Research                                  

# Biomechanics

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# 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.

#                  Topic Areas            

                        -  Field and Crash Data 
                        -  Human Response and Injury Research 
                        -  Equity in Biomechanics Research 
                        -  ADS-Equipped-Vehicle Occupants 
                        -  Anthropomorphic Test Devices 
                        -  Math Modeling 
                        -  Advanced Automatic Collision Notification 
                        -  Dummy Management Laboratory 
                        -  Experimental Data and Analysis Tools 
                        -  Public Meetings 

# 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

The Crash Injury Research and Engineering Network (CIREN) is one such effort. CIREN is a collaborative effort between NHTSA Human Injury Research, NHTSA National Center for Statistics and Analysis (NCSA), trauma physicians, and experts in the fields of impact biomechanics and mechanical engineering. CIREN collects and publishes detailed data on crashes resulting in serious or disabling injury.

####                     Resources & Reports                    **

                        - CIREN
                        - CIREN Overview Poster

# 
Future of Crash Safety

In addition to the collection and use of retrospective, real-world data, NHTSA has developed modeling techniques to project future estimates of crash frequency and outcomes by modeling the forecasted effects of transportation trends, safety initiatives, and new technology.

####                     Resources & Reports                    **

                        - 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

              - NHTSA Crash Viewer
              - NCSA Crash Data Systems

# 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

Injuries to the skull, face and brain are prevalent and often result in life-threatening outcomes from motor vehicle crashes. NHTSA research in this area is focusing on development and application of injury criteria.

####                     Traumatic Brain Injury                    **

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)

####                     Subdural Hematoma                    **

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)

####                     Kinematics                    **

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

Injuries to the cervical, thoracic and lumbar spine are prevalent and often life-threatening outcomes from motor vehicle crashes. NHTSA research in this area is focusing on biofidelity and injury response experiments to support physical (ATDs) and virtual (human body models) test tool evaluation and injury criteria development.

####                     Cervical 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**
                        - On the Importance of the Forces and Moments at the Occipital Condyles in Predicting Ligamentous Cervical Spine Injuries  (IRCOBI, 2017)

####                     Cervicothoracic Biomechanics                    **

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                    **

#### 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

The shoulder can be an important load path from occupant to vehicle contacts in motor vehicle crashes. NHTSA has conducted research to develop response requirements and determine injury tolerance for conditions, such as side impacts, that involve significant loading of the shoulder.

####                     Lateral and Oblique Response and Injury Tolerance                    **

#### 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)

####                     Pediatric Shoulder Stiffness                    **

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**
                        - Characterization of the Pediatric Shoulder’s Resistance to Lateral Loading Conditions  (ESV, 2011)

# 
Thorax

Thorax injuries remain a prevalent outcome from motor vehicle crashes. NHTSA research in this area largely is focusing on biofidelity and injury response experiments to support physical (ATDs) and virtual (human body models) test tool evaluation and injury criteria development.

####                     Small Female Thoracic Injury Research                    **

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)

####                     Oblique vs. Lateral Response and Injury Tolerance                    **

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)

####                     Thorax Response Data Processing                    **

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)

####                     Rib Structural Characteristics, Dynamic Bending Response, and Thoracic Hierarchy                    **

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

As with other body regions, the abdomen has unique response and injury characteristics associated with motor vehicle crashes. NHTSA research in this area largely is focusing on biofidelity and injury response experiments to support ATD evaluation and injury criteria development.

####                     Abdomen Response and Pressure-Based Abdomen Injury Risk                    **

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

Crash-induced injuries to the lower extremities, while not usually a serious threat to life, often result in long-term disability with substantial economic costs. These injuries still occur frequently in frontal crashes, regardless of occupant restraint condition.

####                     Knee-Thigh-Hip                    **

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)

####                     Leg/Foot/Ankle                    **

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**
                        - Posterior Cruciate Ligament Response to Proximal Tibia Impact  (SAE, 2019)

####                     Small Female Leg/Foot/Ankle Injury Research                    **

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)

####                     Skin                    **

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.

####                     Skin/Air Bag Frictional Characteristics                    **

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

NHTSA has supported research largely targeting the design and development of new advanced child crash test dummies. Please refer to the ATD section for more details.

