61896 Federal Register / Vol. 88, No. 172 / Thursday, September 7, 2023 / Proposed Rules 

DEPARTMENT OF TRANSPORTATION 

National Highway Traffic Safety 

Administration 

49 CFR Part 572 

[Docket No. NHTSA–2023–0031] 

RIN 2127–AM20 

Anthropomorphic Test Devices; THOR 

50th Percentile Adult Male Test 

Dummy; Incorporation by Reference 

AGENCY: National Highway Traffic 

Safety Administration (NHTSA), 

Department of Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: This document proposes to 

amend NHTSA’s regulations to include 

an advanced crash test dummy, the Test 

Device for Human Occupant Restraint 

(THOR) 50th percentile adult male 

(THOR–50M). The dummy represents 

an adult male of roughly average height 

and weight and is designed for use in 

frontal crash tests. NHTSA plans to 

issue a separate NPRM to amend 

Federal Motor Vehicle Safety Standard 

(FMVSS) No. 208, ‘‘Occupant crash 

protection,’’ to specify the THOR–50M 

as an alternative (at the vehicle 

manufacturer’s option) to the 50th 

percentile adult male dummy currently 

specified in FMVSS No. 208 for use in 

frontal crash compliance tests. 

DATES: You should submit your 

comments early enough to be received 

not later than November 6, 2023. 

Proposed Effective Date: Since this 

rulemaking action would not impose 

requirements on anyone, we are 

proposing that the final rule would be 

effective on publication in the Federal 

Register. 

ADDRESSES: You may submit comments 

electronically to the docket identified in 

the heading of this document by visiting 

the Federal eRulemaking Portal at 

http://www.regulations.gov. Follow the 

online instructions for submitting 

comments. 

Alternatively, you can file comments 

using the following methods: 

• Mail: Docket Management Facility: 

U.S. Department of Transportation, 1200 

New Jersey Avenue SE, West Building 

Ground Floor, Room W12–140, 

Washington, DC 20590–0001. 

• Hand Delivery or Courier: West 

Building Ground Floor, Room W12–140, 

1200 New Jersey Avenue SE, between 9 

a.m. and 5 p.m. ET, Monday through 

Friday, except Federal holidays. To be 

sure someone is there to help you, 

please call (202) 366–9826 before 

coming. 

• Fax: (202) 493–2251. 

Instructions: All submissions must 

include the agency name and docket 

number or Regulatory Information 

Number (RIN) for this rulemaking. For 

detailed instructions on submitting 

comments and additional information 

on the rulemaking process, see the 

Public Participation heading of the 

Supplementary Information section of 

this document. Note that all comments 

received will be posted without change 

to http://www.regulations.gov, including 

any personal information provided. 

Please see the Privacy Act heading 

below. 

Docket: For access to the docket to 

read background documents or 

comments received, go to http://

www.regulations.gov. You may also 

access the docket at 1200 New Jersey 

Avenue SE, West Building, Room W12– 

140, Washington, DC 20590, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal Holidays. 

Telephone: 202–366–9826. 

Confidential Business Information: If 

you claim that any of the information in 

your comment (including any additional 

documents or attachments) constitutes 

confidential business information 

within the meaning of 5 U.S.C. 552(b)(4) 

or is protected from disclosure pursuant 

to 18 U.S.C. 1905, please see the 

detailed instructions given under the 

Public Participation heading of the 

Supplementary Information section of 

this document. 

Privacy Act: Please see the Privacy 

Act heading under the Regulatory 

Analyses section of this document. 

FOR FURTHER INFORMATION CONTACT: For 

non-legal issues, you may contact Mr. 

Garry Brock, Office of Crashworthiness 

Standards, Telephone: (202) 366–1740; 

Email: Garry.Brock@dot.gov; Facsimile: 

(202) 493–2739. For legal issues, you 

may contact Mr. John Piazza, Office of 

Chief Counsel, Telephone: (202) 366– 

2992; Email: John.Piazza@dot.gov; 

Facsimile: (202) 366–3820. The address 

of these officials is: the National 

Highway Traffic Safety Administration, 

1200 New Jersey Avenue SE, 

Washington, DC 20590. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Executive Summary 

II. Background 

III. Design, Construction, and 

Instrumentation 

A. Anthropometry 

B. Technical Data Package 

C. Head and Face 

D. Neck 

E. Chest 

1. Design 

2. Instrumentation 

F. Shoulder 

1. Alternate Shoulder Specification 

2. Shoulder Slip 

G. Hands 

H. Spine 

I. Abdomen 

J. Pelvis 

K. Upper Leg 

L. Knee 

M. Lower Leg 

N. Data Acquisition System 

IV. Biofidelity 

V. Qualification Tests 

A. Head Impact 

B. Face Impact 

C. Neck 

D. Upper Thorax 

E. Lower Thorax 

F. Abdomen 

G. Upper Leg 

H. Knee and Lower Leg 

VI. Repeatability and Reproducibility 

A. Qualification Tests 

B. Sled Tests 

1. Methodology 

2. Thoracic Injury Criteria Development 

Sled Tests 

3. Low-Speed Belted Sled Tests 

4. Low-Speed Unbelted Sled Tests 

VII. Overall Usability and Performance 

A. Assembly and Qualification 

B. Durability and Maintenance 

1. Elevated Energy Qualification Test 

Series 

2. Oblique OMDB Test Series 

3. FMVSS No. 208 Unbelted Vehicle Crash 

Tests 

C. Sensitivity to Restraint System 

Performance 

VIII. Intellectual Property 

IX. Consideration of Alternatives 

X. Lead Time 

XI. Incorporation by Reference 

XII. Regulatory Analyses 

XIII. Public Participation 

Proposed Regulatory Text 

I. Executive Summary 

This document proposes to amend 

NHTSA’s regulation on 

anthropomorphic test devices—or, more 

colloquially, crash test dummies—to 

include an advanced crash test dummy, 

the Test Device for Human Occupant 

Restraint (THOR) 50th percentile adult 

male (THOR–50M). The dummy 

represents an adult male of roughly 

average height and weight and is 

designed for use in frontal crash tests. 

Crash test dummies are complex 

instruments that simulate the response 

of a human occupant in a crash. Each 

type of test dummy is designed for use 

in specific types of crashes (for instance, 

frontal or side) and is instrumented with 

sensors to measure the forces that would 

have been experienced by a human 

occupant in a similar crash in the real 

world. These measurements are then 

used to assess the potential for injury. 

Crash test dummies are used by 

NHTSA and by the broader vehicle 

safety community in a variety of ways. 


ddrumheller on DSK120RN23PROD with PROPOSALS4
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1This reflects a ‘‘bookend’’ approach to testing 

vehicles for crashworthiness, in which a range of 

occupant types, bookended by an average male and 

a small-stature female, is tested. NHTSA is 

currently supporting research to assess the possible 

benefits of developing new crash test dummies, 

such as a 50th percentile female crash test dummy. 

2NHTSA has registered the term ‘‘THOR’’ as a 

trademark (U.S. Registration No. 5,104,395). 

3The HIII–50M is also specified for use in FMVSS 

No. 202a, Head Restraints, in an optional rear 

impact dynamic test. 

4FMVSS No. 208 THOR–50M Compliance Option 

(RIN 2127–AM21), Spring 2023 Unified Agenda of 

Regulatory and Deregulatory Actions; Department 

of Transportation, available at https://

www.reginfo.gov/public/do/eAgendaViewRule?

pubId=202304&RIN=2127-AM21. 

5NHTSA also uses ATDs in sled tests (which 

simulate a vehicle crash by using a simplified test 

buck to represent a vehicle), and out-of-position air 

bag tests. ATDs are also used outside the vehicle 

safety context to measure human responses in a 

variety of other areas, such as aviation and 

aeronautics. 

NHTSA uses crash test dummies to test 

vehicles for compliance with Federal 

Motor Vehicle Safety Standards 

(FMVSSs) and to determine vehicle 

crashworthiness ratings for the New Car 

Assessment Program’s (NCAP) 5-Star 

Safety Ratings, as well as to conduct 

vehicle safety research. Crash test 

dummies are also used by regulatory 

authorities in other countries and 

regions, third-party vehicle rating 

programs, motor vehicle and equipment 

manufacturers, and others to evaluate 

vehicle safety and design safer vehicles 

and equipment. 

The dummies NHTSA currently uses 

in FMVSS compliance testing and 

NCAP are documented in 49 CFR part 

572, Anthropomorphic Test Devices. 

Part 572 sets out detailed design 

information, including engineering 

drawings and procedures for assembly 

and inspection. These are intended to 

describe the dummy with sufficient 

detail so that it is an objective 

measuring tool that produces consistent 

responses. NHTSA has codified 

numerous dummies that range in sex, 

size, age, and measurement capability. 

This includes dummies representing 

midsize adult males, small-stature adult 

females, infants, toddlers, and older 

children.1 These dummies are meant to 

provide a range of body types in order 

to maximize data and test results that 

can assess injury and fatality risks in a 

range of crash outcomes. The 50th 

percentile male dummy currently 

defined in Part 572 for frontal impacts 

is the Hybrid III–50M, which NHTSA 

uses to test for compliance with the 

frontal crash test requirements in 

FMVSS No. 208, ‘‘Occupant crash 

protection’’ and to rate vehicles for 

NCAP. NHTSA added the HIII–50M to 

Part 572 in 1986. 

NHTSA is continually researching 

and improving its test dummies and has 

been researching advanced test 

dummies since the implementation of 

the HIII–50M. An initial THOR–50M 

design was published in 2001. There are 

currently two different THOR dummies, 

the THOR–50M, and one under 

development that represents a smallstatured adult female, the THOR 5th 

percentile adult female (THOR–05F). 

Although this proposal is limited to the 

THOR–50M, we anticipate publishing a 

rulemaking proposal in the near future 

to add the THOR–05F to Part 572. 

The THOR–50M improves on the 

HIII–50M in a number of ways. It 

responds more like a human occupant 

in a crash and its advanced 

instrumentation enables it to more 

accurately measure the forces acting on 

the dummy. As a result, it is better able 

to predict the risk of injury to a human 

occupant. This should help vehicle 

designers develop and test improved 

occupant restraint systems (e.g., 

advanced seat belts and air bags) as well 

as the types of novel vehicle seating 

configurations likely to be used in 

highly automated vehicles. 

NHTSA has tentatively concluded 

that the THOR–50M is sufficiently 

biofidelic, exhibits repeatable and 

reproducible performance, and is 

sufficiently durable. As such, we believe 

that it would be suitable for use in 

regulatory compliance testing and is 

therefore suitable for incorporation into 

Part 572. NHTSA and others have 

already taken advantage of the THOR– 

50M’s advanced capabilities. NHTSA, 

vehicle and restraint manufacturers, and 

vehicle safety researchers have used the 

THOR–50M to evaluate vehicle 

crashworthiness and develop occupant 

protection countermeasures for frontal 

and oblique crashes. The European New 

Car Assessment Programme (Euro 

NCAP) has officially adopted the 

THOR–50M and is currently rating 

vehicles using the dummy. Moreover, 

the Economic Commission for Europe is 

considering adopting the THOR–50M 

for use in frontal crash testing under its 

vehicle safety regulations. 

NHTSA expects a variety of benefits 

from incorporating the THOR–50M into 

Part 572. The definition of the THOR– 

50M in Part 572 will enable its use in 

regulatory and consumer information 

programs, both within NHTSA and 

externally. NHTSA believes that the 

THOR–50M’s enhancements will lead to 

more effective restraint system designs 

and more informative comparisons of 

the safety of different vehicles. Because 

of this—as well as the fact that 

manufacturers are already using the 

dummy—we believe vehicle 

manufacturers would choose to certify 

vehicles to FMVSS No. 208 using the 

THOR–50M if given the option. This 

would enable manufacturers to 

streamline testing by using the same 

dummy for research and development 

and to verify compliance. NHTSA 

anticipates issuing a proposal in the 

near future to amend FMVSS No. 208 to 

specify the THOR–50M as an alternative 

(at the vehicle manufacturer’s option) to 

the HIII–50M test dummy for use in 

frontal crash compliance tests. There 

would be other benefits as well. For 

instance, NHTSA’s test dummies are 

used in a range of applications beyond 

FMVSS compliance testing—such as 

NCAP testing, standards and regulations 

in other transportation modes, and 

research. Including the dummy design 

in Part 572 will help provide a suitable, 

standardized, and objective test tool for 

the safety community. 

II. Background 

This document proposes to amend 49 

CFR part 572, Anthropomorphic Test 

Devices, to include an advanced test 

dummy representing a 50th percentile 

adult male, the Test Device for Human 

Occupant Restraint (THOR–50M).2 The 

THOR–50M is a test dummy designed 

for use in frontal crash tests. It has 

several advanced capabilities and 

advantages over the Hybrid III 50th 

percentile male test dummy (HIII–50M) 

that is currently specified in Part 572 

and used in frontal crash testing under 

FMVSS No. 208, ‘‘Occupant crash 

protection,’’ and the U.S. New Car 

Assessment Program (NCAP).3 NHTSA 

plans to issue a proposal in the near 

future to amend FMVSS No. 208 to 

specify the THOR–50M as an alternative 

to the HIII–50M for use in frontal crash 

tests.4

This document proposes 

incorporating by reference in Part 572 a 

parts list, design drawings, qualification 

procedures, and procedures for 

assembly, disassembly, and inspection, 

to ensure that THOR–50M dummies are 

uniform in design, construction, and 

response. This section provides 

background on NHTSA’s crash test 

dummies, the development of the 

THOR–50M, and its use in other 

jurisdictions, among other topics. 

Overview of Use of Vehicle Crash Test 

Dummies 

Anthropomorphic Test Devices 

(ATDs)—or crash test dummies—are 

complex instruments that serve as 

human surrogates in vehicle crash tests 

(among other types of tests 5). Test 

dummies simulate the response of a 

human occupant in a crash and measure 


ddrumheller on DSK120RN23PROD with PROPOSALS4
61898 Federal Register / Vol. 88, No. 172 / Thursday, September 7, 2023 / Proposed Rules 

6The FMVSS specify the procedures NHTSA will 

use in compliance testing, including what dummies 

it will use for testing. Part 572 specifies the 

dummies. While manufacturers must exercise 

reasonable care in certifying that their products 

meet applicable standards, they are not required to 

follow the compliance test procedures set forth in 

a standard or use the dummy specified in Part 572. 

See, e.g., 38 FR 12934, 12935 (May 17, 1973) 

(‘‘Manufacturers should understand that they are 

not required to test their products in any particular 

manner, as long as they exercise due care that their 

products will meet the requirements when tested by 

the NHTSA under the procedures specified in the 

standard.’’). 

7Other FMVSS specify different types of crash or 

sled tests that use different dummies. For example, 

FMVSS No. 214, Side Impact Protection, specifies 

two crash tests (simulating a side impact with a 

vehicle and a pole impact). This test uses two 

different side impact dummies. 

8Part 572, Subpart E. 

9 51 FR 26688 (July 25, 1986) (final rule adding 

HIII–50M). The Hybrid III–50M was developed by 

General Motors and added to Part 572 and for use 

in FMVSS No. 208 in response to a petition for 

rulemaking from GM. 

10This reflects a ‘‘bookend’’ approach to testing 

vehicles for crashworthiness, in which a range of 

occupant types, bookended by an average male and 

a small-stature female, is tested. NHTSA is 

currently supporting research to assess the possible 

benefits of developing new crash test dummies, 

such as a 50th percentile female crash test dummy. 

11S5.1.1(b)(2), S14.5.1(b). 

12S5.1.2(b), S14.5.2. 

13S6.2(b). 

14S6.3. 

15S6.4. 

16S6.5. 

17S6.6. 

18Haffner, M., Rangarajan, N., Artis, M., Beach, 

D., Eppinger, R., Shams, T., ‘‘Foundations and 

Elements of the NHTSA THOR Alpha ATD Design,’’ 

The 17th International Technical Conference for the 

Enhanced Safety of Vehicles, Paper No. 458, 2001. 

the effects of the crash forces on the 

occupant. They are used to estimate the 

severity of the injuries that would have 

been experienced by a human occupant 

in a similar crash in the real world. Each 

type of test dummy is designed for use 

in specific types of crashes (frontal, 

side, etc.), and is instrumented with a 

wide array of sensors to measure the 

forces that would be relevant in the type 

of crash for which it is designed and to 

assess the potential for injury. The more 

closely a dummy represents how an 

actual human would respond, the more 

biofidelic the dummy is considered to 

be. 

NHTSA and the vehicle safety 

community use crash test dummies in a 

variety of ways. NHTSA uses crash test 

dummies for vehicle compliance testing, 

safety ratings, and safety research. 

NHTSA’s Federal Motor Vehicle Safety 

Standards establish mandatory 

minimum safety performance 

requirements for motor vehicles and 

motor vehicle equipment. Vehicles and 

equipment manufactured for sale in the 

United States must be certified to 

comply with all applicable FMVSSs. A 

number of the FMVSSs specify crash 

tests, using specified dummies, that the 

vehicle must be certified as passing.6

NHTSA’s vehicle safety compliance 

program selects vehicles (and 

equipment) for compliance testing every 

year; this includes crash testing vehicles 

to ensure that they comply with the 

performance requirements that are 

evaluated by means of crash tests. 

NHTSA’s NCAP also evaluates vehicle 

performance in crash tests using 

dummies as part of its 5-Star Safety 

Ratings. Finally, NHTSA’s vehicle safety 

research program uses crash test 

dummies to evaluate new vehicle safety 

countermeasures and develop new 

vehicle crash testing protocols. 

Dummies are also used outside of 

NHTSA by regulatory authorities in 

other countries and regions, for thirdparty ratings (such as Insurance Institute 

for Highway Safety ratings), and by 

industry and the vehicle safety 

community to measure performance and 

design safer vehicles. 

The dummies NHTSA currently uses 

in FMVSS compliance testing and in 

NCAP are documented in 49 CFR part 

572, Anthropomorphic Test Devices. 

Part 572 sets out detailed design 

information, including engineering 

drawings and procedures for assembly 

and inspection. These are all intended 

to describe the dummy with sufficient 

detail so that it produces consistent 

responses when it is tested under 

similar conditions in repeated tests at 

the same laboratory (repeatability) or 

between multiple dummies 

manufactured to the same specification 

used at different test laboratories 

(reproducibility). 

FMVSS No. 208 Frontal Crash Tests 

Using a 50th Percentile Male Dummy 

FMVSS No. 208, ‘‘Occupant crash 

protection,’’ specifies a variety of 

different requirements using crash test 

dummies. This includes frontal crash 

tests in which the vehicle is moving and 

tests that are performed with a 

stationary vehicle and are intended to 

help ensure that air bags do not harm 

small-stature occupants and children. 

The test dummies used in FMVSS No. 

208 were designed to evaluate vehicle 

performance in frontal crashes and are 

fitted with a variety of instruments to 

measure the forces typically 

experienced by an occupant in a frontal 

crash.7 The 50th percentile male 

dummy that is currently specified for 

use in FMVSS No. 208 is the Hybrid III– 

50M.8 The HIII–50M has been specified 

in FMVSS No. 208 since 1986,9 and 

replaced an even earlier dummy, the 

Hybrid II. FMVSS No. 208 also specifies 

tests using dummies representing a 5th 

percentile female, a 6-year-old, a 3-yearold, and an infant.10

FMVSS No. 208 specifies two tests 

(both of which are crash tests) using the 

HIII–50M: a crash test in which the 

dummy is belted and the test vehicle, 

traveling up to 35 mph, impacts a rigid 

barrier at a ninety-degree angle or 

perpendicular; 11 and a crash test in 

which the dummy is unbelted and the 

test vehicle, traveling 20–25 mph, 

impacts a rigid barrier at an angle 

ranging from ± 30 degrees oblique from 

perpendicular.12 NCAP also evaluates 

vehicle performance in a frontal crash 

test at 35 mph using a belted HIII–50M 

dummy. 

FMVSS No. 208 regulates vehicle 

performance in these crash tests by 

specifying injury criteria and associated 

injury assessment reference values 

(IARVs). Injury criteria and their 

respective risk functions relate 

instrumentation measurements to a 

predicted risk of human injury. Each 

IARV is a maximum value or threshold 

for a specific injury criterion that may 

not be exceeded when the vehicle is 

tested with the specified dummy under 

the specified test conditions and 

procedures. For example, FMVSS No. 

208 specifies a head injury criterion, 

HIC15, with an IARV of 700. Thus, if 

NHTSA runs a compliance frontal crash 

test and the calculated HIC15 value 

exceeds 700, this would be considered 

an apparent noncompliance. FMVSS 

No. 208 specifies the following injury 

criteria for the HIII–50M: a head injury 

criterion (HIC15); 13 a thoracic 

acceleration criterion; 14 a chest 

deflection criterion; 15 a criterion based 

on the maximum force transmitted 

axially through the upper leg (femur); 16

and three neck injury criteria.17

Development of the THOR ATDs 

NHTSA has continually conducted 

research into advancements in crash 

safety, including the development of 

advanced dummies.18 The goal of this 

research has been to create ATDs that 

represent the responses of human 

occupants in modern vehicle 

environments with advanced restraint 

systems. This research has led to the 

development of the two Test Device for 

Human Occupant Restraint (THOR) 

ATDs, designed primarily for use in 

frontal and frontal oblique motor 

vehicle crash environments. There are 

currently two main implementations of 

the THOR design, both representing 

seated motor vehicle occupants: one 

representing a 50th percentile male and 


ddrumheller on DSK120RN23PROD with PROPOSALS4
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19 Id. 

20Shams, T., Rangarajan, N., McDonald, J., Wang, 

Y., Platten, G., Spade, C., Pope, P., Haffner, M., 

‘‘Development of THOR NT: Enhancement of THOR 

Alpha—the NHTSA Advanced Frontal Dummy,’’ 

The 19th International Technical Conference for the 

Enhanced Safety of Vehicles, Paper No. 05–0455, 

2005. 

21Ridella, S., Parent, D., ‘‘Modifications to 

Improve the Durability, Usability, and Biofidelity of 

the THOR–NT Dummy,’’ The 22nd International 

Technical Conference for the Enhanced Safety of 

Vehicles, Paper No. 11–0312, 2011. 

22Lemmen, P., Been, B., Carroll, J., Hynd, D., 

Davidsson, J., Song, E., Lecuyer, E., ‘‘Development 

of an advanced frontal dummy thorax 

demonstrator,’’ Proceedings of the 2012 IRCOBI 

Conference, 2012. 

23National Highway Traffic Safety 

Administration (2015). Parts List and Drawings, 

THOR–M Advanced Frontal Crash Test Dummy, 

September 2015. Regulations.gov Docket ID 

NHTSA–2015–0119–0005, available at: https://

www.regulations.gov/document/NHTSA-2015-0119- 

0005 (NCAP docket). 

24National Highway Traffic Safety 

Administration (2016). Parts List and Drawings, 

THOR–50M Advanced Frontal Crash Test Dummy, 

August 2016, available at: https://www.nhtsa.gov/ 

es/document/thor-50m-drawing-package-august2016.pdf. 

25National Highway Traffic Safety 

Administration. Parts List and Drawings, THOR– 

50M Advanced Frontal Crash Test Dummy, August 

2018. Regulations.gov Docket ID NHTSA–2019– 

0106–0002, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0002. 

26National Highway Traffic Safety 

Administration. THOR 50th Percentile Male with 

Alternate Shoulders Frontal Crash Test Dummy 

Drawings, External Dimensions, and Mass 

Properties, THOR–50M Advanced Frontal Crash 

Test Dummy, August 2018. Regulations.gov Docket 

ID NHTSA–2019–0106–0013, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0013. 

27 Docket NHTSA–2019–0106. 

28These documents are located in the research 

docket, Docket No. NHTSA–2019–0106. NHTSA is 

not placing copies of these documents in the docket 

for this rulemaking action in order to avoid 

potential confusion from having identical 

documents docketed at different times in different 

dockets. Nevertheless, NHTSA intends these to be 

included as part of the rulemaking record for this 

rulemaking action. A memorandum explaining this 

is also being placed in the docket for this 

rulemaking. 

29See National Highway Traffic Safety 

Administration (2022). NHTSA Female Crash Safety 

Research Plan, November 2022. Regulations.gov 

Docket ID NHTSA–2022–0091–0002, available at: 

https://www.regulations.gov/document/NHTSA2022-0091-0002. 

one representing a 5th percentile 

female. 

