normalise PMHS Thoracic Response Data (IRCOBI, 2017)
Public Meetings
Since 1973, NHTSA has sponsored a workshop on human subjects in biomechanical research. The workshop is intended as an informal forum for the exchange of ideas and presentation of preliminary results on injury research focused on experiments involving human volunteers or surrogates. The workshop features presentations on crash field data analysis, testing of human volunteers and surrogates, tissue testing, computational modeling, and dummy development, instrumentation, and testing.
Since 2007, NHTSA has co-sponsored the Injury Biomechanics Symposium held at The Ohio State University. The Symposium is intended to stimulate and reward strong injury biomechanics research among students and recent graduates. Studies of interest include those that quantify human injury tolerance, develop analytical or experimental tools that assess injury risk, or evaluate the effectiveness of safety countermeasures in environments such as automotive crashes, sports injuries or military trauma.