# 
Female Crash Safety

Safety is the top priority for the U.S. Department of Transportation and NHTSA. As equity is also a priority, NHTSA is working to address sex inequalities in crash safety outcomes. Although more male motor vehicle occupants are killed in motor vehicle crashes than females, recent studies suggest that female occupants have higher injury and fatality risk than males in comparable motor vehicle crashes. NHTSA has published a Female Crash Safety Research Plan that summarizes active and planned research that NHTSA is undertaking in this area.
                  - NHTSA Female Crash Safety Research Plan  (2022)

####                     Field Data Analysis                    **

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.

####                     Advanced Dummies                    **

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.
                        - THOR 5th Overview
                        - THOR 5th Finite Element Model (Version 2.0)

**WorldSID-5th Female ATD**
                        - WorldSID-5th Overview

####                     Female Response and Injury Experimental Data                    **

*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)

####                     Human Body Modeling                    **

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

Older occupants may sustain more severe injuries from motor vehicle crashes due to weaker bones and calcified tissues. Injuries to the head and thorax are among the most frequently injured body regions for older occupants. Head and thorax injuries can also be life-threatening, especially for older occupants, as their risk of death given a certain injury generally increases with age. Many of the injury criteria we develop and employ on crash test dummies include age as a covariate. However, those injury criteria only include risk of injury, which is sufficient for a younger occupant. But an older occupant may have an increased risk of death given that they have sustained a certain injury. So, injury criteria for older occupants may need to include some adjustment to account for their increased risk of death. In addition, most of the existing research on human thoracic injury tolerance has been performed on subjects with “healthy” bones. As bone health typically degrades with age, in order to get a more accurate picture of injury tolerance for very old occupants, subjects with osteopenia or osteoporosis need to be tested. NHTSA is currently collaborating with Elderly Side Impact, a consortium of industry and university members, to develop a thoracic injury risk curve for older occupants with “unhealthy” bones in side impact. Other current NHTSA research on older occupants includes efforts toward development of a subdural hematoma injury risk curve by age and first steps toward development of potential crash test parameters that would improve thoracic safety for older occupants. Information on research related to older occupant thorax injury can be found below.

####                     Resources & Reports                    **

                        - Real World Older Occupant Crash Data and Sensitivity of THOR-NT and WorldSID Dummy Thoraces  (ESV, 2011)
                        - Injury Risk Estimates: A Method for Determining Equivalent Increase in Risk of Death for Older and Younger Occupants  (IRCOBI, 2013)

# 
Pedestrians

Pedestrians represent a large proportion of injured road users in vehicle crashes. The head and lower extremities are the most frequently injured body regions. To address these injuries, for many years, NHTSA has conducted pedestrian research in three areas: (1) test tool & procedure development, (2) injury data analysis, and (3) vehicle testing & evaluation.

####                     Resources & Reports                    **

**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

Obesity has been shown to affect injury risk in crashes. NHTSA has supported research looking at belt fit/routing and possible effects on injury risk as well as submarining in frontal crashes. Additionally, NHTSA has supported research looking at anthropometry/shape of different body mass index (BMI) occupants for purposes of developing finite element human models for normal versus obese occupants.

# 
Motorcycle Riders

A large proportion of serious injuries in US motorcycle crashes are head injuries, even among helmeted riders. Around the world, several motorcycle helmet testing standards exist, each with their own test procedures and performance requirements, primarily for the evaluation of protection in linear impacts. Many additional procedures have been reported in the literature for evaluation of performance in rotational loading. A general knowledge of the procedures and requirements of the various standards and test methods is key to understanding the effectiveness of motorcycle helmets. Head injury risks can generally be classified as placing limits on either: (a) translational acceleration or (b) rotational properties (acceleration or velocity). It may be important to evaluate helmet performance relative to both translational and rotational loading. However, there is no consensus among standards and tests reported in the technical literature as to which methods or test procedures are effective in evaluating helmet protection in impacts involving rotation. NHTSA is currently evaluating various test procedures including both translational and rotational loading.