Development of THOR–50M 

The initial design version of the 

THOR–50M, introduced in 2001, was 

the THOR Alpha.19 The THOR Alpha, 

which integrated some components 

from the earlier prototype demonstrator 

known as the Trauma Assessment 

Device, introduced some of the features 

that exist in the current version of 

THOR–50M, including the multidirection neck, human-like ribcage 

geometry and impact response, multipoint thorax and abdomen deflection 

measurement system, and instrumented 

lower extremities. NHTSA refined the 

THOR Alpha design and reintroduced it 

in 2005 as the THOR–NT,20 which 

included updates to anthropometry, 

durability, usability, biofidelity, and fit 

and finish. In 2011, NHTSA, in 

coordination with the SAE International 

(SAE) THOR Evaluation Task Group, 

introduced a modification package (Mod 

Kit) intended to enhance the biofidelity, 

repeatability, durability, and usability of 

the THOR–NT.21 After the introduction 

of the THOR Mod Kit, an upgrade to the 

Chalmers shoulder assembly that was 

developed through the European 

Union’s THORAX project was integrated 

into the THOR–50M design.22 The 

THOR–50M drawing package was then 

converted from the traditional 

measurement system to the metric 

system through soft conversion (where 

any non-metric measurements are 

mathematically converted to metric 

equivalents without changes to the 

physical dimensions). All fasteners were 

also replaced with the nearest metric 

equivalents. NHTSA made this 

integrated drawing package (with 

incremental improvements and 

corrections) publicly available online in 

2015,23 2016,24 2020,25 and 2023.26 The 

version published in 2023 is referred to 

as the 2023 drawing package, which 

consists of two-dimensional drawings 

and a Parts list; this, together with the 

Procedures for Assembly, Disassembly, 

and Inspection (PADI), and qualification 

procedures, is referred to as the 2023 

technical data package. (The version 

published in 2020 is referred to as the 

‘‘2018 drawing package’’ or the ‘‘2018 

technical data package.’’) The version of 

THOR that is being proposed is the 

version defined in the 2023 technical 

data package. In 2019, NHTSA began 

publishing THOR–50M documentation 

in a new docket titled, ‘‘NHTSA 

Crashworthiness Research—THOR–50M 

Documentation.’’ 27 In addition to the 

documents that make up the 2018 and 

2023 technical data packages, the docket 

folder includes the following: durability 

report; seating procedure; injury criteria; 

biofidelity report; Oblique Moving 

Deformable Barrier (OMDB) 

Repeatability and Reproducibility 

(R&R); and Qualification test R&R. This 

documentation is discussed further in 

Section III.B and in the relevant sections 

of this preamble.28 NHTSA has 

tentatively concluded that the THOR– 

50M is sufficiently biofidelic, exhibits 

repeatable and reproducible 

performance, and is sufficiently durable. 

As such, we believe that it would be 

suitable for use in regulatory 

compliance testing and is therefore 

suitable for incorporation into Part 572. 

A more detailed discussion of the 

technical data package is provided in 

Section III.B. 

Development of THOR–05F 

NHTSA understands that the risk of 

injury in a crash can depend on the 

occupant’s physical characteristics (e.g., 

height, weight, bone density) and how 

they interact with the restraint system 

and vehicle environment. To that end, 

NHTSA has developed comprehensive 

research plans to address differences in 

crashworthiness safety testing and 

outcomes, including differences in 

injury risk. Human body modeling 

research efforts are underway to 

consider female and male occupants 

and vulnerable road users of various 

ages, shapes, and sizes. This includes 

continuing and accelerating research 

efforts to address differences in motor 

vehicle safety based on physical 

characteristics, including sex, and 

making data-driven decisions supported 

by the research outcomes. A series of 

efforts is specifically focused on female 

occupant crash safety, spanning field 

data analysis, tool development, 

demonstration, and application.29

As part of these efforts, NHTSA has 

been developing the THOR 5th 

percentile adult female frontal crash test 

dummy (THOR–05F). The THOR–05F 

represents a small adult female and has 

a seated height of 81.3 cm (32.0 in), 

approximate standing height of 151 cm 

(59.4 in), and weight of 49 kg (108.0 

lbs). The THOR–05F has improved 

measurement capabilities over the 

Hybrid III–5F, which is specified in 

FMVSS No. 208 and documented in Part 

572. The THOR–05F’s instrumentation 

is similar to that of the THOR–50M. 

Improved designs resulting from the 

development of the THOR–50M related 

to the head, neck, thorax, and lower 

extremities have also been incorporated 

into the design of the THOR–05F. 

Currently, NHTSA is evaluating the 

THOR–05F’s biofidelity and durability, 

developing design updates, injury 

criteria, and documentation, and 

assessing its utility in full-scale crash 

testing. 

NHTSA anticipates completing the 

research and testing necessary to 

support a rulemaking for the THOR–05F 


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30Part 572 THOR 5th Female Crash Test Dummy 

(RIN 2127–AM56), Spring 2023 Unified Agenda of 

Regulatory and Deregulatory Actions; Department 

of Transportation, available at https://

www.reginfo.gov/public/do/eAgendaViewRule?

pubId=202304&RIN=2127-AM56. This rulemaking 

would amend 49 CFR part 572 by adding design 

and performance specifications for a new test 

dummy known as the THOR–05F. 

31See Docket No. NHTSA–2019–0107, available 

at regulations.gov. 

32 Data Sources: Fatality Analysis Reporting 

System (FARS): 2017–2020 Final File and 2021 

Annual Report File (ARF); Report Generated: 

Wednesday, June 28, 2023 (12:48:52 p.m.); 

VERSION 5.6, RELEASED MAY 19, 2023 

33Charles J. Kahane, Lives Saved by Vehicle 

Safety Technologies and Associated Federal Motor 

Vehicle Safety Standards, 1960 to 2012—Passenger 

Cars and LTVs—With Reviews of 26 FMVSS and 

the Effectiveness of Their Associated Safety 

Technologies in Reducing Fatalities, Injuries, and 

Crashes. 89 DOT HS 812 069 at 89, Department of 

Transportation, National Highway Traffic Safety 

Administration (2015). 

34Craig, M., Parent, D., Lee, E., Rudd, R., 

Takhounts, E., Hasija, V. (2020). Injury Criteria for 

the THOR 50th Male ATD. Regulations.gov Docket 

ID NHTSA–2019–0106–0008, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0008. 

35Sunneva ̊ng, C., Hynd, D., Carroll, J., Dahlgren, 

M., ‘‘Comparison of the THORAX Demonstrator and 

HIII Sensitivity to Crash Severity and Occupant 

Restraint Variation,’’ Proceedings of the 2014 

IRCOBI Conference, Paper No. IRC–14–42, 2014. 

36Hardesty, J. (2021). Next-Generation Passenger 

Airbag. SAE Government-Industry Digital Summit 

(oral only). 

37See also, e.g., Hu, J., Reed, M. P., Rupp, J. D., 

Fischer, K., Lange, P., & Adler, A. (2017). 

Optimizing seat belt and airbag designs for rear seat 

occupant protection in frontal crashes (No. 2017– 

22–0004). SAE Technical Paper; Eggers, A., 

Eickhoff, B., Dobberstein, J., Zellmer, H., Adolph, T. 

(2014). Effects of Variations in Belt Geometry, 

Double Pretensioning and Adaptive Load Limiting 

on Advanced Chest Measurements of THOR and 

Hybrid III. Proceedings of the 2014 IRCOBI 

Conference, Paper No. IRC–14–40; Hu, J., Fischer, 

K., Schroeder, A., Boyle, K., Adler, A., & Reed, M. 

(2019, October). Development of oblique restraint 

countermeasures (Report No. DOT HS 812 814). 

Washington, DC: National Highway Traffic Safety 

Administration. Available at: https://

rosap.ntl.bts.gov/view/dot/44143. 

38European Commission, Seventh Framework 

Programme, THORAX Project Final Report, 

in 2023.30 Possible test modes in which 

THOR–05F may be used include 

FMVSS No. 208 testing and NCAP 

frontal crash tests. NHTSA has placed 

documentation and research for the 

THOR–05F in an online docket and will 

continue adding additional research and 

information to this docket as it becomes 

available.31

Innovative Features of the THOR–50M 

Frontal crashes are the leading cause 

of injuries and fatalities in occupants of 

motor vehicle crashes on U.S. public 

roadways. The vehicle front is the initial 

point of impact in a majority of crashes 

in the U.S. In 2021, 15,570 occupants of 

passenger cars or light trucks died, and 

1,144,169 were injured, in frontal 

crashes.32 This suggests that even 

though occupant protection systems 

have improved over the years and saved 

many lives,33 improvements to 

occupant protection in frontal crashes 

still need to be made. 

The THOR–50M is designed to better 

evaluate the effectiveness of modern 

vehicle restraint systems and address 

the types of injuries that continue to 

occur. These improvements include the 

following: 

Improved biofidelity. Biofidelity is a 

measure of how well a dummy 

replicates the response of a human. The 

THOR–50M was designed with 

advanced features that enable it to have 

improved biofidelity compared to the 

HIII–50M. The dummy’s head includes 

a deformable facial insert that emulates 

human response to impact. The 

components in the neck representing 

bone and ligament structure are separate 

from those representing muscular 

structure, improving both kinematic 

response and injury prediction. The 

thorax simulates the shape and impact 

response of the human rib cage. The 

spine incorporates flexible joints in the 

thoracic and lumbar spine, allowing 

dynamic spine flexion as well as static 

adjustment in the neck and lumbar 

spine to accommodate seating in various 

postures. The upper leg has a 

compressive element in the femur and 

the lower leg has a compressive element 

in the tibia and an Achilles tendon load 

path to achieve human-like impact 

response. The biofidelity of the THOR– 

50M has been assessed in a wide array 

of both component and full-body test 

conditions for which human response is 

known and was found to be both 

qualitatively and quantitatively 

congruent with human response 

corridors. 

Improved instrumentation. The 

THOR–50M has both improved and 

additional instrumentation compared to 

the HIII–50M. The thorax 

instrumentation measures the threedimensional deformation of the rib cage 

at four locations. The abdomen is also 

designed with a multi-point 

measurement system that monitors 

three-dimensional deformation of the 

abdomen at two locations. The upper 

leg includes an acetabulum load cell in 

the pelvis to measure load transfer from 

the femur to the hip. The lower leg has 

extensive instrumentation to support 

injury risk calculation. 

Improved injury prediction. The 

biofidelity of the THOR–50M, combined 

with its extensive instrumentation, 

provides an enhanced capability to 

measure expected human response and 

predict injury. Injury criteria and injury 

risk functions, which relate 

instrumentation measurements to a 

predicted risk of human injury, have 

been developed for the head, neck, 

chest, abdomen, pelvis, upper leg, and 

lower leg of the THOR–50M.34 These 

include injury criteria analogous to 

those currently specified for the HIII– 

50M in FMVSS No. 208 as well as injury 

criteria that are not currently specified 

for the HIII–50M in FMVSS No. 208. We 

believe this enhanced injury prediction 

capability will translate into restraint 

system designs that have the potential to 

enhance occupant protection. NHTSA 

and others, including vehicle 

manufacturers, have already taken 

advantage of these capabilities in the 

research arena. 

Improved evaluation of vehicle 

performance. These enhancements 

allow the THOR–50M to better 

differentiate the performance of 

different vehicles and restraint systems. 

The more sophisticated measurement 

capabilities of an advanced ATD are 

better suited to develop and test more 

sophisticated and highly tunable 

contemporary restraint systems with 

features such as multi-stage air bags and 

force-limiting/pretensioning seat belts. 

Motor vehicle manufacturers and 

restraint suppliers have already used the 

THOR–50M to evaluate vehicle 

crashworthiness and develop occupant 

protection countermeasures. Numerous 

conference and journal articles 

describing the use of the THOR–50M 

have been published. For example, in a 

study examining the performance of 

different restraint systems in frontal 

impact sled tests using both the THOR– 

50M and HIII–50M, the THOR–50M was 

found to be more sensitive to the 

restraint conditions, as it was able to 

differentiate between both crash severity 

and restraint performance.35 Another 

study investigated a novel air bag 

system with three inflated chambers 

with a connected sail panel to promote 

earlier engagement with the occupant 

and prevent lateral motion and head 

rotation; sled testing using the THOR– 

50M demonstrated a reduction in brain 

injury risk due to head angular velocity, 

as quantified using the Brain Injury 

Criterion (BrIC).36 Other studies have 

also implemented the THOR–50M to 

assess and develop restraint systems.37

Adoption of the THOR–50M in Europe 

In 2013, the European Commission 

(EC) issued a final report detailing the 

need for a new crash test dummy as a 

means to implement regulatory 

requirements for new vehicle safety 

technologies, particularly those 

technologies that reduce thorax injuries 

in frontal crashes.38 At the time, the 


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Thoracic injury assessment for improved vehicle 

safety, 1/7/2013. 

39Seidl, M., Edwards, M., Barrow, A., Hynd, D., 

& Broertjes, P. (2017). The Expected Impact of UN 

Regulation No. 137 Tests on European Cars and 

Suggested Test Protocol Modifications to Maximise 

Benefits. In 25th International Technical 

Conference on the Enhanced Safety of Vehicles 

(ESV). 

40Seidl M, Hynd D, McCarthy M, Martin P, Hunt 

R, Mohan S, Krishnamurthy V and O’Connell S: 

TRL Ltd. (2017). In depth cost-effectiveness analysis 

of the identified measures and features regarding 

the way forward for EU vehicle safety, Final Report, 

ISBN 978–92–79–68704–4, European Commission, 

08–31–2017. 

41Seidl, M., Khatry, R., Carroll, J., Hynd, D., 

Wallbank, C., Kent, J. (2018) Cost-effectiveness 

analysis of Policy Options for the mandatory 

implementation of different sets of vehicle safety 

measures—Review of the General Safety and 

Pedestrian Safety Regulations, Technical Annex to 

GSR2 report SI2.733025. 

42This was a thrice-annual briefing on the 

regulatory status within the various working parties 

under WP.29’s World Forum for Harmonization of 

Vehicle Regulations, including the status of R137 

under the Working Party for Passive Safety (GRSP). 43WP.29–177–18, 177th WP.29, 12–15 March 

2019, EU Work priorities for 2019–2021 for UNECE 

activities. 44TRL serves as an independent advisory to the 

E.C. TRL’s report was performed under contract 

with the European Commission (E.C.), who sought 

to update the General Safety Regulation for Europe 

to include new and developing technologies with 

the aim of reducing Europe’s annual road fatalities. 

The report reflects TRL’s recommendations for 

consideration by the E.C. 

45 General Safety Regulation: Technical study to 

assess and develop performance requirements and 

test protocols for various measures implementing 

the new General Safety Regulation, for accident 

avoidance and vehicle occupant, pedestrian and 

cyclist protection in case of collisions, Final Report, 

March 2021, Publications Office of the EU 

(europa.eu)), ISBN 978–92–76–08556–0, DOI 

10.2873/499942, Catalogue number, ET–04–19– 

467–EN–N. https://op.europa.eu/en/publicationdetail/-/publication/6987b729-a313-11eb-9585- 

01aa75ed71a1/language-en/format-PDF/source217672351 (last accessed 5/25/2023). 

46Mutual Resolution No. 1 (M.R.1) of the 1958 

and the 1998 Agreements. Concerning the 

description and performance of test tools and 

devices necessary for the assessment of compliance 

of wheeled vehicles, equipment and parts according 

to the technical prescriptions specified in 

Regulations and global technical regulations, ECE/ 

TRANS/WP.29/1101, 10 January 2013. 

47European New Car Assessment Programme 

(2022). MPDB Frontal Impact Testing Protocol, 

Version 1.1.3, available at: https://

www.euroncap.com/en/for-engineers/protocols/ 

adult-occupant-protection/. 

48European New Car Assessment Programme 

(2023). THOR Specification and Certification, 

Version 1.3, available at: https://

www.euroncap.com/en/for-engineers/supportinginformation/technical-bulletins/. 

49 § 1.1. 

50 § 2.1. 

51 § 3.1. 

THOR–50M was envisioned as the best 

evaluation tool for this purpose. In 

2015, United Nations Economic 

Commission for Europe (UNECE) 

Regulation No. 137 (R137) went into 

effect. R137 specifies a 50 km/h, fullwidth rigid barrier frontal impact test 

with driver and passenger HIII–50M and 

HIII–5F dummies respectively. One 

objective of the regulation was to 

encourage better restraint systems across 

a wider range of collision severities.39

In 2017, an ECE-funded study found 

that the R137 condition and dummy 

diversity were not sufficiently different 

to existing UN Regulation No. 94 (R94) 

to force improvements in restraint 

systems. R94 involves a 56 km/h frontal 

offset test which also prescribes the 

HIII–50M in the driver and right front 

seat. To deliver the expected benefits, 

the 2017 final report recommended 

implementation of the THOR–50M in 

R137 as a replacement for the HIII– 

50M.40 The THOR–50M was recognized 

as being more biofidelic in its 

representation of thoracic response and 

prediction of thorax injuries, which are 

the key serious and fatal injury types in 

full-width collisions targeted by R137. 

In 2018, the EC published a report on 

the cost-effectiveness and the number of 

future injuries and fatalities that could 

be prevented at a European level for 

different sets of vehicle safety 

measures.41 Several new sets of safety 

measures were considered for 

mandatory implementation in new 

vehicles starting from 2022. This 

included the introduction of the THOR– 

50M into R137. The THOR–50M was 

considered for inclusion in a program 

titled ‘‘Full-width Frontal Occupant 

Protection with THOR (FFW–THO),’’ 

which would lower injury criteria 

thresholds to encourage implementation 

of adaptive restraints. It was envisioned 

that the implementation of the THOR– 

50M would result in an initial cost of 16 

Euros per vehicle, for vehicles that 

currently comply with UN Regulation 

No. 137 with Hybrid III ATDs but not 

with THOR–50M ATDs. It was 

estimated that vehicles that comply 

with FFW–THO would provide a 6% 

increase in effectiveness in protecting 

against serious injuries compared to 

vehicles that comply with R137 alone. 

In 2019, the EC presented work 

priorities to WP.29 42 for 2019–2021 for 

UNECE activities. An amendment to 

introduce the THOR–50M into R137 

was included. The target date for a 

WP.29 vote was listed as Q4/2021.43 In 

2020, Japan and the EC jointly initiated 

discussions within WP.29 to establish a 

priority for the new task. In preparation 

for an eventual adoption into R137, the 

E.C. commissioned TRL (Transport 

Research Laboratory, UK) 44 to conduct 

a survey of various stakeholders on the 

readiness of the THOR–50M. ATD 

manufacturers, crash test laboratories, 

and crash safety research laboratories 

were consulted. The results of the 

survey are contained within Annex 7 of 

a broader report on general safety 

regulations, published by the E.C. in 

2021.45 In the E.C. report, there are a 

number of recommendations based on 

stakeholder feedback. They include 

revisions to the dummy design and 

qualification procedures that may be 

needed prior to adopting THOR–50M 

into M.R. 1 46 and R137. Most 

stakeholders recommended the 

formation of either an Informal Working 

Group or a Technical Evaluation Group 

under the umbrella of UNECE WP.29 to 

co-ordinate this activity. As of May 

2023, a WP.29 working group has yet to 

be established and timelines for 

amendments to R137 and M.R. 1 are 

undetermined. The areas for further 

investigation identified in Annex 7 are 

discussed in this NPRM. 

Although the ECE has not yet 

officially adopted the THOR–50M, the 

European New Car Assessment 

Programme (Euro NCAP) has been rating 

vehicles using the dummy. Euro NCAP 

has implemented a moving progressive 

deformable barrier (MPDB) frontal 

impact testing protocol with a THOR– 

50M in the driver’s seat.47 The THOR– 

50M used by Euro NCAP is specified in 

Technical Bulletin 026 (TB026) 48

‘‘THOR Specification and 

Certification.’’TB026 explicitly adopts— 

with some variations—NHTSA’s 2018 

technical data package (i.e., the 2018 

drawing package,49 qualification 

procedures,50 and PADI 51). The 

variations to the 2018 technical data 

package are relatively limited. For 

example, TB026 specifies an onboard 

(in-dummy) data acquisition system and 

a variation to the adjustable spine to 

facilitate data acquisition system (DAS) 

installation; minor deviations in the 

shoulder assembly; and the use of the 

HIII–50M lower legs. These 

modifications are discussed in more 

detail in the relevant sections of the 

preamble and are summarized in 

Section IX, Consideration of 

alternatives. NHTSA’s understanding is 

that no regulatory authorities or thirdparty vehicle rating programs other than 

Euro NCAP currently specify the 

THOR–50M for use in vehicle crash 

tests. 

Motor vehicle and equipment 

manufacturers’ interest in the design 

and operation of the THOR–50M has 

been heightened since the dummy was 

introduced into Euro NCAP and plans 

for R137 were announced. Discussions 

are taking place within International 

Standards Organization (ISO) Technical 

Committee 22 (Road Vehicles), SubCommittee 36 (Safety and impact 

testing), Working Group 5 

(Anthropomorphic test devices) for 


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52FMVSS No. 208 THOR–50M Compliance 

Option (RIN 2127–AM21), Fall 2023 Unified 

Agenda of Regulatory and Deregulatory Actions; 

Department of Transportation, available at https:// 

www.reginfo.gov/public/do/eAgendaViewRule?

pubId=202304&RIN=2127-AM21. This rulemaking 

would propose injury assessment reference values 

for the THOR–50M comparable to the IARVs 

currently specified for the HIII–50M. 

53Forman, J., Caudillo-Huerta, A., McMahon, J., 

Panzer, M., Marshall, W., Winter, D., Dyer, M., 

Lemmen, P. (2021). Modifications to the THOR– 

50M for Improved Usability in Reclined Postures— 

Update and Preliminary Findings. 2021 SAE 

Government-Industry Digital Summit, available at: 

https://www.nhtsa.gov/node/103691. The 

adaptation to the THOR–50M design for use in 

reclined seating environments is outside of the 

scope of this Part 572 NPRM. 

54 49 CFR 572.1. 

55For example, American Public Transportation 

Association standard APTA PR–CS–S–018–13 Rev. 

1 describes the use of a THOR ATD in the testing 

of fixed workstation tables in passenger rail cars. 

American Public Transportation Association. (2015, 

October). Fixed Workstation Tables in Passenger 

Rail Cars. PR–CS–S–018–13, Rev. 1. Washington, 

DC, available at: https://www.apta.com/wp-content/ 

uploads/Standards_Documents/APTA-PR-CS-S018-13-Rev-1.pdf. 

56Schneider, L.W., Robbins, D.H., Pflug, M.A., 

Snyder, R. G., ‘‘Development of Anthropometrically 

Based Design Specifications for an Advanced Adult 

Anthropomorphic Dummy Family; Volume 1- 

Procedures, Summary Findings and Appendices,’’ 

U.S. Department of Transportation, DOT–HS–806– 

715, 1985. 

57Robbins, D.H., ‘‘Development of 

Anthropometrically Based Design Specifications for 

an Advanced Adult Anthropomorphic Dummy 

Family; Volume 2-Anthropometric Specifications 

for mid-Sized Male Dummy; Volume 3- 

Anthropometric Specifications for Small Female 

and Large Male Dummies,’’ U.S. Department of 

Transportation, DOT–HS–806–716 & 717, 1985. 

58A THOR–50M unit is a collection of serialized 

parts that can be swapped out with other dummies, 

so is not considered a ‘‘serialized’’ dummy. Indeed, 

many of the subassemblies that were part of S/N 

9798 when NHTSA took these measurements were 

subsequently swapped out of the dummy. See 

Section VII.A. 

59These AMVO measurements were collected as 

an assessment of anthropometry; it is understood 

that there is variation in initial position and 

measurement methodology that prevents the use of 

such measurements as a repeatable dimensional 

assessment. In practice, a simplified set of 

dimensional requirements are put in place as a 

check for overall part fit, tolerance stack, and to 

ensure that the dummy is assembled correctly. 

These requirements are specified on drawing 472– 

0000, Sheet 4, and are collected following the 

‘‘Procedures for Measuring External Dimensions’’ 

section of the PADI. 

modifications suggested by 

manufacturers. With no defined 

European entity to maintain 

configuration control, ISO has enlisted 

Humanetics Innovative Solutions, Inc. 

(Humanetics) to investigate its change 

recommendations directly. In particular, 

discussions have taken place regarding 

modifications to the shoulder pad and 

rib guide. These modifications are 

discussed in the relevant sections of the 

NPRM. 

Need for This Rulemaking 

NHTSA expects a variety of benefits 

from incorporating the THOR–50M in 

Part 572. The THOR–50M is an 

advanced dummy with many 

advantages over existing dummies with 

respect to biofidelity, instrumentation, 

and injury prediction. NHTSA believes 

that the THOR–50M’s enhancements 

will lead to more effective restraint 

system designs and more informative 

comparisons of the safety of different 

vehicles. Euro NCAP has adopted it, the 

ECE is considering it for use in R137, 

and it is likely being used by vehicle 

and restraint manufacturers for testing, 

research, and development. Therefore, 

we believe vehicle manufacturers would 

choose to certify new vehicles using the 

THOR–50M if given the option, because 

this would enable manufacturers to 

streamline testing by using the same 

dummy for research and development 

and to verify compliance and vehicle 

ratings. NHTSA is therefore also 

considering a proposal to amend 

FMVSS No. 208 to give vehicle 

manufacturers the option of selecting 

the THOR–50M for use in belted and 

unbelted crash testing instead of the 

HIII–50M.52

There would be other benefits as well. 

For instance, the THOR–50M is wellsuited for the types of new seating 

configurations brought on by vehicles 

with Automated Driving Systems (ADS). 

NHTSA is developing an adaptation of 

the THOR–50M that is better suited for 

reclined postures which may be 

prevalent among ADS occupants.53

NHTSA’s test dummies are also used in 

a range of applications beyond FMVSS 

compliance testing—such as NCAP 

testing, standards and regulations in 

other transportation modes, and 

research. While the purpose of Part 572 

is to describe the anthropomorphic test 

devices that are to be used for 

compliance testing of motor vehicles 

and motor vehicle equipment with 

motor vehicle safety standards,54 it also 

serves as a definition of the ATD for 

other purposes, such as consumer 

information crash testing, standards and 

regulations in other transportation 

modes, and research. As such, it would 

be to the benefit of government, 

academia, and the multi-modal 

transportation industry to include a 

definition of the THOR–50M ATD in 

Part 572.55

III. Design, Construction, and 

Instrumentation 

In this section we discuss the 

anthropometry, design, construction, 

and instrumentation of the THOR–50M. 

A. Anthropometry 

The THOR–50M is a physical model 

of a 50th percentile male motor vehicle 

occupant. It is intended for use in the 

development and evaluation of vehicle 

safety countermeasures and vehicle 

safety performance in frontal crash tests. 

To ensure that the dummy responds in 

a human-like manner in a vehicle crash 

environment, it is necessary that the 

size and shape of the dummy, referred 

to as anthropometry, provide an 

accurate representation of a mid-sized 

male. The anthropometry of the THOR– 

50M is based on a study by the 

University of Michigan Transportation 

Research Institute that documented the 

anthropometry of a mid-sized (50th 

percentile in stature and weight) male 

occupant in an automotive seating 

posture (AMVO study).56 57 This study 

defines an average male as 76.57 kg 

(168.8 lb) in weight with a standing 

height of 175.1 cm (68.9 in). The AMVO 

study is currently internationally 

accepted as the standard anthropometry 

for the 50th percentile male ATD. The 

THOR–50M has a mass of 77.37 kg 

(170.6 lb) and a seated height of 101.8 

cm (40.2 in). The standing height of the 

ATD cannot be measured since the 

pelvis does not allow a full standing 

posture; however, since it was 

developed using the AMVO body 

segment geometry and seated 

anthropometry, it is assumed that the 

stature of the THOR–50M is also 175.1 

cm. 

The THOR–50M is consistent with the 

AMVO anthropometry. NHTSA 

compared the dimensions of a 

representative dummy (S/N 9798) with 

the AMVO target dimensions (Table 

1).58 The AMVO procedure originally 

used to collect measurements from 

volunteers was adapted to collect the 

same or similar measurements on the 

THOR–50M.59 Most of these 

measurements were taken with the 

THOR–50M seated on the AMVO bench, 

which has an angled seat and backrest. 

One adaptation was necessary to collect 

leg measurements on the AMVO bench: 

the THOR–50M has an integrated 

molded shoe that cannot be separated 

from its foot, while the AMVO data 

were collected on barefoot volunteers. 

To remedy this situation, the THOR– 

50M measurements were recorded after 

removing the entire molded shoe 

assembly and positioning the center of 

the ankle joint at the same location as 

the AMVO ankle landmark. Another 

adaptation was that four of the 

measurements were collected with the 

THOR–50M seated on a 90-degree 

bench, as specified on drawing 472– 

0000, Sheet 4. NHTSA also compared 


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the body segment masses specified in 

the proposed THOR drawing package 

(472–0000, Sheet 5) with the AMVO 

body segment masses (Table 2), and the 

masses were also consistent. 

TABLE 1—THOR–50M ANTHROPOMETRY COMPARED TO AMVO 

Dimensions 

(all measurements in centimeters) 

AMVO target 

(Robbins et al 

1983) 

THOR–50M 

S/N 9798 

Height of top of head to floor .................................................................................................................................. 100.3 101.8 

Height of shoulder to floor ....................................................................................................................................... 72.1 74.2 

H-point to knee joint distance (note 1) .................................................................................................................... 43.2 42.3 

Buttock to knee end distance (note 2) .................................................................................................................... 59.3 62.0 

Height of knee from floor ......................................................................................................................................... 45.3 47.0 

Head circumference ................................................................................................................................................. 57.1 58.7 

Head top-chin distance ............................................................................................................................................ 19.7 22.9 

Head breadth ........................................................................................................................................................... 15.8 15.3 

Chest circumference ................................................................................................................................................ 101.1 95.5 

Chest breadth .......................................................................................................................................................... 34.9 30.9 

Chest depth (note 3) ................................................................................................................................................ 22.7 22.4 

Abdomen circumference .......................................................................................................................................... 91.3 99.0 

Abdomen breadth .................................................................................................................................................... 32.5 32.5 

Abdomen depth (note 2) .......................................................................................................................................... 26.9 29.8 

Pelvis breadth .......................................................................................................................................................... 38.5 38.8 

Thigh max circumference ........................................................................................................................................ 57.9 56.8 

Thigh max breadth ................................................................................................................................................... 19.4 17.1 

Mid thigh circumference .......................................................................................................................................... 50.4 56.0 

Mid thigh breadth ..................................................................................................................................................... 15.5 17.8 

Calf circumference ................................................................................................................................................... 37.3 37.5 

Calf breadth ............................................................................................................................................................. 11.0 9.1 

Calf depth ................................................................................................................................................................ 11.8 11.9 

1THOR–50M specified on 472–0000, Sh. 4, measurement F (Knee Pivot to Hip Pivot) as seated upright on a 90-degree bench. 

2THOR–50M and AMVO measured as seated upright on a 90-degree bench. 

3THOR–50M specified on 472–0000, Sh. 4, measurement I (Rib #3 depth) as seated upright on a 90-degree bench without jacket installed. 

TABLE 2—THOR–50M BODY SEGMENT MASSES COMPARED TO AMVO 

Body segment masses 

(all measurements in kilograms) 

AMVO target 

(Robbins et al 

1983) 

THOR–50M 

specification * 

Head ........................................................................................................................................................................ 4.137 

** (4.55) 

4.501 

Neck ......................................................................................................................................................................... 0.965 2.363 

Thorax ...................................................................................................................................................................... 23.763 23.517 

Lower Abdomen ....................................................................................................................................................... 2.365 2.664 

Pelvis ....................................................................................................................................................................... 11.414 15.229 

Upper Arm, Left or Right ......................................................................................................................................... 1.769 1.701 

Lower Arm with Hand, Left or Right ........................................................................................................................ 2.022 2.227 

Upper Leg, Left or Right .......................................................................................................................................... 8.614 5.618 

Lower Legs, Left or Right ........................................................................................................................................ 3.587 3.396 

Feet, Left or Right including shoe ........................................................................................................................... *** 1.551 1.604 

Total Weight ..................................................................................................................................................... 76.562 77.366 

* Listed on Drawing No. 472–0000, Sh. 5. 

** Mass reported in Melvin JW, Weber, K. ‘‘Task B Final Report: Review of Biomechanical Impact Response and Injury in the Automotive Environment,’’ U.S. Department of Transportation, DOT–HS–807–042, 1985. The AMVO target is believed to be too low. 

*** This adds the mass of a size 11 Oxford shoe (0.57 kg) specified for use in FMVSS No. 208 for the HIII–50M) to the AMVO specification of 

0.981 kg so as to be comparable to the THOR’s foot-within-a-molded-shoe mass. 

B. Technical Data Package 

The construction of the THOR–50M is 

similar to other ATDs currently defined 

in Part 572, with a metallic frame 

largely covered in urethane and/or vinyl 

representing flesh; body segments 

connected by translational and 

rotational joints; and deformable rubber 

or foam elements to prevent hard 

contact between metallic surfaces and to 

provide human-like impact response. 

The kinematic and dynamic 

biomechanical performance 

requirements of the THOR–50M were 

developed based on post-mortem 

human subject (PMHS) and volunteer 

response data, described in Section IV, 

Biofidelity. 

The THOR–50M that we are 

proposing in this NPRM is the version 

defined in the 2023 technical data 

package (consisting of two-dimensional 

engineering drawings and a Parts list; 

procedures for assembly, disassembly, 

and inspection (PADI); and qualification 

procedures). The 2023 technical data 

package also includes an addendum 

with the drawings and drawing/parts 

list for an alternate configuration with 

an in-dummy data acquisition system, 

as discussed in Section III.N, Data 

Acquisition System. It is anticipated 

that, upon finalization of this proposal, 


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60See Table 5. 61 In the drawings which were part of the August 

2018 technical data package, several notes state that 

‘‘qualification takes precedence over design.’’ These 

notes were unintentionally carried over from earlier 

drawing versions used during THOR–50M 

development, and have since been removed. These 

are reflected in the proposed 2023 technical data 

package. In cases where some flexibility is allowed 

in order to meet the qualification specification, a 

‘‘REF.’’ prefix is added to specific dimensions or 

material specifications. 

62This convention is used for all instruments on 

all Part 572 dummies. SA572 simply indicates that 

it is an instrument, and Sxx is the next-in-line 

number assigned by NHTSA to the instrument. 

Some load cells (and part numbers) are used on 

different Part 572 subpart dummies. For THOR, this 

applies to SA572–S4 (accelerometer) which is used 

on many other dummies. 

63Similar situations exist with currently 

federalized ATDs, such as the HIII–10C, where 

either a chest slider pot or an IR–TRACC is 

permissible. 

the in-dummy DAS drawings will be 

fully integrated within the relevant 

technical data package components. The 

technical data package is summarized in 

Table 3. For these documents, the 

NPRM cites to the document location in 

the research docket. NHTSA is not 

placing copies of these documents in 

the rulemaking docket, in order to avoid 

potential confusion from having 

identical documents docketed at 

different times in different dockets. 

However, NHTSA intends these to be 

included as part of the rulemaking 

record. A memo explaining this is also 

being included in the rulemaking 

docket. In addition, as noted in the 

background section, NHTSA began 

publishing the technical data package to 

its website starting in 2015. The 2023 

technical data package updates the 2018 

technical data package. These updates 

were made to address typographical 

errors, improve clarity, and add 

alternative design elements. Table 4 

summarizes these updates. 

TABLE 3—THOR–50M TECHNICAL DATA PACKAGE

Title Link 

THOR 50th Percentile Male with Alternate Shoulders Frontal Crash 

Test Dummy Drawings, External Dimensions, and Mass Properties.

https://www.regulations.gov/document/NHTSA-2019-0106-0013. 

*THOR–50M DAS Integration Kit Drawings, April 2023 .......................... https://www.regulations.gov/document/NHTSA-2019-0106-0019. 

*Parts List, THOR–50M DAS Integration Kit, April 2023 ......................... https://www.regulations.gov/document/NHTSA-2019-0106-0018. 

Parts List, THOR 50th Percentile Male Frontal Crash Test Dummy with 

Alternate Shoulders.

https://www.regulations.gov/document/NHTSA-2019-0106-0015. 

THOR 50th Percentile Male (THOR–50M): Procedures for Assembly, 

Disassembly, and Inspection (PADI): June 2023.

https://www.regulations.gov/document/NHTSA-2019-0106-0017. 

THOR 50th Percentile Male (THOR–50M) Qualification Procedures and 

Requirements, April 2023.

https://www.regulations.gov/document/NHTSA-2019-0106-0010. 

* The DAS Integration Kit drawings and drawing/parts list would not themselves be incorporated by reference into Part 572. It is anticipated 

that, upon finalization of this proposal, these documents will be fully integrated within the relevant technical data package components. 

TABLE 4—SUMMARY OF UPDATES MADE IN THE 2023 THOR–50M TECHNICAL DATA PACKAGE

Technical Data Package Element Revisions in 2023 Version 

Drawing Package ................................. Includes drawings for alternate shoulder, removal of notes suggesting that qualification specifications 

supersede drawing specifications, and changes to correct typographical drawing errors. Complete 

change log found in ‘‘THOR–50th Percentile Male with Alternate Shoulders (THOR–50M w/ALT. 

SHOULDERS) Drawing Revisions’’.60

PADI ..................................................... Minor typographical changes; complete change log found in Section 20 of ‘‘THOR 50th Percentile Male 

(THOR–50M) Procedures for Assembly, Disassembly, and Inspection (PADI)’’. 

Qualification Procedures ...................... Revised upper leg qualification test mode, adjusted language to be more prescriptive, removed unit 

conversions, and corrected typographical errors. Complete change log found in Appendix B of 

‘‘THOR 50th Percentile Male (THOR–50M) Qualification Procedures and Requirements, April 2023’’. 

Below we briefly discuss several 

aspects of the technical data package in 

more detail. 

Engineering Drawings and Parts List 

The engineering drawings and parts 

list specify the configuration of the 

THOR–50M. Included in the drawings 

are the required dimensions and 

tolerances, material properties, and 

component or material testing 

requirements and associated 

specifications. In a few instances, the 

drawings specify quasi-static tests and/ 

or performance requirements for 

individual parts (such as a compression 

or flexion test for a molded part or 

subassembly); however, passing a 

specified performance (or qualification) 

test is not an alternate criterion for 

accepting a part that deviates from the 

drawing specifications.61 All 

instruments are specified by 

corresponding SA572-xxx drawings.62

SA drawings are included for associated 

mounts and hardware that are not 

otherwise needed when the dummy is 

configured with a corresponding 

structural replacement. Brand name 

call-outs are only used for parts and 

materials that have widespread 

availability and are used for a wide 

variety of non-ATD applications. It 

includes materials widely identified by 

their tradenames, such as Teflon, 

Acetal, Lexan, and Nitinol. Call-outs are 

also used for bonding agents, fasteners, 

and other items that are also widely 

available for non-ATD applications. 

In some instances, the drawing 

package permits two different part or 

instrumentation configurations that are 

both fully specified. For example, the 

head accelerometer mounting plate 

assembly drawing (472–1200) calls out 

three different angular rate sensors 

(SA572–S56, SA572–S57, or SA572– 

S58) which may be desired by the end 

user depending on the implementation 

of the ATD.63 In the sections below on 

specific body regions we discuss the 

proposed as well as alternate designs 

and instrumentations that are not 

included in the proposed specifications 

but which we are considering specifying 

in the final rule and on which we are 

seeking comment. If NHTSA were to use 

the dummy for FMVSS compliance 

testing, NHTSA could test with any 

alternative configurations at its own 

discretion. Thus, the IARVs would have 


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64See, e.g., 38 FR 12934, 12935 (May 17, 1973) 

(‘‘Manufacturers should understand that they are 

not required to test their products in any particular 

manner, as long as they exercise due care that their 

products will meet the requirements when tested by 

the NHTSA under the procedures specified in the 

standard.’’). 65European New Car Assessment Programme 

(2023). THOR Specification and Certification, 

Version 1.3, available at: https://

www.euroncap.com/en/for-engineers/supportinginformation/technical-bulletins/. 

66 § 1.1. 

67 § 3.1. 

to be met using a dummy with any 

permissible configuration. 

Manufacturers are not required to test 

their products in any particular manner, 

as long as they exercise due care that 

their products will meet the 

requirements when tested by NHTSA 

under the procedures specified in the 

standard, including the relevant dummy 

specified in Part 572.64 However, a 

manufacturer would not be able to claim 

that a vehicle fully complies with a 

standard if it meets the standard’s 

requirements in only one of the 

dummy’s configurations, but not the 

other. 

In addition to the engineering 

drawings that would be incorporated by 

reference, we are also providing 

supplemental documentation on the 

form and function of the THOR–50M. 

These reference materials are 

summarized in Table 5. These files 

would not be incorporated by reference 

in Part 572 and would therefore not be 

part of the THOR–50M specification. 

Instead, they are intended only for 

reference purposes (e.g., to facilitate 

fabrication and inspection of parts with 

intricate geometries). 

TABLE 5—THOR–50M DESIGN REFERENCE DOCUMENTATION

Title Link 

THOR–50M Drawing Package—2D AutoCAD Jan 2023 ........................ https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20with%

20Alternate%20Shoulders%20Jan%202023-Auto

CAD%20DWG%20Files.zip. 

THOR–50M Drawing Package—3D Inventor Format Jan 2023 .............. https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20with%20Alternate%20Shoulders%20Jan%

202023-Inventor%20Files.zip. 

THOR–50M Drawing Package—3D STEP Format Jan 2023 ................. https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20DAS%20Integration%20Kit-3D%

20STEP%20Files_April%202023.zip. 

THOR 50th Percentile Male with Alternate Shoulders Drawing Revisions, Jan 2023.https://www.regulations.gov/document/NHTSA-2019-0106-0014. 

THOR–50M DAS Integration Kit—2D AutoCAD, April 2023 ................... https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20DAS%20Integration%20KitAutoCAD%20DWG%20Files_April%202023.zip. 

THOR–50M DAS Integration Kit—3D STEP Format, April 2023 ............ https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20DAS%20Integration%20Kit3D%20STEP%20Files_April%202023.zip. 

THOR–50M DAS Integration Kit—Inventor Format, April 2023 ............... https://static.nhtsa.gov/nhtsa/downloads/THOR_50M_Drawing_Package/NPRM/THOR-50M%20DAS%20Integration%20KitInventor%20Files_April%202023.zip. 

The THOR–50M used by Euro NCAP 

is specified in Technical Bulletin 026, 

‘‘THOR Specification and 

Certification.’’ 65 TB026 explicitly 

adopts—with some deviations—the 

2018 drawing package.66 These 

deviations in TB026 include 

specification of an onboard (in-dummy) 

data acquisition system and a variation 

to the adjustable spine to facilitate DAS 

installation; minor deviations in the 

shoulder assembly; and the use of the 

HIII–50M lower legs. These 

modifications are discussed in more 

detail in the relevant sections of the 

preamble, and are summarized in 

Section IX, Consideration of 

alternatives. Euro NCAP TB026 

specifies the 2018 drawing package, 

while this proposal specifies the 2023 

drawing package. However, given the 

differences described in Table 4 above, 

this deviation is likely to be 

inconsequential. The deviations TB026 

makes to the 2018 drawing package are 

not accompanied by engineering 

drawings, which may tend to lessen the 

dummy’s overall objectivity. Objectivity 

is a statutory necessity for ATDs in Part 

572. While the lack of accompanying 

drawings for these deviations may be 

adequate for the Euro NCAP rating 

program, it could lead to a future 

population of THOR–50M units that are 

sufficiently non-uniform as to render 

them unsuited for FMVSS applications. 

PADI 

The PADI provides step-by-step 

procedures on how to properly assemble 

the dummy. This includes instructions 

on part alignment, torque settings, wire 

routings, and other adjustments that are 

not otherwise described in the 

engineering drawings. The PADI 

provides explicit installation 

instructions for all instruments. Euro 

NCAP TB026 specifies the 2018 PADI,67

while this proposal specifies the 2023 

PADI. However, the differences between 

the 2018 PADI and 2023 PADI are 

primarily corrections to typographic 

errors, so this deviation is likely to be 

inconsequential. In some instances, the 

drawing package permits two different 

part or instrumentation configurations 

that are (or will be in the final rule) both 

fully specified (for example, the IR– 

TRACC and the S-Track for the chest 

instrumentation). The proposed PADI 

does not currently contain installation 

instructions for the optional parts (e.g. 

alternate shoulder) or instrumentation 

(e.g., the S-Track). However, where 

multiple optional configurations are 

permitted and installation differences 

are non-trivial, NHTSA anticipates 

supplementing the PADI with such 

instructions in the final rule. 

Qualification Procedures 

The qualification procedures describe 

a series of impact tests performed on a 

fully assembled dummy or subassembly. NHTSA has established 

numeric bounds or acceptance intervals 

for the ATD responses in these tests. 

The qualification procedures are 

discussed in Section V. 


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68These load cells have not been used in any tests 

currently available in NHTSA’s Vehicle or 

Biomechanics databases, and are typically replaced 

with structural replacements during testing. While 

the THOR–50M Qualification Procedure does 

include a face impact test which would exercise the 

face load cells if installed, there are currently no 

qualification specifications on face load cell forces. 69The Abbreviated Injury Scale (AIS) ranks 

individual injuries by body region on a scale of 1 

to 6: 1=minor, 

2=moderate, 3=serious, 4=severe, 5=critical, and 

6=maximum (untreatable). 70Craig, M., Parent, D., Lee, E., Rudd, R., 

Takhounts, E., Hasija, V. (2020). Injury Criteria for 

the THOR 50th Male ATD. Docket ID NHTSA– 

2019–0106–0008, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0008. 

71White RP., Zhoa Y., Rangarajan N., Haffner M., 

Eppinger R., Kleinberger M., ‘‘Development of an 

Instrumented Biofidelic Neck for the NHTSA 

Advanced Frontal Test Dummy,’’ The 15th 

International Technical Conference on the 

Enhanced Safety of Vehicles, Paper No. 96–210–W– 

19, 1996. 

72Hoofman, M., van Ratingen, M., and Wismans, 

J., ‘‘Evaluation of the Dynamic and Kinematic 

Performance of the THOR Dummy: Neck 

Performance,’’ Proceeding of the International 

Conference on the Biomechanics of Injury (IRCOBI) 

Conference, pp. 497–512, 1998. 

73Thunnissen, J., Wismans, J., Ewing, C.L., 

Thomas, D.J. (1995) Human Volunteer Head-Neck 

Response in Frontal Flexion: A New Analysis. 39th 

Stapp Car Crash Conference, SAE Paper # 952721. 

74 GESAC, Inc (2005). Users Manual: THOR 

Instrumentation Data Processing Program, Version 

2.3; Appendix C: Procedure for Calculating Head 

Loads at the Occipital Condyle from Neck Load Cell 

Measurements. National Highway Traffic Safety 

Administration. Available at: https://one.nhtsa.gov/ 

DOT/NHTSA/NVS/Biomechanics%20&

%20Trauma/THOR-NT%20Advanced%20

Crash%20Test%20Dummy/THORTEST.zip. 

75Craig, M., Parent, D., Lee, E., Rudd, R., 

Takhounts, E., Hasija, V. (2020). Injury Criteria for 

the THOR 50th Male ATD. Docket ID NHTSA– 

2019–0106–0008, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0008. 

76 Kent, R., Shaw, C.G., Lessley, D.J., Crandall, J.R. 

and Svensson, M.Y, ‘‘Comparison of Belted Hybrid 

III, THOR, and Cadaver Thoracic Responses in 

Oblique Frontal and Full Frontal Sled Tests,’’ Proc. 

SAE 2003 World Congress. Paper No. 2003–01– 

0160, 2003. 

Summary 

NHTSA believes that the technical 

data package adequately describes and 

would ensure the uniformity of the 

dummy. Upon finalization of this 

proposal, a new subpart for the THOR– 

50M would be added to Part 572, and 

the technical data package documents 

would be incorporated by reference. 

NHTSA seeks comment on whether 

the dummy is sufficiently specified to 

ensure that dummies are uniform such 

that they will provide repeatable and 

reproducible measurements. We also 

seek comment on whether it would be 

useful to end-users of the dummy if 

NHTSA created a list of suppliers used 

by NHTSA to obtain various parts and 

instrumentation, and/or general 

specifications or operating 

characteristics of a part (as provided by 

a manufacturer’s specification sheet). 

Such documentation would not be 

incorporated into Part 572 but would be 

provided as a reference aid for users and 

could be periodically updated by 

NHTSA. 

C. Head and Face 

The head of the THOR–50M is 

primarily constructed of a cast 

aluminum skull covered in a urethane 

head skin. It includes two features not 

seen on the HIII–50M: spring towers and 

a featureless face. The spring towers are 

integral to the response of the head/neck 

system, as they are the mounting 

location of the cables that represent the 

musculature of the neck (described 

further in the following section). The 

head is equipped with three uniaxial 

accelerometers and three angular rate 

sensors at the head center of gravity 

(CG) to measure translational 

acceleration and angular velocity, 

respectively. The head also includes a 

biaxial tilt sensor which measures the 

quasi-static orientation of the head for 

pre-test positioning purposes. 