####                     Research & Reports                    **

                        - Head Injuries to Helmeted and Unhelmeted Motorcyclists in US Trauma Data , IRCOBI 2013

# 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.

####                     Resources & Reports                    **

                        - Overview Poster
                        - NHTSA Research Public Meeting  (2019)
                        - NHTSA Research Public Meeting  (2021)

# 
Rear Impact

#### Biomechanics in ADS-Equipped Vehicle Seating Scenarios

NHTSA is supporting research to collect data on human surrogate response in rear-facing reclined seats. The goals of this project are to (1) generate biomechanical corridor data from human surrogates in both upright or reclined seats in low and high-speed rear impacts and (2) compare ATDs and human body model responses to that biomechanical data.

####                     Resources & Reports                    **

                        - 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

#### ADS-Equipped Vehicle Occupant Kinematics

NHTSA is supporting research to collect data on human surrogate response in forward-facing reclined seats. Data collection is focusing on 50th percentile male occupants and vulnerable populations including small female occupants and obese occupants.

####                     Resources & Reports                    **

                        - Task Implementation Plans                           - Phase I: 50th Percentile Male  (UMTRI)
                          - Phase II: Small female and obese occupants  (MCW) 
                        - Test Results in NHTSA Biomechanics Database (Search for Contract/Study Title of “AUTOMATED VEHICLE OCCUPANT KINEMATICS”)
                        - Initial Observations of Human Surrogate Response in Forward-facing Reclined Seats  (SAE, 2021)

# 
THOR-50M Modifications for Reclined Seating

NHTSA is supporting efforts to design, develop, fabricate, and install modifications to the THOR-50M ATD to allow use in crash tests involving reclined seating configurations. This project was developed based on the findings of a NHTSA study which identified several limitations in the use of the THOR-50M ATD in reclined seating configurations.

####                     Resources & Reports                    **

                        - ATD Seating in Highly Reclined Seats  (SAE, 2019)
                        - THOR-50M Modification for Reclined Seating – Initial Assessment Report
                        - Modifications to the THOR-50M for Improved Usability in Reclined Postures – Update and Preliminary Findings  (SAE, 2021)

# 
Rear Seat

In ADS-equipped vehicles, when no human driver is present, it is hypothesized that occupants may self-select a rear-seat location, particularly in a rideshare environment, which could lead to higher rear seat occupancy rates than today. NHTSA is conducting research to assess the occupant protection performance in rear seats with a variety of vehicle designs characteristics and identify characteristics likely to improve safety.

####                     Resources & Reports                    **

Hybrid III and THOR 50M Responses in the Rear Seat During Frontal Crash Sled Tests (SAE, 2020)

# 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.*

####                     Resources & Reports                    **

                        - 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

The THOR 50th percentile male is an advanced anthropomorphic test device (ATD or crash test dummy) that represents human-like anthropometry and response to impact. The THOR 50th male includes extensive instrumentation to assess the performance of vehicle safety systems designed to mitigate injuries in frontal and frontal oblique crashes.

####                     Resources & Reports                    **

**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

The THOR 5th ATD builds on the technology of the THOR 50th Male ATD but is designed to represent a 5th percentile female automotive occupant. The THOR 5th is a frontal crash ATD that has been designed using female-specific response and injury data and is intended for use in the front and rear vehicle seats during crash tests. It has improved injury prediction capabilities when compared to the current small female frontal crash dummy (Hybrid III 5th) due to additional upgraded sensors in the head, thorax, abdomen, and legs. The THOR 5th has significantly improved biofidelity over the Hybrid III 5th female ATD. NHTSA is currently supporting efforts to make design/durability improvements of the ATD and complete the required technical documentation including an injury criteria report for the THOR 5th, assembly/disassembly instructions, and a qualification manual.

####                     Resources & Reports                    **

**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

NHTSA is developing this ATD to represent children in the 8- to 12-year-old age range. This project was prompted by limitations with head and abdomen injury assessment capability observed with the Hybrid III 10-year-old ATD. The LODC’s design leverages pediatric biomechanical data generated over the past 15 years and has been shown to be a more biofidelic alternative to the Hybrid III. The features that set it apart, aside from components that better reflect pediatric response/anthropometry, are a flexible thoracic spine, instrumented abdomen, and laser-based thorax deflection measurement. The LODC is being developed completely in-house, which will allow NHTSA to provide the full details (three-dimensional soft part specifications, material composition, tooling, temperature/curing for molding parts, etc.) required for a repeatable dummy to be manufactured.