The face is constructed of an opencell urethane foam sandwiched between 

the head skin and the face load 

distribution plates. The featureless face 

allows for more repeatable and 

reproducible interactions with potential 

contact surfaces and meets enhanced 

biomechanical response requirements 

which have not been implemented on 

any existing ATDs. Additionally, the 

face can be configured with five 

uniaxial load cells: left and right eye, 

left and right cheek, and chin.68

D. Neck 

The neck of the THOR–50M is visibly 

and functionally different than the 

ATDs currently defined in Part 572. 

While typical ATD designs use only a 

pin joint between the base of the head 

and the upper neck load cell, the 

THOR–50M neck is connected to the 

head via three separate load paths: two 

cables (one anterior and one posterior) 

and a pin joint between the base of the 

head and the upper neck load cell. 

These load paths are independently 

instrumented, allowing the isolation of 

forces and moments on the components 

representing bone and ligament from the 

components representing muscles. This 

is expected to allow for improved injury 

prediction for the cervical spine because 

the abbreviated injury scale (AIS) 2+ 

injuries 69 to the cervical spine in motor 

vehicle crashes are most commonly 

fractures, so the ability to measure 

forces and moments acting on the bones 

and ligaments separately from the forces 

acting through the musculature allows a 

more accurate prediction of these 

fractures.70

The biomechanical basis of the 

THOR–50M neck design is wellestablished.71 72 The construction of the 

THOR–50M neck allows the head to 

initially rotate relatively freely in the 

fore and aft directions. This allows the 

head/neck assembly to demonstrate the 

phenomenon known as head lag 

demonstrated by human volunteers in 

restrained frontal loading conditions, 

where the rotation of the head is 

delayed relative to the rotation of the 

neck.73 This phenomenon results from 

the head initially translating forward 

with respect to the base of the neck, 

which is attached to the restrained 

torso. The change in angle of the head 

initially lags the change in angle of the 

line between the head and the neck but 

catches up by the time of peak 

excursion. 

The instrumentation in the neck 

assembly includes spring load cells 

which measure the compression at the 

anterior and posterior spring locations, 

six-axis load cells at the top and base of 

the neck to measure the forces and 

moments developed at these locations, 

and a rotary potentiometer at the 

occipital condyle pin to measure the 

relative rotation between the head and 

top of the neck. Due to the multiple load 

paths of the neck, comparing THOR– 

50M neck forces and moments to 

traditional single-load-path ATD 

designs is not straightforward; the 

THOR–50M instrumentation would 

require post-processing 74 to represent 

the total neck forces and moments in 

order to compare to the upper neck load 

cell measurements of a HIII–50M ATD. 

However, as described in the THOR– 

50M Injury Criteria Report,75 postprocessing of the neck for calculation of 

neck injury risk is not necessary. 

E. Chest 

Throughout the development of the 

THOR–50M ATD, specific attention was 

given to the human-like response and 

injury prediction capability of the chest. 

Below we discuss the design and 

instrumentation of the THOR–50M 

chest. 

1. Design 

The THOR–50M’s rib cage geometry is 

more realistic than the HIII–50M 

because the individual ribs are angled 

downward to better match the human 

rib orientation.76 Biomechanical 

response requirements were selected to 

ensure human-like behavior in response 

to central chest impacts, oblique chest 

impacts, and steering rim impacts to the 


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77National Highway Traffic Safety 

Administration, ‘‘Biomechanical Response 

Requirements of the THOR NHTSA Advanced 

Frontal Dummy, Revision 2005.1,’’ Report No: 

GESAC–05–03, U.S. Department of Transportation, 

Washington, DC, March 2005. [http://

www.nhtsa.gov/DOT/NHTSA/NVS/

Biomechanics%20&%20Trauma/THORNT%20Advanced%20Crash%20Test%20Dummy/ 

thorbio05_1.pdf. 78 49 CFR 572.185(b) Individual rib drop test. 

79Morgan, R.M., Eppinger, R.H., Haffner, M.P., 

Yoganandan, N., Pintar, F.A., Sances, A., Crandall, 

J.R., Pilkey, W.D., Klopp, G.S., Kallieris, D., Miltner, 

E., Mattern, R., Kuppa, S.M., and Sharpless, C.L., 

‘‘Thoracic Trauma Assessment Formulations for 

Restrained Drivers in Simulated Frontal Impacts,’’ 

Proc. 38th Stapp Car Crash Conference, pp. 15–34. 

Society of Automotive Engineers, Warrendale, PA., 

1994. 

80 Kuppa, S., Eppinger, R., ‘‘Development of an 

Improved Thoracic Injury Criterion,’’ Proceedings 

of the 42nd Stapp Car Crash Conference, SAE No. 

983153, 1998 (data set consisting of 71 human 

subjects in various restraint systems and crash 

severities). 

81 Yoganandan, N., Pintar, F., Rinaldi, J., 

‘‘Evaluation of the RibEye Deflection Measurement 

System in the 50th Percentile Hybrid III Dummy.’’ 

National Highway Traffic Safety Administration, 

DOT HS 811 102, March 2009. 

82Parent, D., Craig, M., Ridella, S., McFadden, J., 

‘‘Thoracic Biofidelity Assessment of the THOR Mod 

Kit ATD,’’ The 23rd Enhanced Safety of Vehicles 

Conference, Paper No. 13–0327, 2013. 

83 In addition to the deflection measurement 

system, the THOR–50M can also be instrumented 

with a uniaxial sternum accelerometer, triaxial 

accelerometers installed along the spine at the level 

of T1, T6, and T12, and a five-axis (three forces, two 

moments) load cell installed between the lumbar 

spine pitch change mechanism and the lumbar 

spine flex joint at the approximate anatomical level 

of T12. Clavicle loads cells can also be installed, but 

are not included in the THOR–50M described in the 

2023 drawing package. 

rib cage and upper abdomen.77 Better 

chest anthropometry means that the 

dummy’s interaction with the restraint 

system is more representative of the 

interaction a human would experience. 

The design of the THOR–50M 

includes a part known as a rib guide 

(472–3310) which is intended to prevent 

excessive downward motion of the 

anterior thorax during an impact. The 

rib guide is attached to the shoulder, 

and when there is downward motion of 

the ribs, the bottom of the rib damping 

material on rib #1 (the superior-most rib 

in the torso, 472–3310) can contact the 

top of the rib guide. Over time, this can 

result in an indent in the rib damping 

material. This indent has been observed 

on NHTSA-owned THOR–50M ATDs, 

but it has not been a concern as this is 

a sign of the rib guide performing its 

intended function. While this indent is 

not included on the drawing package, it 

is understood that an indent is 

acceptable as long as the qualification 

specifications (specifically, those of the 

upper thorax and lower thorax) are met, 

and it is not so deep that it allows metalto-metal contact between the rib guide 

and the steel of the rib. 

While Euro NCAP TB026 adopts the 

chest specified in the 2018 drawing 

package without any modifications, 

NHTSA is aware of two potential 

changes that have been discussed. Both 

of these changes appear to be intended 

to help ensure that the dummy is able 

to meet the upper thorax qualification 

response requirements. (The TB026 

upper thorax qualification response 

requirements differ in a few ways from 

the proposed qualification 

requirements. This is discussed in more 

detail in Section V, Qualification Tests.) 

The first change that has been 

discussed is a shorter rib guide. 

Humanetics Innovative Solutions, Inc. 

(Humanetics) reported to ISO WG5 (in 

June 2020) that while the indent on the 

damping material has been a known 

issue since the THOR–NT, it has led to 

concerns because it leads to issues 

meeting the Euro NCAP upper thorax 

qualification response requirements 

(specifically, the Z-axis upper rib 

deflection requirement) on a consistent 

basis. Humanetics has therefore 

suggested the use of a new, shorter rib 

guide which would allow more Z-axis 

deflection—primarily in the upper 

thorax qualification test, but presumably 

in other impact scenarios as well. 

The second change is an additional 

rib performance specification. NHTSA 

is aware of a presentation made by the 

Japanese Automobile Manufacturers 

Association (in June 2020) to ISO WG5 

describing an additional rib 

performance specification (i.e., that 

would be specified in the drawing 

package) geared towards more 

consistently meeting the TB026 upper 

thorax qualification response 

requirements. The presentation 

included a procedure for an individual 

rib test using the same apparatus as the 

rib drop test for the ES–2re 50th 

percentile adult male side impact test 

dummy.78 It noted data showing that the 

stiffness of the individual rib in the 

drop test was correlated with the 

thoracic impact response in the upper 

thorax qualification test condition. 

NHTSA has tentatively decided not to 

implement either change. NHTSA’s 

qualification testing of the dummy did 

not reveal any issues with meeting the 

proposed upper thorax qualification 

requirements, so we do not believe such 

changes are necessary. Moreover, before 

implementing the rib guide 

modification, it could be necessary to 

evaluate whether it would influence the 

dummy’s response in biofidelity or 

thorax injury criteria test conditions. We 

do note, however, that the additional rib 

performance specification could be a 

useful way for ATD manufacturers to 

ensure that the fabricated ribs will result 

in an upper thorax qualification 

response consistent with upper thorax 

qualification specifications. 

We seek comment on these issues. In 

particular, NHTSA requests comment 

from THOR–50M users who have 

evaluated alternative rib guide designs 

and have data to support equivalence of 

durability, repeatability and 

reproducibility, and equivalence of 

response in qualification, biofidelity, 

injury criteria, and vehicle crash test 

conditions. 

2. Instrumentation 

The THOR–50M is capable of 

measuring detailed information about 

how the chest responds in a crash. 

While the HIII–50M can measure chest 

deflection at only a single point (the 

sternum), the THOR–50M measures 

chest deflections at four points. This is 

useful because thoracic trauma imparted 

to restrained occupants does not always 

occur at the same location on the rib 

cage for all occupants in all frontal 

crashes.79 Measuring deflection from 

multiple locations has been found to 

improve injury prediction,80 and can 

improve the assessment of thoracic 

loading in a vehicle environment with 

advanced occupant restraint 

technologies.81 While the HIII–50M 

measures the one-dimensional 

deflection at a single point, the THOR– 

50M can measure the three-dimensional 

position time-history for four points on 

the anterior rib cage relative to the local 

spine segment of rib origination, with 

two points on the upper chest, and two 

points on the lower chest. Between the 

upper and lower thorax instrumentation 

attachment points is a flexible joint (the 

Upper Thoracic Spine Flex Joint), so the 

reference coordinate system for the 

upper and lower thorax 3D motion 

measurements can change dynamically 

during a loading event. This 

instrumentation, coupled with its 

thoracic biofidelity,82 provides the 

THOR–50M ATD with the ability to 

better predict thoracic injuries and to 

potentially drive more appropriate 

restraint system countermeasures.83

NHTSA is proposing to specify two 

deflection measurement devices, either 

of which NHTSA could choose, at its 

option, for use in the THOR–50M: the 

IR–TRACC and the S-Track. 

IR–TRACC 

The 2023 drawing package specifies a 

specific deflection measurement device, 

the Infrared Telescoping Rod for 

Assessment of Chest Compression (IR– 


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84Rouhana, S.W., Elhagediab, A.M., Chapp, J.J. 

‘‘A high-speed sensor for measuring chest 

deflection in crash test dummies.’’ Proceedings: 

International Technical Conference on the 

Enhanced Safety of Vehicles. Vol. 1998, Paper No. 

98–S9–O–15. National Highway Traffic Safety 

Administration, 1998. 

85See SA572–S117 and SA572–S121. 

86Alliance of Automobile Manufacturers, Inc. 

(2016). Technical Considerations Concerning 

NHTSA’s Proposal to Rework the Agency’s New Car 

Assessment Program (NCAP). Regulations.gov 

Docket ID NHTSA–2015–0119–0313, available at: 

https://www.regulations.gov/contentStreamer?

documentId=NHTSA-2015-0119- 

0313&attachmentNumber=5&contentType=pdf. 

87See Figure 1 in Hagedorn, A., Murach, M., 

Millis, W., McFadden, J., Parent, D., (2019). 

Comparison of the THOR–50M IR–TRACC 

Measurement Device to an Alternative S-Track 

Measurement Device. Proceedings of the FortySeventh International Workshop on Human 

Subjects for Biomechanical Research. 

88NHTSA is placing a separate document, 

‘‘Supplemental Technical Appendices to 

Preamble,’’ in the docket for this rulemaking. 

89National Highway Traffic Safety 

Administration (2016). IR–TRACC Direct 

Replacement Sensor. Solicitation Number 

DTNH2216Q00014, available at https://sam.gov/ 

opp/d505f6119f9a31bcdfa36607ed669e6b/view. 

90Pheifer, G. (2020). U.S. Patent No. 10,713,974. 

Washington, DC: U.S. Patent and Trademark Office. 

91European New Car Assessment Program (2022). 

Euro NCAP Supplier List, Appendices I & II, 

October 2022, TB 029, available at: https://

www.euroncap.com/en/for-engineers/supportinginformation/technical-bulletins/https://

www.euroncap.com/en/for-engineers/protocols/ 

adult-occupant-protection/. 

92This evaluation of alternate thorax and 

abdomen instrumentation only considered 

replacement of the displacement transducer 

component of the 3D IR–TRACC measurement 

system. Though it was not available at the time of 

purchase, a double gimbal kit to allow 3D 

measurement is now available from the S-Track 

manufacturer. ATD-Labtech GmbH (2017). 3D 

Adaption THOR–50th upper Thorax left 20_303. 

Available at: https://www.atd-labtech.com/files/atd/ 

uploads/produkte/s-track/produkte/4%20TH-3DAdapter-Upper-Thorax-left/data_sheet-3DAdaption_Thor-50th_upper_Thorax_

left%20Rev%2001.PDF. To evaluate whether the STrack 3D adaption kit would result in equivalent 

measurement capabilities as the 3D IR–TRACC 

measurement system, the testing described here 

would be repeated, starting with the 3D static 

measurement assessment. 

93Hagedorn, A., Murach, M., Millis, W., 

McFadden, J., Parent, D., (2019). Comparison of the 

THOR–50M IR–TRACC Measurement Device to an 

Alternative S-Track Measurement Device. 

Proceedings of the Forty-Seventh International 

Workshop on Human Subjects for Biomechanical 

Research. Available at: https://wwwnrd.nhtsa.dot.gov/pdf/bio/proceedings/2019/ 

Hagdeorn_S-Track_

Biomechanics%20Workshop%202019_FINAL.pdf. 

TRACC).84 The IR–TRACC improved on 

the previous deflection measurement 

systems (CRUX—Compact Rotary Unit; 

DGSP—Double Gimbaled String 

Potentiometer) in many ways. The 2023 

drawing package specifies six IR– 

TRACCs: four in the thorax and two in 

the abdomen.85 Each IR–TRACC 

measures the absolute point-to-point 

distance along its length; this is used in 

the calculation of thorax and abdomen 

compression. The IR–TRACC is attached 

to two rotational potentiometers; this 

enables measurement of the threedimensional position of the anterior 

attachment point at the rib or front of 

the abdomen relative to the attachment 

point at the spine. 

While NHTSA has generally been 

satisfied with the performance of the 

IR–TRACC, the experience of NHTSA 

and other users with IR–TRACCequipped THOR–50Ms has revealed a 

few potential issues. Vehicle 

manufacturers have raised several 

concerns about the performance and 

durability of the IR–TRACC, such as 

having to frequently repair or replace 

IR–TRACCs, and problems with the 

abdomen IR–TRACCs.86 And during 

NHTSA-sponsored testing (particularly 

in the frontal oblique crash test mode), 

NHTSA observed abrupt decreases in 

the IR–TRACC voltage time-history.87

We believe this is noise (and not a 

signal) because it occurs in all IR– 

TRACC voltage channels of a single 

ATD at the same points in time. As 

explained later in this document 

(Section VII.B.2) and in Appendix F to 

the preamble,88 NHTSA testing has 

shown that once the IR–TRACC voltage 

signal is linearized, scaled, filtered, and 

converted to three-dimensional 

deflection, this noise is no longer 

evident. Nonetheless, this presents a 

risk of perceived or actual inaccuracies 

in thoracic and abdominal injury 

prediction during crash tests. 

S-Track

In 2016 NHTSA issued a request for

proposals for commercially-available 

devices capable of measuring the same 

or greater deflection range (roughly 90 

millimeters of deflection for the thorax 

and 120 millimeters of deflection for the 

abdomen) within the same packaging 

space as the existing IR–TRACC 

devices.89 Only one device—the STrack—was identified. The S-Track, 

which is patented,90 is produced by 

ATD-LabTech GmbH. (In 2022, 

Humanetics acquired ATD-LabTech.) 

Subsequent to the request for proposal, 

NHTSA also became aware of two 

additional deflection measurement 

devices: the KIR–TRACC, sold by Kistler 

Group, and the Spiral Track, sold by 

JASTI. NHTSA does not know whether 

these devices are congruent with the 

current THOR–50M parts and SAdrawings that describe the configuration 

and installation of IR–TRACCs. Because 

NHTSA became aware of these devices 

late in the development process (and 

neither was identified in NHTSA’s 

request for proposals), they have not 

been considered for inclusion in the 

proposal, although NHTSA is 

considering evaluating whether they 

would be suitable instrumentation for 

the THOR–50M. Euro NCAP allows for 

installation of the IR–TRACC, the STrack, and the KIR–TRACC.91

The S-Track is similar to the IR– 

TRACC in that it is in-dummy 

instrumentation that attaches to the 

same points in the dummy as the IR– 

TRACC. Both measure linear 

displacement, and when coupled with 

the gimballed potentiometers, their 

signals can be post-processed to 

calculate three-dimensional motion. It 

differs in that the S-Track uses a 

mechanical scissor mechanism coupled 

to a linear potentiometer to measure 

linear motion along its axis, while the 

IR–TRACC uses a measurement of light 

transmittance, which requires a 

linearization calculation to estimate 

linear motion. 

NHTSA has conducted a range of 

testing to evaluate the performance and 

equivalence of the S-Track. The testing, 

which included a partial qualification 

test series and sled tests, is briefly 

summarized below.92 A more detailed 

discussion of this material is available 

in a previously published paper (except, 

as noted below, the second set of sled 

tests, for which a report is 

forthcoming).93

• The range and linearity of the STrack and IR–TRACC sensors are 

comparable. The range of measurement 

of the S-Track is consistent with or 

larger than the range of measurement of 

the IR–TRACC, and all sensors were 

within the manufacturer’s specification 

for the maximum allowable linear error 

as a percentage of full scale. This 

specification (0.5%) is tighter compared 

to the corresponding IR–TRACC 

specification (2%), though only one of 

the IR–TRACCs (right abdomen) showed 

a linearity error greater than 0.5%. 

• Calibration and 3D static

measurement assessments demonstrated 

similar or better accuracy compared to 

the IR–TRACC in the double-gimbal 

configuration for the upper left thorax, 

lower left thorax, and left abdomen. In 

the upper and lower thorax 

configurations, the S-Track showed less 

error than the IR–TRACC, and in the 

abdomen configuration, showed errors 

similar to the IR–TRACC. 

• The form, fit, and function is

comparable to the IR–TRACC. A full set 

of six S-Tracks was installed in a 

THOR–50M ATD. It did not present any 

connectivity or interference issues and 

appeared to be a plug-and-play 

replacement to the IR–TRACCs. One 

possible durability issue was identified 


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94Additional evaluation would be desirable in 

cases where abdominal deflection is a critical 

measurement, such as a rear seat environment 

where submarining may be more likely to occur. 

95The Gold Standard 1 test uses a flat rigid seat, 

standard lap and shoulder belts, knees restrained, 

and right front passenger restraint geometry. The 

Gold Standard 2 test uses a flat rigid seat, a forcelimited shoulder belt and standard lap belt, knees 

restrained, and right front passenger restraint 

geometry. 

96To ̈rnvall, F.V., Holmqvist, K., Davidsson, J., 

Svensson, M.Y., Ha ̊land, Y., O ̈ hrn, H., ‘‘A New 

THOR Shoulder Design: A Comparison with 

Volunteers, the Hybrid III, and THOR NT,’’ Traffic 

Injury Prevention, 8:2, 205–215, 2007. 

97Shaw, G., Parent, D., Purtsezov, S., Lessley, D., 

Crandall, J., Tornvall, F., ‘‘Torso Deformation in 

Frontal Sled Tests: Comparison Between THOR– 

NT, THOR–NT with the Chalmers SD–1 Shoulder, 

and PMHS,’’ Proceedings of the International 

IRCOBI Conference, 2010. 

(damage to the cable at the base of the 

S-Track). This issue is mitigated if cable 

routing documentation is followed or 

the S-Track-specific double-gimbal 

assembly is used. 

• The S-Track performed equivalently 

in qualification tests. NHTSA carried 

out the qualification tests for the body 

regions expected to be sensitive to a 

difference in thorax and abdomen 

instrumentation (upper thorax, lower 

thorax, and abdomen) on a THOR–50M 

in two different configurations: a 

baseline configuration with IR–TRACCs 

in all locations, and an alternate 

configuration with S-Tracks in all 

locations. Both configurations met the 

qualification targets for all of the test 

modes specified for those body regions, 

which demonstrates that the difference 

in measured deflections between the STrack and IR–TRACC were well within 

expected test-to-test variation. In 

addition, the deflection time-history 

was qualitatively similar to the IR– 

TRACC. 

• The S-Track performed equivalently 

to the IR–TRACC in most respects in a 

series of sled tests. NHTSA conducted 

sled tests in several conditions with the 

THOR–50M in two configurations: one 

with the IR–TRACC in all locations, and 

one with the S-Track in all locations: 

Æ The first series used a reinforced 

buck representative of the front half of 

a mid-sized passenger vehicle 

(including seat belt, frontal air bag, and 

side curtain air bag) and simulated a 

near-side frontal oblique (20 degrees) 

crash. The crash pulse was based on a 

frontal oblique crash test of the same 

vehicle. The S-Track proved to be 

durable and did not demonstrate the 

same noise artifacts as the IR–TRACC. 

The S-Tracks in the thorax showed 

similar measurements as the IR– 

TRACCs, particularly in the upper right 

thorax, the closest measurement 

location to the shoulder belt. There were 

some potential differences between the 

abdomen measurements, but abdominal 

deflection is not currently included as 

an injury criterion in FMVSS No. 208 

and is not currently included in the 

rating calculation for frontal NCAP.94

Æ The second series of sled tests were 

conducted in the Gold Standard 1 (40 

km/h, 12g peak pulse, standard lap and 

shoulder belt) and Gold Standard 2 

(30km/h, 9g peak pulse, 3kN load 

limited shoulder belt) test conditions, 

which were used both in biofidelity 

assessment and in the development of 

thoracic injury criteria.95 The goal of 

this testing was to determine if any 

differences occurred between the IR– 

TRACC and S-Track measurement 

devices, and if so, whether the 

magnitude of these differences would 

affect the biofidelity and injury criteria 

development analyses. NHTSA is 

preparing a report on this second series 

of sled tests, which will be placed in the 

research docket when it is complete. 

Based on this testing and analysis, 

NHTSA believes that the S-Track is 

equivalent to the IR–TRACC (with the 

potential exception of the abdomen 

deflection in a sled test environment). 

Proposal 

NHTSA proposes to specify both the 

IR–TRACC and the S-track as 

permissible instrumentation for the 

THOR–50M. A THOR–50M configured 

with all IR–TRACCs or all S-tracks 

would conform to Part 572 and NHTSA 

could perform compliance testing with 

either device installed in the THOR– 

50M. The dummy has not been tested in 

a mixed configuration, with both 

devices installed (e.g., IR–TRACCS in 

the chest and S-Tracks the abdomen, or 

with one IR–TRACC and three S-Tracks 

in the chest). The overall effects of such 

configurations are unknown. NHTSA 

seeks comment on whether the final 

specifications should allow such 

configurations. The IR–TRACC is 

specified in the 2023 drawing package 

(in SA572–S117 and SA572–S121). 

NHTSA has not yet published 

engineering drawings and parts 

packages to specify how the S-Track is 

installed in the dummy, but intends to 

integrate such documentation into the 

associated technical data package 

components upon finalization of this 

proposal. NHTSA seeks comment on 

this proposal. 

F. Shoulder 

The THOR–50M shoulder was 

developed to allow a human-like range 

of motion and includes a clavicle 

linkage intended to better represent the 

human shoulder interaction with 

shoulder belt restraints.96 Clavicle load 

cells that can be installed in the 

proximal and distal ends of the clavicles 

are commercially available, but these 

load cells are not currently defined in 

the drawing package and NHTSA has 

not evaluated them. 

Below we discuss shoulder 

components for which NHTSA is 

proposing alternative permissible 

specifications (the alternate shoulder) or 

for which design modifications have 

been developed by external THOR–50M 

users but which NHTSA has tentatively 

decided not to incorporate in the 

drawing package (shoulder slip and 

coracoid process). 

1. Alternate Shoulder Specification 

Portions of the shoulder assembly 

specified in the 2018 drawing package 

(referred to as the SD–3 shoulder) are 

covered by a patent issued to 

Humanetics. However, for the reasons 

discussed in more detail in Section VIII, 

NHTSA has generally avoided 

specifying in Part 572 patented 

components or copyrighted designs 

without either securing agreement from 

the rights-holder for the free use of the 

item or to license it on reasonable terms 

or developing an alternative 

unencumbered by any rights claims. 

NHTSA has therefore designed, built, 

and tested an alternative design for a 

part of the shoulder assembly referred to 

as the shoulder pivot assembly that is 

not subject to any intellectual property 

claims. Accordingly, the proposed 

drawing package (the 2023 drawing 

package) includes specifications for the 

SD–3 shoulder pivot assembly as well as 

the alternate shoulder pivot assembly, 

so that either may be used. We explain 

this in more detail below. 

SD–3 Shoulder 

The SD–3 shoulder is notably 

different from the shoulder specified for 

the THOR–NT. The THOR–NT design 

includes a clavicle linkage attached by 

ball joints at the sternum and acromion, 

a linkage between the acromion and the 

scapula to which the upper arm 

attaches, and a linkage representing the 

scapula that attaches to the acromion 

linkage and the spine with 

unconstrained revolute joints. While 

there were some benefits of the THOR– 

NT design compared to existing ATDs at 

the time, the range of motion of the 

THOR–NT shoulder was found to be 

lacking compared to the human 

shoulder.97

An improved shoulder design was 

independently initiated by the Chalmers 

University of Technology (Chalmers), in 


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98To ̈rnvall et al. (2007), 205–215. 

99Shaw et al (2010). 

100Crandall, J. (2013). ATD Thoracic Response: 

Effect of Shoulder Configuration on Thoracic 

Deflection. NHTSA Biomechanics Database, Report 

b11017R001, available at: https://www-nrd.nhtsa.

dot.gov/database/MEDIA/GetMedia.aspx?

tstno=11017&index=1&database=B&type=R. 

101Lemmen, P., Been, B., Carroll, J., Hynd, D., 

Davidsson, J., Song, E., and Lecuyer, E. (2012). 

Development of an advanced frontal dummy thorax 

demonstrator. Proceedings of the 2012 IRCOBI 

Conference, Paper No. IRC–12–87, September 2012. 

102Crandall, J. (2013). ATD Thoracic Response: 

SD3 Shoulder Evaluation. NHTSA Biomechanics 

Database, Report b11470R001, available at: https:// 

www-nrd.nhtsa.dot.gov/database/MEDIA/GetMedia.

aspx?tstno=11470&index=1&database=B&type=R. 

103Parent, D., Craig, M., Ridella, S., McFadden, J., 

‘‘Thoracic Biofidelity Assessment of the THOR Mod 

Kit ATD,’’ The 23rd Enhanced Safety of Vehicles 

Conference, Paper No. 13–0327, 2013. 

104National Highway Traffic Safety 

Administration (2014). THOR 50th Percentile Male 

Drawing Package, September 2014. available at: 

https://www.nhtsa.gov/DOT/NHTSA/NVS/ 

Biomechanics%20&%20Trauma/

THOR%20Advanced%20

Crash%20Test%20Dummy/thoradv/THOR-M_PDF_

2014-09-29.pdf. 

105Been, B., & Burleigh, M. (2017). U.S. Patent 

No. 9,799,234. Washington, DC: U.S. Patent and 

Trademark Office. 

a project sponsored by Volvo and 

Autoliv, that sought to improve the 

prediction of occupant response in 

offset and oblique frontal crashes. 

Several prototype shoulder assemblies 

were constructed and evaluated, the 

most promising being labeled the 

Shoulder Design 1 (SD–1).98 The SD–1 

shoulder design includes a clavicle 

linkage with human-like geometry, 

connected by cardan joints to the 

sternum and acromion; a linkage 

representing the scapula that includes 

attachment to the upper arm; and a twopart linkage connecting the scapula to 

the spine which allows both upward 

and anterior motion of the shoulder 

assembly. The anterior rotation of the 

scapula linkage about a vertical shaft is 

governed by a coil spring within an 

assembly mounted to the spine box. 

Several rotation stops are installed 

throughout the assembly to prevent 

metal-to-metal contact at the extents of 

the range-of-motion. 

After evaluation of the SD–1 in 

dynamic sled testing in comparison to 

the standard THOR–NT shoulder and to 

PMHS,99 several improvements were 

proposed, including durability 

improvements to the humerus joint, 

decreasing the range of motion in the 

anterior and superior directions, and 

increasing the range of motion in the 

posterior and medial directions. The 

improved design, labelled as the SD–2 

shoulder, was fabricated by GESAC to 

Chalmers’ specifications, installed on a 

THOR–50M ATD, and evaluated in sled 

tests in the Gold Standard 1 and Gold 

Standard 2 conditions at the University 

of Virginia.100 Several additional 

durability and usability concerns were 

raised upon post-test inspection, 

including deformation of the joint 

between the clavicle and the acromion 

and hard contact to the humerus joint. 

Subsequently, an updated version of 

the SD–2 shoulder, known as the SD–3, 

was designed and fabricated as part of 

the European Union’s Thoracic Injury 

Assessment for Improved Vehicle Safety 

(THORAX) project.101 Changes 

introduced in the SD–3 design included 

redesigned sterno-clavicular joint 

anthropometry, an updated shoulder 

cover, and improvements intended to 

address the durability and usability 

concerns raised by the University of 

Virginia testing. These latter 

improvements consisted of replacing the 

clavicle U-joint with a spherical joint; 

replacing the humerus joint with a 

metric version of the HIII–50M upper 

arm joint; and introducing a series of 

washers and bushings to the bottom of 

the vertical shaft to enable the resistance 

of the assembly to be adjusted to allow 

a more reproducible initial position. 

The SD–3 shoulder was installed on 

a THOR–50M ATD and sled testing was 

again carried out at the University of 

Virginia in the Gold Standard 1 and 

Gold Standard 2 conditions, as well as 

a variation of Gold Standard 1 with a 

force-limited belt.102 The SD–3 shoulder 

assembly was inspected in detail 

throughout this testing, and no evidence 

of damage was identified. The chest 

deflection and torso motion was similar 

to the SD–1 and SD–2 shoulders, while 

durability was improved. NHTSA also 

conducted an evaluation of blunt 

thoracic impact response of several 

configurations of THOR–50M ATDs and 

found the iteration with the SD–3 

shoulder assembly installed to have the 

highest qualitative and quantitative 

biofidelity.103 Given these findings, 

NHTSA modified the drawing package 

to include the SD–3 shoulder. The first 

iteration of the drawing package to 

include the SD–3 shoulder was 

published as the September 2014 

version.104

After the publication of the September 

2014 drawing package, Humanetics filed 

an application for a patent describing a 

shoulder assembly as well as an upper 

arm with an integrated load cell.105

Similar to the SD–3 shoulder, the design 

patent describes a shoulder pivot 

assembly which includes, among other 

things, a coil spring and an adjustable 

resistance element. After discussions 

between NHTSA and Humanetics, a 

disclaimer stating that portions of the 

THOR–50M drawings were covered by a 

Humanetics patent was added first to 

the NHTSA website where the drawings 

were available for download, and later 

to the drawings for the shoulder and 

upper arm assemblies in the drawing 

package itself. 

NHTSA has generally avoided 

specifying such parts, consistent with 

the legislative history of the Safety Act. 

(See Section VIII, Intellectual Property.) 

For this reason, as explained below we 

are also proposing, in addition to the 

SD–3 shoulder, an alternative shoulder 

pivot assembly design. 

Alternate Shoulder Pivot Assembly 

Design 

To address the potential issues with 

specifying only a proprietary shoulder 

design, NHTSA has designed, built, and 

tested an alternate shoulder pivot 

assembly that is not subject to any 

intellectual property claims. The 

alternate shoulder pivot assembly does 

not include any components to adjust 

the resistance of the assembly, and does 

not use a coil, clock, or watch-spring 

mechanism. Instead, the alternate 

shoulder pivot assembly design uses a 

molded rubber cylinder acting as a 

torsion bar. The top of the cylinder is 

attached to the shoulder support 

assembly and the bottom is attached to 

the spring housing, so rotation of the 

shoulder about the local Z-axis of the 

ATD results in torsion of the rubber 

cylinder. In order to adjust the 

resistance of the assembly, the springs 

must be removed and replaced. 

NHTSA has evaluated the alternate 

shoulder in a variety of tests and 

tentatively concludes that its 

performance is similar to the SD–3 

shoulder based on testing carried out to 

date. This testing, which included a 

partial qualification test series and sled 

tests, is briefly summarized below. A 

more detailed discussion of this 

material is available in a testing report 

that NHTSA is preparing, and which 

will be placed in the research docket 

when it is completed. NHTSA is also 

preparing another report that describes 

additional sled testing that was 

conducted; this report will be placed in 

the research docket when it is complete. 

First, the alternate shoulder was 

installed in a THOR–50M without any 

issues regarding the form, fit, or 

function. Second, in a quasi-static 

rotation test, the alternate shoulder 

showed a similar moment-rotation 

loading slope to the SD–3 shoulder in 

both the forward and rearward rotation 

directions. Third, the SD–3 and 

alternate shoulder showed nearly 

identical longitudinal motion in all 

three loading directions in a quasi-static 

biofidelity evaluation comparing each 


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106Tylko, S., Tang, K., Giguere, F., Bussieres, A. 

(2018). Effects of Shoulder-belt Slip on the Kinetics 

and Kinematics of THOR. Proceedings of the 2018 

IRCOBI Conference. 

107Wang, Z.J., Fu, S., McInnis, J., Arthur, J. 

(2019). Evaluation of Novel Designs to Address the 

Shoulder-belt Entrapment for THOR–50M ATD. 

Proceedings of the 2019 IRCOBI Conference. 

108 Drawing 472–6900–1/2. 

109Haffner, M., Rangarajan, N., Artis, M., Beach, 

D., Eppinger, R., Shams, T. (2001). Foundations and 

Elements of the NHTSA THOR Alpha ATD Design. 

The 17th International Technical Conference for the 

Enhanced Safety of Vehicles, Paper No. 458. 

shoulder’s range of motion to that of 

human volunteers; the responses of both 

were generally similar to the human 

volunteer response corridors. Fourth, 

the qualification tests most likely to be 

affected by shoulder response (upper 

thorax and chest) were carried out; the 

THOR–50M with the alternate shoulder 

met all qualification specifications for 

the upper thorax, and the forcedeflection characteristic of the chest was 

nearly identical to that of a THOR–50M 

with the SD–3 shoulder. Finally, sled 

tests conducted in both a full frontal 

and a far-side oblique condition did not 

reveal any durability or usability issues, 

and the response of the THOR–50M 

with the alternate shoulder was within 

the test-to-test variation of the THOR– 

50M with the SD–3 shoulder. 

NHTSA is therefore proposing the 

alternative shoulder as an acceptable 

optional subassembly. The shoulder 

assemblies are specified on drawings 

472–3810 (left) and 472–3840 (right). 

Each shoulder assembly drawing 

specifies that either the SD–3 shoulder 

pivot assembly or the alternate shoulder 

pivot assembly may be used. The 

proposed specifications for the SD–3 

shoulder pivot assembly are provided in 

drawings 472–3811 and 472–3841, and 

the proposed specifications for the 

alternate shoulder pivot assembly are 

provided in drawings 472–6810–1 and 

472–6810–2. The drawing package 

currently indicates that the selection of 

which shoulder pivot assembly to use is 

made separately for the left and right 

shoulder assemblies, so that the dummy 

could be fitted with the SD–3 shoulder 

pivot assembly on one side, and the 

alternate shoulder pivot assembly on the 

other side. The dummy has not been 

tested in such a mixed configuration, 

and the overall effects of such 

configurations are unknown. NHTSA 

seeks comment on whether the final 

specifications should allow such mixed 

configurations. 

NHTSA seeks comment on whether 

the final drawing package should 

include the SD3 shoulder, the alternate 

shoulder, or both. NHTSA also seeks 

comment from THOR–50M users who 

have evaluated the proposed alternate 

shoulder design, or other alternate 

shoulder designs, and have data related 

to equivalence with respect to 

durability, repeatability and 

reproducibility, and response in 

qualification, biofidelity, injury and 

vehicle crash test conditions. 

2. Shoulder Slip 

NHTSA is aware that some 

researchers and regulatory authorities 

have identified what they view as a 

possible design flaw in the shoulder— 

that the shoulder belt may slip towards 

the neck in a crash—and have 

developed potential modifications to the 

shoulder design to prevent this from 

happening. 

This concern was first raised in a 

2018 conference paper describing 

research conducted by Transport 

Canada. Transport Canada conducted a 

series of vehicle crash tests with the 

THOR–50M in the driver seat in two 

conditions: 40% offset and full frontal 

rigid barrier.106 It was reported that the 

upper portion of the shoulder belt could 

translate towards the neck and become 

entrapped in the gap between the neck 

and the shoulder. This occurred in 33 of 

the 45 offset tests and in 2 of the 13 full 

frontal rigid barrier tests. Compared to 

tests without shoulder belt slip, tests 

with shoulder belt slip showed higher 

measurements for lower neck shear (Xaxis and Y-axis force), higher chest 

deflections in the upper left and lower 

right quadrants, and lower clavicle axial 

forces. 

Following that research, a 2019 

Humanetics study identified and 

evaluated three prototype alternative 

modifications to the shoulder specified 

in the 2018 drawing package to prevent 

the shoulder belt from entering the gap 

between the neck and the shoulder.107

The study concluded that all three 

prototype modifications prevented belt 

entrapment and identified the preferred 

design alternative (referred to as a 

profiled split design). While the 

shoulder specified by NHTSA uses the 

same material for the entire shoulder 

pad, the profiled split design replaces 

the material closest to the neck with a 

higher-stiffness plastic material. This is 

intended to prevent the collar (the 

portion of the shoulder pad closest to 

the neck) from deforming and allowing 

the shoulder belt to slip towards the 

neck. 

In addition, in recent discussions 

with NHTSA, Euro NCAP has noted that 

several instances of shoulder belt 

slippage were observed in Euro NCAP 

testing as well as research tests with the 

mobile progressive deformable barrier. 

Euro NCAP reported that it was 

evaluating two potential shoulder 

design modifications, and expected 

these to be presented for approval in 

2023. 

While NHTSA has witnessed the 

shoulder belt moving towards the neck 

in vehicle crash tests, this phenomenon 

does not appear to influence dummy 

measurements related to injury criteria. 

NHTSA seeks comment on the 

desirability of and specifications for a 

modification to prevent belt slippage, 

including data on testing with the 

proposed shoulder design showing that 

it is leading to belt slippage that has a 

meaningful effect on test results. 

NHTSA also requests comment from 

THOR–50M users who have evaluated 

the split shoulder pad (or any available 

alternatives) and have data to support 

equivalence of durability, repeatability 

and reproducibility, and response in 

qualification, biofidelity, injury criteria, 

and vehicle crash test conditions. 

G. Hands 

The THOR–50M specified in the 2023 

drawing package includes the same 

hand design as the HIII–50M. The 

drawing defining the hand assembly of 

the THOR–50M 108 includes material 

formulation (Solid Vinyl, Formulation 

Portland Plastics, PM–7003) along with 

two two-dimensional images and one 

three-dimensional image of the hand. 

Additionally, the three-dimensional 

geometry of the hand assembly is 

included in the computer-aided design 

(CAD) files available through the 

NHTSA website in both Autodesk 

Inventor and generic STEP formats. 

However, the vinyl call-out does not 

sufficiently specify the hardness or the 

stiffness of the material formulation and 

may be insufficient to define the part. 

NHTSA therefore seeks comment on 

whether there is a need for a material 

test (e.g., hardness measurement or a 

quasi-static compression test of a 

coupon of the material) or performance 

test (e.g., quasi-static or dynamic impact 

to the as-fabricated hand) to further 

define the hand assembly of the THOR– 

50M, and if so, what the test might be. 

H. Spine 

The spine of the THOR–50M ATD is 

primarily constructed of steel. There are 

two flexible elements (one in the 

thoracic spine and one in the lumbar 

spine) that are intended to allow 

human-like spinal kinematics in both 

frontal and oblique loading 

conditions.109 Between the two flexible 

elements is a posture adjustment joint 

known as the lumbar spine pitch change 

mechanism, which allows the posture of 

the THOR–50M to be adjusted into 

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110See Fig. 5–32 in the PADI. 

111 § 1.4.3. 

112Reynolds, H., Snow, C., Young, J., ‘‘Spatial 

Geometry of the Human Pelvis,’’ U.S. Department 

of Transportation, Technical Report No. FAA–AM– 

82–9, 1982. 

113Haffner, M., Rangarajan, N., Artis, M., Beach, 

D., Eppinger, R., Shams, T., ‘‘Foundations and 

Elements of the NHTSA THOR Alpha ATD Design,’’ 

The 17th International Technical Conference for the 

Enhanced Safety of Vehicles, Paper No. 458, 2001. 

114Shams, T., Rangarajan, N., McDonald, J., 

Wang, Y., Platten, G., Spade, C., Pope, P., Haffner, 

M., ‘‘Development of THOR NT: Enhancement of 

THOR Alpha—the NHTSA Advanced Frontal 

Dummy,’’ The 19th International Technical 

Conference for the Enhanced Safety of Vehicles, 

Paper No. 05–0455, 2005. 

degree increments, including, but not 

limited to, four designated positions 

(erect, neutral, slouched, and super 

slouched).110 The spine is instrumented 

with a five-axis thoracic spine load cell 

mounted below the lumbar spine pitch 

change mechanism and above the 

lumbar spine flex joint (a flexible joint 

that allows the dummy to go into 

flexion/extension in the lumbar region). 

Triaxial accelerometers can be installed 

in the nominal locations of the first, 

sixth, and twelfth thoracic vertebra. 

The proposed spine design differs 

from the THOR–50M used by Euro 

NCAP. Whereas the 2023 drawing 

package specifies a lumbar spine pitch 

change mechanism, TB026 specifies a 

four-position lumbar spine box or an 

‘‘alternative spine box’’ if ‘‘data has 

been provided to show equivalence 

between the NHTSA spine assembly 

and modified spine assembly.’’ 111

Humanetics holds a patent on the fourposition spine. The four-position 

lumbar spine is not specified further, 

but it does differ from the spine 

specified by the NHTSA drawings. The 

spine pitch change mechanism specified 

in the 2023 drawing package allows the 

spine to be set at a multitude of flexion 

or extension settings, not just four. 

NHTSA understands that the Euro 

NCAP design is intended to 

accommodate the in-dummy installation 

of some DAS brands by providing a 

mounting surface for data loggers. 

THOR–50M units built for Euro NCAP 

are configured with in-dummy DAS 

systems have the four-position spine. 

NHTSA has tentatively decided not to 

specify a lumbar spine pitch change 

mechanism limited to four positions for 

a few reasons. First, NHTSA has not 

inspected, nor has it performed any 

testing with, the four-position spine. 

Second, NHTSA generally avoids 

specifying patented components in Part 

572 (see Section VIII, Intellectual 

Property). Third, the proposed spine 

specifications provide more 

adjustability than the four-position 

spine so the dummy may be used in a 

wider range of applications. NHTSA 

seeks comment on user experience with 

the four-position spine, including any 

data on equivalence with the THOR– 

50M as specified in the 2023 drawing 

package or biofidelity. 

It is also NHTSA’s understanding that 

members of Working Group 5 have 

observed variations in the ATD 

responses in the upper thorax 

qualification tests that have led to 

difficulties in meeting the Euro NCAP 

qualification specifications. Some 

manufacturers have suggested that this 

variation in response is due to variation 

in the spine flex joint (specifically, the 

vertical displacement (Z-axis) of the ribs 

is too high). One potential cause that 

has been identified (by Porsche in 

November 2019) is that that the 

hardness of the material comprising the 

spine flex joint was lower than the 

specification called for. 

NHTSA’s qualification testing did not 

reveal any issues with meeting the 

upper thorax qualification specifications 

(See Section V.D). In any case, in light 

of the potential concerns raised within 

Working Group 5 of possible excessive 

variation in the performance of the 

spine flex joint, potentially traceable to 

out-of-specification materials, NHTSA 

conducted a limited modeling exercise 

using the THOR–50M Finite Element 

(FE) model to investigate this. This 

analysis suggested that while variation 

in the lumbar and thoracic spine flex 

joints does influence the thoracic 

response in both qualification and sled 

test conditions, this variation is smaller 

than the expected test-to-test and ATDto-ATD variation; specifically, a 

decrease in stiffness of the spine flex 

joints can influence the upper thorax 

qualification response, but by a much 

smaller magnitude than the width of the 

qualification specifications and test-totest and ATD-to-ATD variations. For 

more information on this issue and 

NHTSA’s FE modelling, please see 

Appendix B. 

Nonetheless, a research effort is 

currently underway to assess the 

influence of the lumbar and thoracic 

spine flex joints in physical 

qualification tests (which would 

provide additional validation data to the 

computational analysis) and develop 

isolated dynamic tests of the lumbar and 

thoracic spine flex joints. Based on 

these results, NHTSA could potentially 

consider adding such a test(s) in the 

drawing package, qualification 

procedures, or laboratory test 

procedures. NHTSA requests comment 

from THOR–50M ATD users who have 

data to demonstrate variation in THOR– 

50M response that is believed to result 

from spine flex joint variation, 

specifically when the parts evaluated 

met the specifications of the THOR– 

50M drawing package. Additionally, 

NHTSA requests comment on the need 

for a thoracic spine and/or lumbar spine 

flex joint specification beyond the 

geometry and material properties 

defined in the drawing package. 

I. Abdomen 

The abdomen of the THOR–50M 

consists of two components, the upper 

abdomen and the lower abdomen. The 

lower abdomen is the region between 

the lower thoracic rib cage and the 

pelvis. The upper abdomen is the region 

on the dummy that represents the lower 

thoracic cavity, which fills the volume 

that exists between the lowest three ribs, 

above the lower abdomen and in front 

of the spine. The upper and lower 

abdomen components of THOR–50M 

are represented by structural fabric bags 

containing foam inserts which define 

the compression stiffness. Both 

abdomen inserts are anchored 

posteriorly to the spine, while the upper 

abdomen insert is additionally anchored 

to the lower rib cage. When the lumbar 

spine pitch change joint is set to the 

‘‘slouched’’ position, the abdomen 

inserts are in contact with one another; 

when in the ‘‘erect’’ and ‘‘neutral’’ 

positions, the gap between the 

abdominal inserts is filled with the 

lower abdomen neutral/erect position 

foam. This gap is also spanned by two 

steel stiffeners on each side that are 

installed into the torso jacket. The 

bottom surface of the lower abdomen 

insert is coincident with the pelvis. 

J. Pelvis 

The THOR–50M pelvis is designed to 

represent human pelvis bone structure 

to better represent lap belt 

interaction,112 113 and the pelvis flesh is 

designed to represent uncompressed 

geometry to allow human-like 

interaction of the pelvis flesh with the 

vehicle seat.114 The pelvis assembly is 

constructed of a steel and aluminum 

structure representing bone surrounded 

by a molded foam-filled vinyl covering 

representing flesh. The flesh is not 

physically connected to the pelvis bone 

but is held in place due to the tight fit 

of protrusions of the pelvis bone into 

recesses in the pelvis flesh, as well as 

circular bosses in the pelvis flesh into 

recesses in the pelvis bone. The pelvis 

flesh includes a portion of the upper 

thigh flesh, the interior surface of which 

includes gaps around the femur bone to 

allow articulation of the leg about the 

hip joint. 

The THOR–50M pelvis flesh is a 

molded component, with a vinyl outer 


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115 Drawing 472–4100. 116White Jr, R.P., Rangarajan, N., Haffner, M., 

‘‘Development of the THOR Advanced Frontal 

Crash Test Dummy’’, 34th Annual SAFE 

Symposium, Conference paper, 1996. 

117Ridella, S., Parent, D., ‘‘Modifications to 

Improve the Durability, Usability, and Biofidelity of 

the THOR–NT Dummy,’’ The 22nd International 

Technical Conference for the Enhanced Safety of 

Vehicles, Paper No. 11–0312, 2011. See Figure 17. 

118 Id. at Figure 16. 

119 Id. 

120See Biofidelity Report, p. 254 (Fig. 45). 

121National Highway Traffic Safety 

Administration (2016). Parts List and Drawings 

THOR–50M Advanced Frontal Crash Test Dummy 

THOR–50M Male August 2016. Docket ID NHTSA– 

2015–0119–0376. 