 

####                     Resources & Reports                    **

**Documentation**
                        - Abdominal and Thoracic Injury Risk Functions for the Large Omni-directional Child (LODC) ATD

**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)

**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

The WorldSID 50th percentile male side impact dummy is an advanced anthropomorphic test device (ATD or crash test dummy) that represents human-like anthropometry and response to impact. The dummy includes extensive instrumentation to assess the performance of vehicle safety systems designed to mitigate injuries in side impact crashes. Initially developed under the auspices of the International Organization of Standardization (ISO), the dummy is intended for worldwide use in research, development, and regulation of side impact crashes.

 

####                     Resources & Reports                    **

**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)

**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

The WorldSID 5th percentile female side impact dummy is primarily based on the technology used in the WorldSID 50th percentile male dummy but represents a small female occupant. The NHTSA biofidelity evaluation of the WorldSID 5th ATD indicated that improved biofidelity was needed, especially in the thorax. These biofidelity improvements are in progress. Once acceptable biofidelity is established, the ATD evaluation will continue, including durability, repeatability and reproducibility, RibEye evaluation in the ATD, and corresponding documentation.

####                     Resources & Reports                    **

**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

The BIORID-II 50th percentile male rear impact dummy is an advanced anthropomorphic test device (ATD or crash test dummy) that represents human-like anthropometry and response to impact. The dummy includes extensive instrumentation and a fully articulated spine to assess the performance of vehicle seat backs and head restraints designed to mitigate whiplash injuries in low-speed rear impact crashes. The dummy is intended for worldwide use in research, development, and regulation of vehicle seat backs and head restraints.

**Public Presentations**
                  - Advanced Crash Test Dummy Research  (NHTSA Research Public Meeting, 2019)

# 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

NHTSA has supported the development, evaluation and application of human body models that include children and adult (male and female) occupant and pedestrian models. NHTSA is the leading sponsor of GHBMC, Global Human Body Models Consortium.

GHBMC is a consortium of seven auto makers and one supplier created to consolidate individual research and development activities in human body modeling into a single global effort to advance crash safety technology.

NHTSA has used human body models for various studies, which have included parameter studies of airbag/seatbelt designs for reducing head rotational velocities in frontal crashes, assessments for the need to continue use of a combined force and moment formula for neck injury prediction, as well as a significant number of studies evaluating female versus male injury risk (add link to Female Crash Safety Section).

NHTSA also developed the SIMon model for brain injury prediction.

# 
ATD Models

NHTSA has supported the development of finite element models of various anthropomorphic test devices (ATDs) such as the THOR 50th male and THOR 5th female.

# 
Machine Learning

Machine learning is a branch of artificial intelligence that involves the development of algorithms that can analyze input and output data, learn from it and make predictions. Deep learning is a subset of machine learning where multi-layered artificial neural networks learn from input and output data in developing an algorithm or model for a given purpose. NHTSA is applying deep learning methods coupled with data in the form of images/videos from real-world crashes, crash tests, crash simulations and/or medical imaging to address various research questions.

####                     Head Kinematics from Crash Videos                    **

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.
                        - Deep learning methodology for predicting time history of head angular kinematics from simulated crash videos  (NHTSA, 2022).

####                     Delta V and PDOF from Crash Images                    **

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. 

####                     Medical Imaging Analysis – Geometric Differences Between Male and Female Thoraces                    **

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.

####                     Resources & Reports                    **

                        - Advanced Automatic Collision Research Report  (NHTSA, 2019)
                        - Predicting Severe Injury in Motor Vehicle Crashes  (ESV, 2017)
                        - Estimate of Mortality Reduction with Implementation of Advanced Automatic Collision Notification  (ESV, 2017)

# 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

####                     Biomechanics Test Database                    **

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 Biomechanics Test Database

####                     Biofidelity Ranking System                    **

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

####                     NHTSA International Workshop on Human Subjects for Biomechanical Research                    **

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.

####                     Injury Biomechanics Symposium                    **

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.