122Specification is not stated in Euro NCAP 

TB026, but believed to be MIL–S–13192P as 

specified in 49 CFR 571.208 S8.1.8.2. 

layer filled with expandable 

polyurethane foam. The twodimensional drawing includes top, side, 

front, and isometric views of the molded 

pelvis flesh, while its three-dimensional 

geometry is included in the CAD files 

available through the NHTSA website in 

both Autodesk Inventor and generic 

STEP formats. The drawing package 

specifies part weight and foam 

density 115 but not a material response 

or performance requirement for the 

pelvis flesh. 

NHTSA is considering adding a 

performance specification for the pelvis 

flesh similar to that defined in the HIII– 

50M PADI. Such a performance 

specification would dictate the amount 

of allowable compression of the pelvis 

flesh under a defined load. A similar 

test was conducted on the pelvis flesh 

during the THOR Alpha design 

development.116 One such possible 

requirement would be the compression 

at a force of 500 N. Alternatively, 

Porsche has suggested a dynamic impact 

test using an impactor similar to that 

used in the upper thorax qualification 

test to impact the bottom of the pelvis 

flesh at a velocity of 2 m/s. NHTSA 

seeks comment on the need and 

specifications for a pelvis compression 

test, including whether it should be a 

qualification requirement, a drawing 

specification, or otherwise. 

The pelvis is instrumented with bilateral triaxial load cells attached to the 

acetabulum (in order to measure the 

reaction force between the femur and 

the pelvis) and a triaxial accelerometer 

array at its center of gravity. The pelvis 

is also instrumented with bi-lateral 

anterior-superior iliac spine (ASIS) load 

cells that measure contact force in a 

nominally longitudinal axis and 

moment about a nominally lateral axis. 

The ASIS load cell is primarily used to 

measure the force transferred to the 

pelvis through the lap belt, in which 

case the moments can be used to 

determine the vertical level or center of 

pressure of the lap belt force. 

K. Upper Leg 

The upper leg assembly is constructed 

of steel and aluminum and includes a 

rubber compressive element at the 

middle of the femur shaft. This 

compressive element consists of a steel 

plunger that can translate axially along 

the femur shaft through a guide system. 

When the femur is loaded in axial 

compression (e.g., pushing the knee 

towards the pelvis parallel to the 

femur), the motion of the plunger is 

resisted by a rubber element, which 

allows a human-like compression 

response.117 At the proximal end, the 

femur is connected to the pelvis through 

a ball joint in a socket attached to the 

acetabulum load cell. At the distal end, 

there is a six-axis load cell attaching the 

femur to the knee assembly. 

L. Knee 

The THOR–50M knee is similar in 

construction to that of the HIII–50M, 

with a few differences. The primary 

structure of the knee cap is fabricated 

from aluminum, attached proximally to 

the femur load cell. Inside of the 

kneecap assembly, a slider mechanism 

is installed to allow translational motion 

of the tibia with respect to the knee. The 

knee slider includes a stop assembly to 

prevent metal-to-metal contact and to 

define the force-deflection characteristic 

of the tibia translation. Attached to the 

slider is a string potentiometer to 

measure the magnitude of tibia 

translation relative to the knee. The 

sides of the kneecap are enclosed by 

urethane covers to protect the slider 

mechanism, and the knee assembly is 

wrapped in a foam-filled vinyl cover 

representing knee flesh. 

The design of the knee slider modifies 

the HIII–50M design by changing the 

geometry and material properties of the 

molded slider assemblies (472–5320 and 

472–5330) and stop assemblies (472– 

5358).118 This change was made because 

at levels of knee displacement below the 

10.2-millimeter (mm) biofidelity 

response requirement, the HIII–50M has 

been found to be stiffer than PMHS 

response corridors. Thus, during the 

THOR–50M Mod Kit project, 

biomechanical response requirements 

were specified with an additional 

measurement point at 5 mm of knee 

displacement with a force between 100 

and 500 N. The Mod Kit also relegated 

the measurement point at 10.2 mm of 

deflection to a secondary requirement, 

as it was shown to be at the high end 

of the underlying PMHS corridors. 

While the 5 mm and 17.8 mm response 

requirements were met by the revised 

THOR–50M knee slider,119 the forcedeflection response was below the 

human response corridor between 8 mm 

and 15 mm of deflection, but above the 

corridor after 18 mm of deflection.120 As 

such, when the biofidelity was 

evaluated using BioRank, the external 

biofidelity score of 2.282 indicated that 

the THOR–50M response was more than 

two standard deviations from the PMHS 

mean response. This BioRank score was 

lower than the corresponding HIII–50M 

score (1.070). This should be taken into 

consideration when using the THOR– 

50M to evaluate the risk of ligamentous 

knee injury. 

M. Lower Leg 

The mechanical design of the THOR– 

50M lower extremity includes a 

compressive rubber section in the tibia 

shaft, similar to the compliant femur 

section, which provides more biofidelic 

force transmission from the heel to the 

knee. The spring damper Achilles 

tendon system aids in producing 

biofidelic ankle motion and torque 

characteristics. The ankle design allows 

rotation about three axes, representing 

inversion/eversion, dorsi/plantarflexion, and axial rotation, and includes 

molded rubber elements to define the 

moment/rotation response and limit 

metal-to-metal contact at the extents of 

the range of motion. Different from 

existing ATDs, the THOR–50M includes 

a molded shoe design which integrates 

the foot and shoe into a single part. This 

feature, added in the 2016 update to the 

THOR–50M drawing package,121 is 

intended to reduce potential variability 

in the response of commercially 

available shoes. 

Euro NCAP TB026 deviates from the 

proposed drawing package in that it 

specifies the HIII–50M lower legs, 

including the military specification 122

shoes, knee slider sensor, and roller 

ball-bearing knees. We believe the 

THOR–50M specifications are 

preferable, for the reasons given above 

(e.g., biofidelity). 

Each lower leg can be instrumented 

with five-channel load cells in the 

upper and lower tibia, a uniaxial load 

cell to measure the Achilles cable force, 

and three rotary potentiometers to 

measure the rotation of the individual 

ankle joints. Two uniaxial 

accelerometers can be mounted to the 

tibia and a tri-pack accelerometer 

assembly can be mounted to each foot 

plate. 

N. Data Acquisition System 

Testing with THOR–50M requires (as 

does testing with any dummy) a data 


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123We note that the 2023 drawing package itself 

does not contain specifications for an in-dummy 

DAS. Instead, the proposed in-dummy DAS 

specifications are set out in an addendum that is 

being docketed along with the 2023 drawing 

package. 

124Alliance of Automobile Manufacturers, Inc. 

(2016). Technical Considerations Concerning 

NHTSA’s Proposal to Rework the Agency’s New Car 

Assessment Program (NCAP). Regulations.gov 

Docket ID NHTSA–2015–0119–0313, available at: 

https://www.regulations.gov/contentStreamer?

documentId=NHTSA-2015-0119-0313&

attachmentNumber=5&contentType=pdf. 

125TB026 § 1.2. 

126European New Car Assessment Programme 

(2022). Euro NCAP Supplier List, Version 4.0, 

October 2022, TB 029, available at: https://

www.euroncap.com/en/for-engineers/supportinginformation/technical-bulletins/. 

127European New Car Assessment Programme 

(2022). Euro NCAP Supplier List, Version 3.1, April 

2021, TB 029, available at: https://

www.euroncap.com/en/for-engineers/supportinginformation/technical-bulletins/. The DTS TDAS 

G5, SLICE Nano, and SLICE6; the Kistler DTI, 

microDAU, and NXT32; and the Messring M=BUS. 

128National Highway Traffic Safety 

Administration (2017). Implement and Install 

THOR 50M In Dummy Data Acquisition System. 

Solicitation Number DTNH2217Q00033, available 

at https://sam.gov/opp/068c7821de797ebe7f9

e78a0f2b68dc4/view. 

129Saunders, J., Parent, D. (2023). Update on 

NHTSA’s OMDB’s half barrier analysis. Proceedings 

of the 27th Enhanced Safety of Vehicle Conference, 

Yokohama, Japan. 

130The OVSC Laboratory Test Procedures for 

FMVSS No. 208 specify an ambient temperature 

measured within 36 inches of the ATD to be 

between 69 and 72 degrees Fahrenheit. National 

Highway Traffic Safety Administration (2008). 

Laboratory Test Procedure for FMVSS 208, 

Occupant Crash Protection, TP208–14, available at: 

https://www.nhtsa.gov/sites/nhtsa.gov/files/ 

documents/tp-208-14_tag.pdf. 

acquisition system (DAS). The data 

acquisition system performs signal 

conditioning, triggering, and data 

collection to store measurements from 

instrumentation installed in the dummy 

during a test into nonvolatile memory. 

As it relates to ATDs, there are 

effectively two types of DAS: external 

and internal (or in-dummy). As we 

explain below, while the 2018 drawing 

package does not specify a DAS 

(because it assumes the use of an 

external DAS), NHTSA is proposing to 

specify an optional in-dummy DAS.123

An external DAS is, as the name 

indicates, external to the dummy. The 

instrumentation in the dummy is 

connected to the external DAS via 

wires, sometimes referred to as an 

umbilical cable. The 2018 drawing 

package does not explicitly specify a 

DAS or related equipment, but the 

drawings assume an external DAS: they 

assume that the instrumentation wires 

are long enough to be bundled into an 

umbilical cable and connected to a DAS 

located in the lab or mounted to the 

vehicle in which the ATD is seated. 

An internal DAS is installed within 

the dummy itself. An internal DAS has 

some advantages to an external DAS. 

The primary advantage is related to the 

mass properties of the dummy. With an 

internal DAS system, there are no 

external cables that may possibly affect 

body segment masses; segment masses 

are always the same no matter how the 

dummy is used. While upfront cost is 

higher, an internal DAS would reduce 

per-test costs, eliminate the need for 

interface cables to lab-specific DAS 

systems (which have been a frequent 

sources of instrumentation failures in 

research testing), and reduce the 

adjustments needed to arrive at the 

target test vehicle weight. Feedback 

from industry 124 as well as Euro NCAP 

indicates that users prefer an in-dummy 

DAS for its many usability advantages. 

Euro NCAP TB026 requires an indummy DAS.125 While Euro NCAP 

TB029 currently does not specify an 

approved in-dummy DAS,126 earlier 

versions of TB029 did specify a few 

different approved in-dummy DAS 

systems.127

In light of these potential advantages 

and user preferences, NHTSA sponsored 

development and testing of an indummy DAS. NHTSA published a 

request for solicitation for an in-dummy 

DAS.128 This was before Euro NCAP 

began testing with the THOR–50M. The 

solicitation favored a minimal redesign 

of existing THOR–50M parts, in order to 

facilitate interchangeability of parts 

between THOR–50Ms with and without 

in-dummy DASs. NHTSA contracted 

Diversified Technical Systems (DTS) to 

implement its SLICE6 data acquisition 

system in a NHTSA-owned THOR–50M. 

This included delivery of DAS 

components, replacement 

instrumentation compatible with the 

DAS, and replacement ATD parts to 

allow attachment of DAS components 

and preservation of inertial properties. 

The resulting implementation 

distributes a series of small 6-channel 

data acquisition modules throughout the 

ATD, mounted directly on load cells or 

sensors where possible, or close to the 

sensor with short cables to the sensor. 

The DAS modules are chain-networked 

with four wiring harnesses which 

connect to the SLICE6 Distributor, with 

a single ATD exit cable connecting the 

DAS to the full test system. 

NHTSA evaluated the overall 

performance and equivalence of the 

THOR–50M with the in-dummy SLICE6 

DAS in a full suite of qualification 

testing and a variety of sled and vehicle 

crash testing. This research and analysis 

is described briefly below. The vehicle 

crash testing is described in more detail 

in the cited report. NHTSA is preparing 

a report on the installation, qualification 

testing, and sled testing of the SLICE6 

in-dummy DAS, which will be placed in 

the research docket when it is complete. 

Additional information on the 

durability of the THOR–50M with the 

in-dummy DAS system is included in 

Section VII.B, Durability and 

Maintenance. 

• It was possible to install the SLICE6 

into the dummy with negligible changes 

to the mass, moment of inertia, and 

center of gravity of the ATD and its 

individual body segments. This did 

require modifications to several THOR– 

50M parts (e.g., the lower thoracic spine 

assembly) in order to allow attachment 

of the DAS hardware to the rigid 

components of the ATD. 

• NHTSA has been able to fully 

qualify THOR–50M ATDs with the indummy DAS installed. Since the SLICE 

system has been installed, we have used 

the dummy in many tests and have 

qualified it with no issues. The THOR– 

50M with the in-dummy DAS was 

tested in simplified sled tests. Sled tests 

were conducted in the Gold Standard 1 

(40 km/h, 12g peak pulse, standard lap 

and shoulder belt) and Gold Standard 2 

(30km/h, 9g peak pulse, 3kN load 

limited shoulder belt) test conditions, 

which were used both in biofidelity 

assessment and in the development of 

thoracic injury criteria. The goal of this 

testing was to determine if any 

differences occurred between the 

external and internal DAS 

configurations, and if so, whether the 

magnitude of these differences would 

affect the biofidelity and injury criteria 

development analyses. 

• NHTSA also tested the THOR–50M 

with an in-dummy DAS in a series of 

vehicle crash tests in the OMDB test 

condition with three different 

deformable barrier faces. While some of 

the OMDB tests appeared to show 

differences between the in-dummy DAS 

and umbilical configurations, it was not 

clear whether this was due to variation 

in the dummy response or variation in 

dummy positioning, vehicle response, 

and/or restraint system response.129

Importantly, this testing did not 

reveal any potential durability or 

usability issues associated with the indummy DAS, with one possible 

exception: The temperature inside the 

thoracic cavity of the ATD can increase 

beyond the ambient temperature 

typically prescribed for regulatory and 

consumer information crash tests.130 In 

a more recent set of vehicle crash tests, 

NHTSA closely monitored the rib 

temperature of the THOR–50M with the 


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131Saunders, J., Parent, D., Martin, P. (2023). 

THOR–50M fitness assessment in FMVSS No. 208 

unbelted crash tests. Proceedings of the 27th 

Enhanced Safety of Vehicle Conference, Yokohama, 

Japan. 132Tatem, W., Louden, A. (2023). WorldSID–50M 

Fitness Assessment in FMVSS No. 214 Moving 

Deformable Barrier and Oblique Pole Crash Tests. 

Proceedings of the 27th Enhanced Safety of Vehicle 

Conference, Yokohama, Japan. 133This device is used to dissipate heat from the 

dummy in the pre-test setup (for example, while 

seating and positioning the dummy). Typically, a 

tube is inserted into the dummy jacket and in 

conjunction with the fan is used to vent heat from 

the dummy to maintain an in-spec internal 

temperature. The apparatus is detached from the 

dummy immediately prior to the vehicle or sled 

test. Use of such a fan may be specified in the OVSC 

laboratory test procedure. 

134While we are aware of in-dummy DASs 

produced by other manufacturers, we have not 

evaluated whether these systems would be 

compatible with the in-dummy DAS addendum to 

the 2023 drawing package. 

135Available at https://www.nhtsa.gov/researchdata/research-testing-databases#/biomechanics. 

136Overall, while some assumptions were 

necessary in the reproduction of the PMHS or 

volunteer test conditions, we believe that these 

assumptions should not affect the overall biofidelity 

assessment of the THOR–50M. For instance, 

NHTSA simplified some of the original tests in 

order to facilitate ease of testing when we expected 

the simplification to have a negligible influence on 

the result, such evaluating neck flexion using only 

the ATD’s head and neck, and not the entire 

dummy. These assumptions and simplifications, as 

well as any limitations to our analyses, are 

discussed in detail in the docketed biofidelity 

report. Parent, D., Craig, M., Moorhouse, K. 2017. 

Biofidelity Evaluation of the THOR and Hybrid III 

50th Percentile Male Frontal Impact 

Anthropomorphic Test Devices. Stapp Car Crash 

Journal, 61, 227–276, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0004. 

in-dummy DAS.131 By routinely 

limiting the ‘‘ON’’ time of the DAS, 

NHTSA has been able to maintain the 

temperature range. Additionally, 

NHTSA has used a portable fume 

extractor device to aid in maintaining 

the temperature of the WorldSID–50M 

side impact dummy, which also has 

internal DAS system.132 133 This device 

may also be employed in tests with the 

THOR–50M. 

Based on this testing, NHTSA has 

tentatively concluded that the THOR– 

50M with the in-dummy DAS is 

equivalent to one with the external 

DAS. NHTSA is therefore proposing an 

internal DAS as permitted optional 

instrumentation that it could use in its 

testing. This necessitates changes to the 

dummy to accommodate the DAS while 

ensuring that there are no changes to the 

mass, moment of inertia, and center of 

gravity of the ATD and its individual 

body segments. These changes may 

differ from the Euro NCAP approach 

specified in TB026, which permits the 

four-position spine box (discussed in 

Section III.H above) to accommodate the 

installation of some DAS brands by 

providing a mounting surface for data 

loggers. Euro NCAP does not provide 

part-by-part engineering drawings of the 

various DAS packages, which is 

necessary for THOR–50M to be 

sufficiently objective. 

NHTSA has therefore provided, in an 

addendum to the 2023 drawing package, 

further specifications for the dummy to 

accommodate an internal DAS. It is 

anticipated that, upon finalization of 

this proposal, the in-dummy DAS 

drawings will be fully integrated within 

the relevant technical data package 

components. These specifications 

consist of descriptions of the 

instrumentation and new drawings for 

the dummy parts that require 

modifications to accommodate the DAS. 

The changes are specified such that the 

dummy with the in-dummy DAS will 

have the same inertial properties as the 

dummy using the external DAS. The 

drawings show DAS mass blanks in lieu 

of the actual DAS components (battery, 

data logger, etc.) with the exterior 

dimensions of the blank matching those 

of the corresponding SLICE6 

component. 

If an in-dummy DAS component is 

not installed (for example, if lower leg 

instrumentation is not needed for a 

given test mode), the blank would be 

filled with a material of a specified 

density. The material of the blank is not 

specified (although a reference 

specification is provided) but would be 

selected to provide an appropriate 

density and may also have internal 

flashing holes needed to attain the 

desired mass, which is chosen to match 

the mass of the actual DAS component. 

It is anticipated that, upon finalization 

of this proposal, the PADI will show 

two sets of installation steps: one with 

the ‘‘blank’’ component, and one with 

the actual DAS parts. (This two-set 

convention is also followed with load 

cells and their structural replacements). 

The proposed specifications are based 

on, but not necessarily limited to, the 

SLICE6 (the SLICE6 is not explicitly 

specified or called-out by name), so that 

another system fitting within the 

defined specifications could also be 

utilized.134

NHTSA seeks comment from users 

who have experience with both 

umbilical and in-dummy DAS 

configurations of the THOR–50M, as to 

whether they have seen any quantifiable 

differences between the two. NHTSA 

also seeks comment on whether any 

additional changes should be made to 

the proposed drawings specifying the 

in-dummy DAS to make it more 

amenable to additional DAS systems 

that are already in the field. 

IV. Biofidelity 

Biofidelity is a measure of how well 

the dummy replicates a human, and 

includes anthropometry, mass 

properties, range of motion, and impact 

response. The impact biofidelity is 

evaluated by comparing the response of 

the dummy to the response of a postmortem human surrogate (PMHS or 

cadaver) or human volunteer in a 

variety of different test conditions (also 

referred to as test modes). Some of these 

tests focus on individual dummy 

components (head, neck, chest, 

abdomen, upper leg, knee, lower leg) 

and some evaluate the entire dummy as 

a complete assembly. 

To evaluate the biofidelity of THOR– 

50M, NHTSA selected test conditions 

based on relevance to frontal and frontal 

oblique crash test applications and the 

availability of data. For example, a neck 

frontal flexion test was conducted by 

attaching the base of the THOR–50M 

neck to a sled and applying a certain 

acceleration pulse. This was then 

compared to the response measured on 

human volunteers who were subjected 

to a similar pulse. Specifically, the 

impact biofidelity of the THOR–50M 

was assessed in twenty-one test 

conditions. The test conditions are 

summarized in Table 6. Each test 

produces a series of data points (e.g., 

force vs. time). 

The test conditions have been 

developed over the years by various 

researchers to evaluate biofidelity and 

have been published in peer-reviewed 

journals. The PMHS and human 

volunteer response data generally comes 

from this published research. The 

THOR–50M response data comes from 

testing that NHTSA has been 

conducting on the THOR–50M 

throughout its development, all of 

which is available in NHTSA’s 

Biomechanics Test Database.135 NHTSA 

also compared THOR–50M’s biofidelity 

to that of the HIII–50M; many of the 

tests conducted with THOR–50M were 

paired with the same test conducted on 

the HIII–50M. In our testing we 

attempted to match the test conditions 

as closely as possible to the test 

conditions in the original PMHS or 

volunteer tests.136


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137 63 FR 46981. 

138Mertz, H.J., Irwin, A.L., Melvin, J.W., Stanaker, 

R.L., & Beebe, M. (1989). Size, weight and 

biomechanical impact response requirements for 

adult size small female and large male dummies 

(No. 890756). SAE Technical Paper. 

139See National Highway Traffic Safety 

Administration, ‘‘Biomechanical Response 

Requirements of the THOR NHTSA Advanced 

Frontal Dummy, Revision 2005.1,’’ Report No: 

GESAC–05–03, U.S. Department of Transportation, 

Washington, DC, March 2005 (available at http:// 

www.nhtsa.gov/DOT/NHTSA/NVS/

Biomechanics%20&%20Trauma/THORNT%20Advanced%20Crash%20Test%20Dummy/

thorbio05_1.pdf) and Ridella, S., Parent, D., 

‘‘Modifications to Improve the Durability, Usability, 

and Biofidelity of the THOR–NT Dummy,’’ The 

22nd International Technical Conference for the 

Enhanced Safety of Vehicles, Paper No. 11–0312, 

2011. 

140Rhule, H., Maltese, M., Donnelly, B., Eppinger, 

R., Brunner, J., Bolte, J. (2002) Development of a 

New Biofidelity Ranking System for 

Anthropomorphic Test Devices. Stapp Car Crash 

Journal 46: 477–512. 

141Rhule, H., Moorhouse, K., Donnelly, B., 

Stricklin, J. (2009) Comparison of WorldSID and 

ES–2RE Biofidelity Using Updated Biofidelity 

Ranking System. 21st ESV Conference, Paper 

No.09–0563. 

142The analysis using Biorank described here 

mirrors (with some exceptions) the approach used 

in the assessment of the WorldSID 50th ATD. See, 

e.g., 80 FR 78522, 78538 (Dec. 16, 2015) (New Car 

Assessment Program Request for Comments); 71 FR 

75304 (Dec. 14, 2006) (final rule for ES–2re Side 

Impact Crash Test Dummy 50th Percentile Adult 

Male); 71 FR 7534 (Dec. 14, 2006) (final rule for 

SID–IIs Side Impact Crash Test Dummy 5th 

Percentile Adult Female). 

143The standard deviation is a statistic that 

measures the dispersion of a dataset relative to its 

mean. 

TABLE 6—BIOFIDELITY CONDITIONS CONSIDERED IN THE DESIGN OF THE HIII FRONTAL DUMMIES AND THOR–50M ATDS

Body region Test condition Subpart E, O, W THOR–50M 

Head .............................................. Isolated Head Drop .............................................................................. • • 

Whole-body Head Impact .................................................................... • 

Face Rigid Bar ..................................................................................... • 

Face Rigid Disk .................................................................................... • 

Neck .............................................. Neck Flexion, Pendulum ...................................................................... • 

Neck Extension, Pendulum .................................................................. • 

Neck Frontal Flexion, Sled .................................................................. • 

Neck Lateral Flexion, Sled ................................................................... • 

Neck Torsion ........................................................................................ • 

Thorax ........................................... Sternal Impact, 6.7 m/s ........................................................................ • 

Sternal Impact, 4.3 m/s ........................................................................ • 

Lower Ribcage Oblique ....................................................................... • 

Abdomen ....................................... Upper Abdomen Steering Rim ............................................................. • 

Lower Abdomen Rigid Bar ................................................................... • 

Abdomen Belt Loading ........................................................................ • 

KTH ............................................... Femur Compression ............................................................................ • • 

Knee Shear .......................................................................................... • • 

Lower Extremity ............................ Dynamic Heel Impact ........................................................................... • 

Tibia Axial Compression ...................................................................... • 

Dynamic Dorsiflexion ........................................................................... • 

Whole-body ................................... Gold Standard 1 ................................................................................... • 

Gold Standard 2 ................................................................................... • 

Gold Standard 3 ................................................................................... • 

Far Side Oblique .................................................................................. • 

The test conditions used to evaluate 

the THOR–50M represent an 

accumulation of biomechanics research. 

All conditions are accompanied by a 

well-specified, objective test procedure 

and a well-founded set of human 

response targets. The set of test 

conditions has grown substantially over 

the span of Part 572 rule makings. For 

example, in NHTSA’s original 1998 

proposal for the Subpart O HIII–5F 

dummy,137 only six biofidelity 

conditions were assessed.138 Since then, 

the list has grown substantially; new 

conditions have been developed for all 

body regions, and whole-body sled test 

conditions have been developed.139

NHTSA quantified how closely the 

response of the THOR–50M matched the 

response of the PMHS or human 

volunteers using the Biofidelity Ranking 

system (BioRank).140 BioRank has been 

applied in other instances cited in the 

literature 141 and in other NHTSA Part 

572 rulemakings.142 This methodology 

statistically compares the dummy 

response to the average PMHS/volunteer 

response (typically a time-series but 

sometimes a point estimate). A BioRank 

value of 0.0 indicates an ATD response 

identical to the average PMHS/volunteer 

response; a value of 1.0 indicates an 

ATD response that is on average one 

standard deviation 143 away from the 

average PMHS/volunteer response; a 

value of 2.0 indicates an ATD that is on 

average two standard deviations away 

from the average PMHS/volunteer 

response; and so on. Therefore, the 

lower the BioRank value, the better the 

biofidelity. We computed BioRank 

scores for both the THOR–50M and the 

HIII–50M. 

For each body region, we calculated 

two BioRank scores: one for external 

biofidelity (the extent to which the ATD 

represents a human surrogate to the 

vehicle or restraint system); and one for 

internal biofidelity (the ability of the 

ATD to represent the human responses 

that relate to prediction of injury). 

External biofidelity measures are 

generally those recorded at the test 

fixture level, such as pendulum force or 

belt force; internal biofidelity measures 

are generally those recorded by the 

internal instrumentation of the ATD or 

test equipment such as motion tracking 

that records subject excursion. 

NHTSA considered two other 

methods of quantifying biofidelity. One 

is the International Standards 

Organization (ISO) 9790 Biofidelity 

Classification System. ISO 9790 defines 

the analysis process, response corridors, 

and weighting factors for the 

quantitative assessment of biofidelity of 

side impact ATDs. Because the ISO 

9790 response corridors and weighting 

factors are specific to side-impact ATDs, 

it could not be directly applied to a 

frontal impact ATD such as the THOR– 

50M, and we are not aware of a 

corollary ISO standard for assessment of 

frontal impact ATD biofidelity. While a 

method similar to that described in ISO 

9790 could be developed to assess 

frontal impact ATD biofidelity, we 

believe such a method may introduce 

subjective bias because it contains many 

subjective features, including weighting 


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144Rhule, D., Rhule, H., Donnelly, B. (2005) The 

Process of Evaluation and Documentation of Crash 

Test Dummies for Part 572 of the Code of Federal 

Regulations. 19th ESV Conference, Paper No. 05– 

0284, pp. 9–10. 

145 Gehre C, Gades H, Wernicke P (2009) 

Objective rating of signals using test and simulation 

responses, The 21st International Technical 

Conference for the Enhanced Safety of Vehicles, 

Paper No. 09–0407, 2009. 

146Parent, D., Craig, M., Moorhouse, K. 2017. 

Biofidelity Evaluation of the THOR and Hybrid III 

50th Percentile Male Frontal Impact 

Anthropomorphic Test Devices. Stapp Car Crash 

Journal, 61, 227–276, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0004. 

147The qualitative biofidelity of the shoulder is 

also discussed in the Biofidelity Report, where the 

role of the shoulder in belt retention (or lack 

thereof) is discussed qualitatively. See p. 272–273. 

148This finding has been confirmed by 

independent research; a 2018 study showed that the 

HIII–50M and THOR–50M demonstrated similar 

biofidelity scores in a sled test environment 

representing a production vehicle. See Albert, 

Devon L., Stephanie M. Beeman, and Andrew R. 

Kemper. ‘‘Occupant kinematics of the Hybrid III, 

THOR–M, and postmortem human surrogates under 

various restraint conditions in full-scale frontal sled 

tests.’’ Traffic Injury Prevention 19.sup1 (2018): 

S50–S58. 

of test conditions and body regions.144

The BioRank system was developed to 

minimize subjectivity in the areas of 

corridor development, weighting, and 

scoring. Another method NHTSA 

considered is correlation and analysis 

(CORA), which may be a useful tool to 

carry out quantitative analysis.145

However, the vast array of tunable 

parameters in the software can result in 

unintentional subjectivity and poor 

reproducibility. Further, there are no 

known and accepted relationships 

between CORA scores and biofidelity 

classifications. Accordingly, we 

evaluated biofidelity using BioRank. 

We note that because many of the 

biofidelity test conditions utilize 

specialized instrumentation or test 

equipment, they are not intended to be 

carried out as certification or 

qualification tests conducted between 

crash tests or sets of crash tests to 

confirm that specified ATD response 

requirements are met. Instead, due to its 

relative complexity, biofidelity testing is 

carried out at the ATD design stage to 

assess the biofidelity of the design. 

Simplified and standardized versions of 

the biofidelity test conditions have been 

developed as qualification procedures 

for some body regions. Because the 

qualification response requirements are 

based on the expected variation in 

response of the ATD, not the underlying 

human response, the qualification 

requirements specify a much smaller 

allowable range in response than the 

biomechanical design targets. Therefore, 

it is expected that all THOR–50M units 

that meet the specifications of the 

qualification procedures would 

demonstrate similar biofidelity. The 

proposed qualification response 

requirements are discussed in Section 

V. 

A full description of NHTSA’s 

biofidelity testing and analysis can be 

found in the docketed biofidelity 

report.146 We note that there are no 

separate discussions in the report for the 

shoulder, spine, or pelvis. Impact 

biofidelity of the spine and pelvis, as 

well as the dynamic biofidelity of the 

shoulder, are intrinsically evaluated as 

part of the whole-body biofidelity sled 

test series.147 Shoulder biofidelity has 

also been assessed quasi-statically and 

found to be more similar to the human 

volunteer corridors than existing ATDs. 

NHTSA is finalizing a report on the 

alternate shoulder design, which 

includes the biofidelity evaluation 

described here; once complete, this 

report will be published to the research 

docket. 

NHTSA believes that the THOR–50M 

is sufficiently biofidelic for 

incorporation into Part 572. The 

biofidelity report shows that the THOR– 

50M exhibits overall internal and 

external BioRank scores of below 2.0. 

See Table 7. Both internal and external 

BioRank scores are lower than those of 

the HIII–50M, which is defined in Part 

572 (Subpart E) and used in regulatory 

and consumer information frontal 

impact crash testing. At the body region 

level, the internal and external BioRank 

scores for THOR–50M are all below 2.0 

except for neck internal biofidelity and 

abdomen external biofidelity. The 

THOR–50M BioRank score for the neck 

and abdomen external biofidelity are, 

however, lower (better) than those for 

the HIII–50M. Overall, the internal 

BioRank scores for the THOR–50M were 

lower than those of HIII–50M in 5 of the 

7 body regions evaluated, and THOR– 

50M external BioRank scores were 

lower than those of HIII–50M in 6 of the 

7 body regions evaluated. Thus, the 

THOR–50M has generally improved 

biofidelity in the individual body region 

tests, which improves the accuracy of 

injury predictions. The THOR–50M and 

the HIII–50M have comparable 

quantitative biofidelity in the wholebody sled test conditions.148

TABLE 7—BODY REGION INTERNAL AND EXTERNAL BIORANK SUMMARY

Body region 

THOR–50M HIII–50M 

Internal External Internal External 

Head ................................................................................................................ 0.155 1.143 0.013 6.640 

Neck ................................................................................................................. 2.155 1.677 2.185 4.318 

Thorax .............................................................................................................. 0.917 0.948 1.603 2.070 

Abdomen .......................................................................................................... 1.470 2.803 1.629 3.474 

KTH .................................................................................................................. 1.400 1.731 3.875 6.667 

Lower Extremity ............................................................................................... 1.349 0.871 0.832 1.108 

Whole-body ...................................................................................................... 1.472 1.989 1.576 1.780 

Overall ...................................................................................................... 1.274 1.594 1.673 3.722 

Since a majority of the test conditions 

involved pure frontal loading, and 

several involved oblique and lateral 

loading (neck lateral flexion, neck 

torsion, lower thorax oblique, Gold 

Standard 3, and Far Side Oblique test 

conditions), these findings are expected 

to extend to frontal and frontal oblique 

crash test conditions. The findings may 

not, however, extend to other loading 

conditions (such as pure lateral or rear 

impacts) without further research. 

V. Qualification Tests 

This NPRM proposes qualification 

tests (also referred to as qualification 

procedures) for THOR–50M. The 

qualification procedures describe a 

series of impact tests performed on a 

fully-assembled dummy or dummy subassembly. The tests assess the 

components that play a key role in the 

dummy’s performance in the intended 

application of frontal and frontal 

oblique crashes. We propose 


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149At the same time, conformance to a 

qualification requirement is not a substitute for 

parts that do not conform to drawing specifications. 150HIII–10C, Subpart T. 

qualification tests for the head, face, 

neck, upper thorax, lower thorax, 

abdomen, upper leg, knee, and lower 

leg. For some body regions (such as the 

face) we propose a single test condition 

(also referred to as a test mode), while 

for other body regions (for example, the 

neck) we propose a series of different 

test conditions. 

Each qualification test condition 

consists of test procedures, test 

parameters, and acceptance intervals. 

The test procedures describe a detailed 

series of steps that must be carried out 

to perform the test. Test parameters 

describe specific aspects of the 

dummy’s response. Acceptance 

intervals (or qualification targets) are 

specified for each test parameter. 

Acceptance intervals are a typically pair 

of numeric values (a minimum value 

and maximum value) within which the 

dummy response must fall in order to 

pass, but can also represent a minimum 

or maximum value of the response. For 

instance, one of the tests involves 

striking the head with an impactor and 

measuring the head’s acceleration, 

which must be within the acceptance 

interval 117 ± 11.7 Gs. 

The qualification tests mirror the 

dummy loading patterns observed in 

frontal crash tests, including full frontal, 

oblique, and offset modes. For the neck 

assembly, we have specified separate 

requirements in flexion, extension, and 

lateral flexion. These bending modes 

have all been observed in crash testing. 

Additionally, a torsion test is prescribed 

for the neck since it also twists along its 

long axis to some degree. For the feet 

and ankles, tests in inversion, eversion, 

dorsiflexion, and axial loading through 

the tibia are specified to account for the 

various injurious loads that have been 

observed in crash tests. For the head, 

face, upper and lower thorax, abdomen, 

upper legs, and knees, we have only 

prescribed impact tests to anterior 

aspects since injurious loads pass 

primarily through those aspects during 

crash testing. The impact speeds and 

probe masses have been selected to 

demonstrate that the various body 

segments work properly at energy levels 

at or near those associated with high 

injury risks. For measurements not 

associated with an injury criterion, 

energy levels are chosen to exercise the 

dummy approaching its functionality 

limits, but without causing damage. 

The qualification tests ensure that the 

dummy is functioning properly. There 

are a few inter-related aspects to this. 

One is that qualification tests ensure 

that dummy components and sensors 

are properly assembled and functioning. 

Qualification tests monitor the response 

of components that may have become 

loosened or misaligned since initial 

assembly. For each test, certain dummy 

sensors and signal characteristics (such 

as the magnitude and timing) have been 

specified as qualification targets. Loose 

or misaligned parts may become evident 

when a signal does not conform to the 

prescribed signal characteristics. By 

monitoring these sensors, the 

qualification tests ensure that the 

dummy is functioning properly. The 

tests also ensure that the sensors 

themselves are working properly. 

Another aspect is that qualification tests 

help identify components that have 

deteriorated over time, preventing the 

dummy from meeting the qualification 

targets; such parts need to be replaced 

or refurbished. Many of the qualification 

test protocols are very similar to the 

dynamic tests used to assess biofidelity. 

This helps to ensure that a qualified 

dummy is also a biofidelic dummy. 

Finally, they ensure that the dummy or 

particular sub-assembly is responding in 

a uniform and expected manner; if it is 

not, certain dummy components might 

need to be tuned or adjusted to obtain 

a response within the qualification 

targets. 

NHTSA’s experience has shown that 

the impact tests on body segments are 

needed to ensure uniformity of dummy 

responses in a subsequent vehicle crash 

test. In other words, full conformance to 

part and assembly specifications (in 

accordance with the drawings and 

PADI) is not enough to guarantee a 

uniform dummy response in a crash 

test.149 Qualification tests have proven 

reliable and sound in qualifying 

NHTSA’s other test dummies. Moreover, 

some of the proposed qualification tests 

use the same test equipment as other 

ATDs, thus minimizing the amount of 

new qualification equipment needed by 

test laboratories that may already have 

such equipment in place for qualifying 

other ATDs. Meeting the qualification 

tests helps ensure that the dummy is 

capable of responding properly in a 

compliance or research test. This in turn 

helps to ensure that the dummy is an 

objective test device suitable for the 

assessment of occupant safety in 

compliance tests specified in Federal 

Motor Vehicle Safety Standards, and for 

other testing purposes. 

NHTSA proposes setting the 

qualification targets at ± 10% of the 

mean response for each qualification 

parameter as reported in the 

qualification test R&R study (discussed 

in Section VI). In that study we 

subjected multiple dummies to repeated 

tests in each test condition at multiple 

test laboratories. The repeatability 

testing and analysis for the qualification 

tests is described in more detail in 

Section VI.A. We believe that 10% is 

wide enough to account for normal 

variations in ATD and laboratory 

differences, and narrow enough to 

ensure consistent and repeatable 

measurements in standardized testing 

with the ATD. This is also consistent 

with the qualification limits for the 

other Part 572 ATDs. For example, for 

the Hybrid III 10-year-old child dummy, 

the acceptance intervals are, on average, 

set at ±9.9% from the nominal 

midpoint, with a low of 8.4% (neck 

rotation in the neck extension test) and 

a high of 10.8% (in the neck moment in 

the extension test and chest deflection 

in the thorax impact test).150 For all Part 

572 ATDs, the average acceptance 

interval is ±11%. 

We also considered setting the 

qualification targets at plus or minus 

two standard deviations from the mean 

response observed in the testing 

reported in the repeatability and 

reproducibility study. This would have 

narrowed the acceptance interval for 

almost all responses, some of which 

would have been unreasonably narrow. 

For instance, the head impact test 

results in the repeatability and 

reproducibility study were very 

uniform, with a CV for peak force of 

0.9%. If the acceptance interval for peak 

force were set to plus or minus two 

standard deviations (±1.8%), 24 of the 

26 trials would have resulted in a pass; 

if it were set to ±2.5%, all 26 trials 

would have resulted in a pass. This 

result may have been a function of using 

only three THOR–50M units in the test 

series, all of which were brand new 

when we tested them. Therefore, we 

propose a greater allowance of ±10% for 

all qualification requirements to account 

for slight variations that may arise from 

equipment and testing variations at 

different test labs as well as a future 

population of THOR–50M units from 

dummy manufacturers in which lot-tolot differences in the fabrication of parts 

from the same manufacturer may exist. 

It also allows for slight changes to 

individual THOR–50M units over time, 

either due to aging of polymeric 

components or wear and tear under 

normal use. Table 8 summarizes the 

proposed THOR–50M qualification 

requirements. 


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151 § 2.1. 

TABLE 8—PROPOSED THOR–50M QUALIFICATION REQUIREMENTS

Test Measurement Units Nominal target Acceptance 

interval 

1. Head Impact ..................... Peak Probe Force ............................................................... N ................... 5580 5022–6138 

Peak Head CG Resultant Acceleration .............................. G ................... 117.0 105.3–128.7 

2. Face Impact ...................... Peak Probe Force ............................................................... N ................... 7098 6378–7796 

Peak Head CG Resultant Acceleration .............................. G ................... 138 124–152 

3. Neck Flexion ..................... Peak Upper Neck My ......................................................... N-m ............... 31.0 27.9–34.1 

Upper Neck Fz Most Positive Value Prior to 40 ms .......... N ................... 860 774–946 

Peak Head Angular Velocity ωy (relative to earth) ............. deg/sec ......... 1975 1777–2172 

Peak Head Rotation (relative to pendulum) ....................... deg ................ 64.5 58.1–71.0 

4. Neck Extension ................. Peak Upper Neck My .........................................................

Peak Upper Neck Fz ..........................................................

N-m ...............

N ...................

23.0 

2918 

20.7–25.3 

2626–3210 

Peak Head Angular Velocity ωy (relative to earth) ............. deg/sec ......... 2061 1855–2267 

Peak Head Rotation (relative to pendulum) ....................... deg ................ 65.0 58.5–71.5 

5. Neck Lateral ...................... Upper Neck Mx first peak after 40.0 ms ............................ N-m ............... 49.7 44.8–54.7 

First Peak Head Angular Velocity ωx (relative to earth) ..... deg/sec ......... 1362 1226–1498 

Peak Head Rotation (relative to pendulum) ....................... deg ................ 41.7 37.6–45.9 

6. Neck Torsion ..................... Peak Upper Neck Mz ......................................................... N-m ............... 41.4 37.3–45.6 

First Peak Upper Neck Angular Velocity ωz (relative to 

earth).

deg/sec ......... 1390 1251–1529 

Peak Neck Fixture Rotation ................................................ deg ................ 47.9 43.1–52.7 

7. Upper Thorax .................... Peak Probe Force ...............................................................

Peak Upper Resultant Deflection .......................................

N ...................

mm ................

3039 

53.6 

0–3039 

48.3–59.0 

Difference Between Peak Left & Right Resultant Deflections.mm ................ 0 ¥5 to 5 

Force at Peak Resultant Deflection .................................... N ................... 2677 2409–2944 

8. Lower Thorax .................... Peak Probe Force ...............................................................

Resultant Deflection at Peak Force ....................................

N ...................

mm ................

3484 

50.9 

3136–3832 

45.8–56.0 

9. Lower Abdomen ................ Peak Probe Force ...............................................................

Lower Abdomen X-axis Deflection at Time of Peak Force 

N ...................

N ...................

2918 

83.0 

2626–3210 

74.7–91.3 

Difference Between Peak Left & Right X-axis Deflections mm ................ 0 ¥8 to 8 

10. Upper Leg ....................... Peak Probe Force ............................................................... N ................... 8333 7500–9166 

Peak Femur Force, Fz ........................................................ N ................... 4920 4428–5412 

Peak Resultant Acetabulum Force ..................................... N ................... 2738 2464–3012 

11. Knee ................................ Peak Femur Z-axis Force ................................................... N ................... 6506 5855–7156 

Knee Deflection at Peak Femur Force ............................... mm ................ 20.2 18.2–22.2 

12. Ankle Inversion ............... Peak Lower Tibia Fz ...........................................................

Peak Ankle Resistive Moment ............................................

N ...................

N-m ...............

505 

39.1 

454–555 

35.2–43.0 

Peak Ankle X-axis Rotation ................................................ deg ................ 34.5 31.0–37.9 

13. Ankle Eversion ................ Peak Lower Tibia Fz ...........................................................

Peak Ankle Resistive Moment ............................................

N ...................

N-m ...............

571 

43.0 

514–629 

38.7–47.3 

Peak Ankle X-axis Rotation ................................................ deg ................ 29.6 26.6–32.5 

14. Ball of Foot ..................... Peak Lower Tibia Fz ........................................................... N ................... 3170 2853–3487 

Peak Ankle Resistive Moment ............................................ N-m ............... 55.3 49.8–60.8 

Peak Ankle Y-axis Rotation (in dorsiflexion) ...................... deg ................ 33.8 30.4–37.2 

15. Heel ................................. Peak Lower Tibia Fz ........................................................... N ................... 3162 2846–3478 

Note: For comparison purposes, unless otherwise noted, only positive values are shown for the Nominal Target and Acceptance Range. Some 

targets, such as Neck Flexion Angular Velocity (wy = –1362 deg/sec), are defined by negative values. 

The proposed qualification 

requirements are the same as the 2018 

version except for the upper leg; this is 

discussed in the section below for the 

upper leg. 

Euro NCAP TB026 explicitly adopts 

NHTSA’s 2018 qualification 

procedures 151 with a couple of 

differences. First, there are a few 

differences between the proposal and 

TB026 with respect to the tests or test 

parameters. TB026 specifies somewhat 

different qualification metrics for the 

upper thorax test and does not include 

a face impact test. TB026 prescribes the 

upper leg test described in NHTSA’s 

2018 qualification procedures, which 

we are proposing to update. And, 

because TB026 specifies the HIII–50M 

lower extremities, the corresponding 

qualification tests are not the same as 

those proposed. Second, although 

TB026 adopts the rest of the 2018 

qualification test procedures and test 

parameters, it specifies acceptance 

intervals that differ from the proposed 

acceptance intervals with respect to 

both the width and midpoint of the 

interval. While the proposed acceptance 

intervals are ±10% around the mean (as 

calculated from our R&R testing), the 

width of the acceptance intervals 

specified in TB026 range from 1% to 

10%, with many of them less than 10%. 

In addition, the midpoint of these 

intervals differs from the means NHTSA 

calculated based on its R&R testing. For 

nine of the parameters, the TB026 

specifications are fully contained within 

the proposed acceptance intervals. Of 

the remaining parameters, there is a 

minimum of 82% overlap between the 

Euro NCAP specifications and the 

proposed acceptance intervals. 

Therefore, it is feasible, but not 

guaranteed, for a THOR–50M which 

meets the Euro NCAP acceptance 

intervals to also meet the proposed 

acceptance intervals. NHTSA has 

tentatively decided not to adopt 

narrower acceptance intervals, such as 

those specified in TB026, for the reasons 

given above. Moreover, NHTSA is 

unaware of the data on which the Euro 

NCAP specifications are based, whereas 

the proposed specifications are based on 

NHTSA’s carefully-controlled study. 

The differences between the proposed 


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61920 Federal Register / Vol. 88, No. 172 / Thursday, September 7, 2023 / Proposed Rules 

152Craig, M., Parent, D., Lee, E., Rudd, R., 

Takhounts, E., Hasija, V. (2020). Injury Criteria for 

the THOR 50th Male ATD. Regulations.gov Docket 

ID NHTSA–2019–0106–0008, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0008. 

153The range was 104–1262 and the standard 

deviation was 210. 

154Craig et al (2020), Injury Criteria for the THOR 

50th Male ATD. 155 49 CFR 572.33 Neck. 156 49 CFR 572.34 Thorax. 157Craig et al (2020), Injury Criteria for the THOR 

50th Male ATD. 

qualification tests and those specified in 

TB026 are discussed in more detail in 

the relevant sub-sections below. In 

addition, the proposed qualification test 

parameters and acceptance intervals and 

the corresponding TB026 values are 

summarized in Appendix G. 

We propose to set out the 

qualification procedures in a separate 

document that would be incorporated 

by reference into Part 572. See Section 

XI, Incorporation by reference. This 

would be a departure from the other 

ATDs currently specified in Part 572, for 

which the qualification tests are set out 

in full in the regulatory text in each of 

the relevant paragraphs (corresponding 

to that ATD) in part 572. We are 

proposing a separate qualification 

procedures document for THOR–50M 

because the THOR–50M qualification 

procedures contain many photographs 

and diagrams that are not amenable to 

publication in the CFR; we believe this 

extra level of detail will be helpful for 

end users who are attempting to qualify 

the ATD. 

NHTSA seeks comment on the 

proposed qualification tests. NHTSA 

also seeks any qualification data 

commenters are able to provide, as long 

as the data are from THOR–50M ATDs 

conforming to the 2023 drawing package 

and were collected following the April 

2023 Qualification Procedures Based on 

any comments and data received, 

NHTSA might consider changing the 

qualification targets to reflect the larger 

population of THOR–50M units in the 

field. However, before doing so we 

would assess the effect that any change 

could have on the biofidelity of the 

dummy and the applicability of injury 

risk functions. We also seek comment 

on whether we should incorporate the 

qualification procedures by reference, or 

whether it would be preferable to locate 

a much-simplified set of qualification 

procedures directly in Part 572 and put 

additional detail and documentation in 

the Office of Vehicle Safety Compliance 

(OVSC) laboratory test manual or 

similar document that would not be 

incorporated by reference but instead 

provided as guidance to DOT 

contractors and other ATD end users. 

A. Head Impact 

The head qualification test is identical 

to the whole-body head impact 

biofidelity assessment, where a fullyassembled THOR–50M is seated on a 

table and impacted on the forehead with 

a 23.36 kg rigid impactor at 2.00 ± 0.05 

m/s. This test serves as a surrogate for 

the isolated head drop test used by other 

ATDs; due to the construction of the 

head and neck of the THOR–50M ATD 

(specifically, the integration of the neck 

spring cables into the skull), separation 

of the head from the neck is not feasible. 

The test assesses the performance of the 

head skin and CG accelerometers, which 

are used to calculate HIC15.152 The 

probe force and the head CG resultant 

acceleration are measured and would 

have to be within the proposed 

acceptance intervals. 

B. Face Impact 

The face qualification test is identical 

to the face rigid disk impact biofidelity 

assessment, where a fully-assembled 

THOR–50M is seated on a table and 

impacted on the face with a 13 kg rigid 

impactor with a 152.4 mm diameter flat 

disk impact surface at 6.73 ± 0.05 m/s. 

This test assesses the impact response of 

the face, which is driven primarily by 

the face foam insert (Part No. 472–1401). 

Additionally, as this test is more severe 

than the head impact test, it assesses the 

head CG accelerometers (which are used 

to calculate HIC15) at a level of severity 

closer to that expected from vehicle 

crash tests. FMVSS No. 208 specifies a 

maximum calculated HIC15 value of 700 

for the HIII–50M, and the average HIC15

measurement from a set of 29 vehicle 

crash tests in either the full frontal rigid 

barrier or OMDB crash test modes was 

285.153 The head impact test, however, 

results in an average HIC15 of 157 

(probability of AIS 3+ injury of 0.05%), 

while the face impact is more severe, 

with an average HIC15 of around 450 

(probability of AIS 3+ injury of 3.5%). 

Therefore, compared to the head impact 

test, the face impact test is a better 

assessment of the head response at a 

severity level expected from vehicle 

crash tests, as it results in a HIC15 that 

is closer to the current FMVSS No. 208 

injury assessment reference value. 

During these tests, the probe force and 

the head center of gravity (CG) resultant 

acceleration are measured and would 

have to be within the proposed response 

corridors. 

C. Neck 

The proposed neck qualification test 

series, in which the entire head-neck 

assembly is removed from the ATD and 

affixed to the conventional Part 572 

swinging pendulum to apply a 

prescribed impulse to the neck, includes 

six tests: flexion, extension, left lateral 

flexion, right lateral flexion, left torsion, 

and right torsion. The swinging 

pendulum apparatus serves as a 

surrogate for the more complex neck 

biofidelity assessment, which is carried 

out in a sled test configuration. The 

neck qualification tests assess the 

collective performance of the molded 

neck column, the occipital condyle cam 

and associated bump stops, and the 

neck spring towers. In the process, the 

neck qualification tests assess the 

performance of the upper neck load cell, 

from which the Z-axis force and Y-axis 

moment are used to calculate Nij.154

The neck axial force, neck moment 

about the relevant axis, and neck 

rotation about the relevant axis are 

measured and would have to be within 

the proposed acceptance intervals. The 

neck flexion and extension qualification 

tests are similar to those specified for 

the HIII–50M 155 in that they use the 

same pendulum and similar 

deceleration specifications. 

D. Upper Thorax 

This test involves impacting the chest 

of a fully-assembled THOR–50M seated 

on a table with a rigid impactor. The 

upper thorax qualification test is 

configured similarly to that carried out 

on the HIII–50M,156 using the same 

pendulum (23.36 kg, 152.40 mm 

diameter) to impact the mid-sternum, 

but at a lower impact velocity of 4.3 

meters per second. This test assesses the 

dynamic thoracic response to sternal 

impact as well as the functionality of 

the upper left and upper right thoracic 

deflection instrumentation. This test 

condition is identical to the associated 

biofidelity assessment, though the 

qualification test uses only internal 

deflection measurements so that motion 

tracking or other external 

instrumentation is not required. Several 

measurements must be within the 

proposed acceptance intervals: the peak 

overall probe force, the peak upper left 

and upper right resultant deflections, 

the difference between the peak left and 

right resultant deflections, and the 

probe force at the peak left and right 

resultant deflections. 

In the 2016 qualification procedures, 

the upper thorax qualification required 

individual X-axis and Z-axis deflection 

specifications for both the upper left 

and upper right thorax. This was revised 

in the 2018 qualification procedures by 

specifying the peak resultant deflection 

instead, which better aligns with the 

peak resultant deflection measure used 

to evaluate thoracic injury risk.157


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158 In addition, some members of Working Group 

5 have observed variations in the ATD responses in 

the upper thorax qualification tests that have led to 

difficulties in meeting the Euro NCAP qualification 

specifications, and have suggested that this may 

result from variation in the spine flex joint, 

potentially due to material that was not as hard as 

the specification called for. 

Applying specifications on the resultant 

deflection instead of two individual 

components allows for a reduction in 

the overall number of required 

measurements, while still capturing the 

physical response of the dummy since 

the X-axis and Z-axis deflections are the 

primary components of the resultant 

deflection in this test condition. 

The Euro NCAP qualification 

response requirements differ from the 

proposal in three ways. First, they 

include an additional parameter: the 

ratio of Z-axis to X-axis deflection. 

Second, they do not require a maximum 

difference between left and right peak 

resultant deflection, whereas the 

proposed qualification targets limit the 

left-to-right difference to 5 millimeters. 

Using the Euro NCAP targets, the 

difference between the left and right 

peak resultant deflections could be as 

high as 7.2 millimeters. Third, as noted 

above, the qualification targets are 

narrower than the proposed 

qualification targets. 

NHTSA has tentatively decided not to 

specify the ratio of Z-axis to X-axis 

deflection because doing so would 

effectively revert to the 2016 approach 

of individual X-axis and Z-axis 

deflection requirements, which would 

increase the difficulty in meeting the 

qualification specification without a 

direct link to injury prediction, as the 

peak resultant deflection specification is 

of primary importance because it is the 

metric used in the calculation of 

thoracic injury risk. 

NHTSA is aware that the upper thorax 

qualification specification has been a 

topic of frequent discussion within the 

International Standards Organization 

(ISO) working groups (particularly ISO/ 

TC 22/SC 36, Safety and impact testing, 

Working Groups 5, Anthropomorphic 

Test Devices, and 6, Performance 

criteria expressed in biomechanical 

terms). NHTSA understands that those 

discussions have focused on potential 

modifications to the drawing package to 

meet the upper thorax qualification 

response requirements (in the context of 

testing related to Euro NCAP). Those 

modifications—specifically, the shorter 

rib guide, the individual rib 

performance test, and changes in the 

area of the coracoid process—have been 

discussed as describe in Section III, 

Design, Construction, and 

Instrumentation.158 NHTSA does not 

believe the modifications are necessary 

to meet the proposed upper thorax 

qualification requirements because 

NHTSA’s repeatability and 

reproducibility testing showed that 

those requirements were achieved by 

three different THOR–50M units at three 

different test labs. See Section VI, 

Repeatability and Reproducibility. 

Moreover, it is not clear whether these 

changes would preclude a THOR–50M 

from meeting the proposed qualification 

requirements, though since the Euro 

NCAP specifications are narrower, any 

variation caused by these changes may 

be within the NHTSA’s proposed 

acceptance intervals. Before 

implementing any of these design 

changes, the performance of the 

prototype parts would need to be 

evaluated. 

In an effort to further investigate these 

contemplated changes to THOR–50M, 

NHTSA analyzed its upper thorax 

qualification test data. NHTSA’s limited 

analysis suggests that the difficulty 

meeting the Euro NCAP upper thorax 

qualification requirements might stem 

not from the dummy design, but from 

the smaller allowable range of peak 

resultant deflection and the addition of 

the deflection ratio corridor specified in 

TB026. However, it would be necessary 

to know how the Euro NCAP upper 

thorax qualification requirements were 

determined to carry out a complete 

analysis. This preliminary analysis is 

discussed in more detail in Appendix A. 

E. Lower Thorax 

The lower thorax qualification test is 

unique to the THOR–50M. This test 

involves impacting the lower thorax of 

a fully-assembled THOR–50M seated on 

a table with a rigid impactor. It is 

similar to the upper thorax qualification 

test, as it uses the same pendulum 

(23.36 kg, 152.40 mm diameter) at the 

same impact velocity (4.3 meters per 

second). The test assesses the dynamic 

impact response of the lower torso, to 

which the rib cage and the upper and 

lower abdomen assemblies contribute, 

while at the same time assessing the 

functionality of the lower left and upper 

right thoracic deflection 

instrumentation. The lower thorax 

qualification test is a simplification of 

the lower ribcage oblique impact 

biofidelity condition. In the biofidelity 

condition, the torso is rotated by 15 

degrees and a chestband is used to 

measure external deflection. In the 

qualification condition, the torso is not 

rotated, but instead offset relative to the 

line of travel of the pendulum such that 

the pendulum is centered on the lower 

left or lower right anterior attachment 

point of the thoracic deflection 

instrumentation. As in the upper thorax 

condition, the lower thorax qualification 

mode uses internal deflection 

measurements so that motion tracking 

or other external instrumentation is not 

required. During this test, the peak 

overall probe force and the peak 

resultant thoracic deflection at the time 

of peak probe force are measured and 

would have to be within the proposed 

acceptance intervals. 

F. Abdomen 

This test (which is unique to the 

THOR–50M) impacts the lower 

abdomen of a fully-assembled THOR– 

50M with a 177.8 mm by 50.8 mm rigid 

rectangular face impactor, weighing 

32.00 kg, at 3.30 m/s. It was originally 

based on the lower abdomen rigid bar 

biofidelity condition, though several 

modifications were made over time to 

increase its objectivity and improve its 

utility as a qualification test. This test 

assesses the dynamic response of the 

lower abdomen, including the jacket, 

lower abdomen foam inserts, and lower 

abdomen bag, as well as the 

functionality of the abdominal 

deflection instrumentation. The peak 

overall probe force, the peak left and 

right X-axis abdomen deflection at the 

time of peak probe force, and the 

difference between the left and right Xaxis deflection at the time of peak probe 

force are measured and would have to 

be within the proposed acceptance 

intervals. 

G. Upper Leg 

The upper leg qualification test 

assesses the dynamic impact 

performance of the knee flesh, knee 

flesh insert, and femur compression 

element, while evaluating the 

functionality of the femur and 

acetabulum load cells. The full THOR– 

50M is seated on a table with a posterior 

restraint adjacent to the pelvis flesh and 

impacted at the knee by a 12.00 kg 

impactor with a 76.2 mm diameter rigid 

disk impact surface at 3.3 ± 0.05 m/s 

parallel to the femur. The peak probe 

force, peak femur Z-axis force, and peak 

resultant acetabulum force would have 

to be within the proposed acceptance 

intervals. 

This differs from the test procedure in 

the 2018 Qualification Procedures 

Manual in the THOR–50M research 

docket. The 2018 draft qualification test 

procedures for impacting the knee 

specifies the use of a 5.0 kg impactor at 

2.6 m/s. NHTSA’s repeatability and 

reproducibility testing of the 

qualification procedures, however— 

which used the 2018 draft procedures— 

resulted in coefficients of variation 


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61922 Federal Register / Vol. 88, No. 172 / Thursday, September 7, 2023 / Proposed Rules 

159See infra Section VI.A. 

160Millis, W. (2021). An Improvement to the 

THOR–50M Upper Leg Qualification Test 

Methodology. 2021 SAE Government-Industry 

Digital Summit, available at: https://

www.nhtsa.gov/node/103666. 

161National Highway Traffic Safety 

Administration (2022). THOR–50M Repeatability 

and Reproducibility of Qualification Tests, May 

2021, available at https://downloads.

regulations.gov/NHTSA-2019-0106-0009/ 

attachment_2.pdf. We note that for the sled test 

R&R analysis, there are no previously-published 

reports that provide this analysis. However, this 

analysis is provided in the paragraphs below on 

sled testing (and in the relevant appendices) and 

the underlying data is available in the NHTSA crash 

test database in either the biomechanics or vehicle 

paragraphs (the specific location is provided in the 

relevant discussion below). 

162NHTSA did not examine lab-to-lab 

reproducibility of the sled tests. 

(CVs) 159 above 10%, particularly for the 

peak resultant acetabulum force. 

NHTSA therefore conducted a detailed 

review of the qualification test 

procedure.160 This review led NHTSA 

to conclude that the impact energy was 

unrealistically low, leading to two 

problems. First, the low test energy did 

not load the acetabulum at a magnitude 

similar to that produced in vehicle crash 

tests or associated with a meaningful 

injury risk. This is particularly 

important because the upper leg test 

mode is the only qualification test that 

assesses the acetabulum load cells, and 

peak resultant acetabulum force is used 

in calculating the acetabulum injury 

risk. Second, and relatedly, the 

measurement values were so low, it was 

difficult to distinguish the signal from 

the noise. 

Accordingly, NHTSA revised the test 

parameters by increasing the impactor 

mass and velocity and installing a 

backer plate behind the pelvis to 

prevent any rearward motion during the 

test. These are the parameters that we 

are proposing and for which data is 

presented (and acceptance intervals 

calculated) in the qualification 

repeatability and reproducibility study. 

As we explain in Section VI.A, the 

revised test procedures resulted in 

repeatability and reproducibility CVs of 

5% or lower for all test measurements 

including peak resultant acetabulum 

force. Additionally, the average 

acetabulum force recorded in the 

improved upper leg qualification is 

more representative of the forces 

recorded in frontal rigid barrier and 

OMDB vehicle crash tests, and 

represents a non-negligible injury risk. 

H. Knee and Lower Leg 

NHTSA is also proposing 

qualification tests for the knee and 

lower leg (ankle, ball of foot, and heel). 

The knee qualification test is a 

simplification of the knee shear 

biofidelity condition. The test assesses 

the response of the anterior-posterior 

translation of the tibia with respect to 

the femur at the knee joint, the 

translational resistance of the knee 

slider and the stiffness of the stop 

assembly, and the functionality of the 

knee slider string potentiometer. To 

conduct the knee impact test, the left or 

right knee assembly (detached at the 

base of the femur load cell) is removed 

from the ATD and mounted to a rigid 

surface, and a load distribution bracket 

is attached to the knee slider assembly. 

The load distribution bracket is 

impacted with a 12.00 kg impactor with 

a 76.2 mm diameter rigid disk impact 

surface at 2.20 ± 0.05 m/s. Unlike the 

HIII–50M knee slider test, no foam pad 

is used on the impact surface for this 

test. During these tests, the femur Z-axis 

force and knee slider deflection at peak 

femur force are measured and would 

have to be within the proposed 

acceptance intervals. 

We propose four different 

qualification tests to assess the lower leg 

responses: ankle inversion, ankle 

eversion, ball of foot impact, and heel 

impact. All four test setups are similar. 

In each, the lower legs are removed from 

the dummy and each leg is tested 

separately. The leg is affixed to a rigid 

fixture and struck by a pendulum 

parallel to the tibia. The alignment of 

the pendulum differs for each test: for 

the heel impact, it is in-line with the 

tibia; for the ball of foot impact, it 

produces dorsiflexion of the foot; for the 

inversion impact; it is offset medially 

from the tibia; for the eversion impact, 

it is offset laterally from the tibia. For 

the inversion and eversion impacts, the 

shoe is removed and replaced with a 

special striker plate that interfaces with 

the pendulum. 

Euro NCAP TB026 specifies different 

qualification requirements for the knee 

and lower leg because TB026 specifies 

that the THOR–50M be fitted with the 

HIII–50M knee and lower leg. 

VI. Repeatability and Reproducibility 

Any ATD that is to be used for 

Federal regulatory testing must have an 

acceptable level of repeatability and 

reproducibility to ensure confidence in 

the responses provided by the dummy. 

In the context of dummy evaluation, 

repeatability refers to the similarity of 

responses from a single dummy when 

repeatedly subjected to a particular test 

condition. Reproducibility refers to the 

similarity of the responses from 

multiple dummies repeatedly subjected 

to a particular test condition. NHTSA 

also evaluated the repeatability and 

reproducibility of the qualification tests 

themselves, in addition to the dummy. 

To evaluate whether the THOR–50M 

ATD yields consistent results, NHTSA 

undertook an extensive series of testing. 

NHTSA systematically investigated 

the repeatability and reproducibility 

(R&R) of the THOR–50M by conducting 

an extensive series of qualification and 

sled tests. Qualification test 

measurements are especially useful for 

evaluating dummy R&R because they 

are relatively simple tests on individual 

dummy components that can be tightly 

controlled so that variability in the test 

measurements is more likely to come 

from the dummy than from other 

potential sources of variability, such as 

the test procedures or vehicle structures 

and materials. Sled testing is useful 

because it offers insight into the 

dummy’s performance as a complete 

system in an environment similar to that 

of an actual vehicle—e.g., the 

consistency of its kinematics, its impact 

response as an assembly, and the 

integrity of the dummy’s structure. Sled 

tests are therefore more challenging for 

the dummy, while at the same time 

much more tightly controlled than a 

vehicle test, which does not provide a 

desirable environment for R&R testing 

due to the uncontrollable variation in 

vehicle structural materials and 

manufacturing variability. Qualification 

and sled tests together provide a basis 

for assessing whether the dummy will 

yield consistent results when it is 

ultimately used in full-scale vehicle 

tests. NHTSA’s R&R testing also served 

several other important functions, such 

as developing the qualification corridors 

and further validating the usability and 

durability of the dummy. 

NHTSA’s R&R analysis of 

qualification and sled testing is briefly 

summarized in the next two sections. 

For more detailed information, the 

reader is referred to the docketed report 

‘‘THOR–50M Repeatability and 

Reproducibility of Qualification Tests’’ 

(R&R Report).161

A note about dummy reproducibility: 

At the time NHTSA conducted this R&R 

testing (both qualification tests and sled 

tests) it only owned—and tested— 

THOR–50M units manufactured by 

Humanetics. Therefore, the 

reproducibility analyses reported here 

concerned dummy reproducibility 

(same lab, different dummies) and test 

reproducibility (same dummy, different 

labs).162 However, another aspect of 

reproducibility is whether dummies 

fabricated by different manufacturers 

perform in a uniform manner. To this 

end, NHTSA has purchased THOR–50M 

units from JASTI, Cellbond, and Kistler, 


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163 40 FR 33466 (Aug. 8, 1975). 

164See, e.g., 85 FR 69898, 69904–69905 (Nov. 3, 

2020) (final rule for Q3s ATD). 

165The population-based standard deviation, 

which is always lower than the sample-based 

standard deviation, is not appropriate because only 

a limited number of NHTSA-owned THOR–50M 

units were tested, and the tests were carried out at 

a limited number of test facilities. 

and may test with these units prior to 

the final rule. 

A. Qualification Tests 

NHTSA has completed an R&R study 

of the qualification tests. This study has 

three main purposes. One is to assess 

the repeatability and reproducibility of 

the dummy. Another is to determine the 

acceptance intervals for the 

qualification tests. Third, is to assess the 

R&R of the qualification tests 

themselves. Assessing the R&R of the 

qualification tests is important for at 

least two reasons: it aids in determining 

whether the variation in measurements 

are attributable to the dummy, the test 

procedures, or the testing practices of 

different laboratories, and it helps 

ensure that the qualification test 

procedures themselves are as consistent 

and replicable as possible so that, 

ultimately, the test measurements 

obtained in a compliance test are 

uniform across dummies and test 

laboratories. In addition to these main 

purposes, the qualification R&R testing 

also helped NHTSA to identify and 

resolve potential issues with the 

qualification procedures; reveal and 

resolve potential issues with, and 

functional limitations of, the dummy. 

Below, we first summarize our 

methodology for the qualification R&R 

analysis, and then proceed to briefly 

summarize the results of the R&R 

assessment for each THOR–50M body 

region. 

Methodology 

The proposed qualification tests were 

carried out on three THOR–50M ATDs 

manufactured by Humanetics. The 

ATDs conformed to the proposed 

drawing package. Every ATD was 

subjected to five repeat tests in each 

qualification test condition at NHTSA’s 

Vehicle Research and Test Center 

(VRTC) and one of the three dummies 

was tested at two other labs, 

Humanetics and Calspan (with some 

exceptions as described in the following 

paragraphs). All tests were used in 

development of the proposed 

qualification acceptance intervals, with 

some exceptions as explained below 

where the input velocity did not meet 

the specification. For qualification test 

conditions where one ATD component 

is tested in both the left and the right 

direction, only the left direction is 

included in the analysis, as the dummy 

design is symmetric and not expected to 

differ between the two sides. For 

qualification test conditions in which 

multiple ATD components are tested, 

data from the left and right tests or 

measurements are combined. 

We evaluated R&R of both the dummy 

and the qualification tests using a 

statistical analysis of variance referred 

to as the coefficient of variation (CV). 

The CV approach was first introduced 

by NHTSA as a means for evaluating 

dummy repeatability when the original 

subpart B Hybrid II 50th percentile male 

ATD was proposed.163 Since then, the 

agency has used this approach for other 

Part 572 rulemakings.164 The CV is a 

measure of variability expressed as a 

percentage of the mean. It is defined as 

the percentage of the sample standard 

deviation divided by the mean of the 

data set: 

In the qualification test series, the 

data points of each trial are considered 

on their own and not as being 

representative of a large population. 

Thus, the sample-based standard 

deviation is applied in which s is an 

estimate of the standard deviation based 

on a sample.165 It is computed using the 

following formula, where x ̄ is the 

average value of the trials (sample 

mean) and n is the number of trials 

(sample size). 

For each qualification test parameter 

(e.g., head impact peak probe force) 

specified for each test condition (e.g., 

head impact), we computed the mean, 

standard deviation, and coefficient of 

variation. More specifically, to 

investigate dummy repeatability and 

test repeatability, we calculated these 

summary statistics for the five tests of 

each test condition performed on each 

of the three dummies at VRTC. To 

investigate dummy reproducibility, we 

pooled the data for the three dummies 

tested at VRTC. Finally, to investigate 

test reproducibility, we pooled the data 

for the dummy that was tested at VRTC, 

Calspan, and Humanetics. 

We used the following approach to 

assess R&R: 

• CV <5%: No further investigation. 

We believe that a set of responses with 

a CV below 5% indicates a highly 

repeatable and reproducible condition. 

• 5% ≥ CV ≤ 10%: sources of 

variability investigated. 

• CV >10%: Test procedure 

thoroughly reviewed and dummy(ies) 

inspected. 

When the CV was greater than or 

equal to 5%, we investigated the source 

of the variability. In all cases, we were 

able to determine the source of the 

variation with reasonable confidence. 

Once NHTSA had refined the 

qualification test procedures it only 

obtained a CV greater than 10% in two 

instances—repeatability of the face 

foam, and test reproducibility in one 

measurement in the neck extension 

mode. Prior to refining the test 

procedures, NHTSA obtained a CV 

greater than 10% for the upper leg test. 

A full investigation led to a new and 

improved test procedure. That new test 

procedure is reflected in the R&R report, 

and the resulting CVs all less than 10%. 

Table 9 and Table 10 summarize the 

CVs that we calculated for each test 

parameter for each qualification test 

condition. Table 11 summarizes the 

variability sources and resolutions seen 

in the qualification R&R test series. 

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166This is seen in the head impact test series, in 

which the headskins were found to be repeatable 

and reproducible, with repeated impacts to the 

head yielding nearly identical responses. 

BILLING CODE 4910–59–C 

TABLE 11—SUMMARY OF QUALIFICATION TEST VARIABILITY SOURCES AND RESOLUTIONS

Test mode Source of varibility; control solution 

Head ..................................... None. 

Face ..................................... Face foam degradation occurs cumulatively with successive impacts; monitor and swap out foam as needed. 

Neck Extension .................... The inverse relationship between My and Fz may be balanced by adjusting the input pulse through the selection 

of the pendulum’s honeycomb cell configuraton. 

Neck Flexion ........................ For a new molded neck, My and Fz may be elevated in initial test only. Also, the pendulum’s honeycomb cell 

configuration may need attention to control input pulse. 

Neck Lateral ......................... None. 

Neck Torsion ........................ None. 

Upper Thorax ....................... None. 

Lower Thorax ....................... The asymmetric test setup requires a high level of diligence from operator in aligning the dummy with the probe. 

Abdomen .............................. Operator diligence is needed to ensure a symmetric test setup. Otherwise, right vs. left discrepancies in force and 

deflection measurements will occur. 

Upper Leg ............................ If a high femur Fz occurs, a test lab may need to experiment with set-ups and dummy positioning (within allowable tolerances). 

Knee ..................................... Low femur Fz measurements may be resolved at the test labs by experimenting with setups and dummy positioning. 

Ankle Inversion .....................

Ankle Eversion .....................

Ankle inversion and eversion tests are run on the same apparatus and are nearly identical. The ankle moment, 

tibia Fz, and ankle rotation may be slightly low in an initial qualification test if there has been an extended period of non-use of the Ensolite pad on the test fixture. This is only a concern if the tibia force and moment are 

just below the upper qualification limits, since subsequent tests may be expected to produce slightly higher moments and forces (which might be out of the qualification range). Labs can simply perform an additional test to 

confirm that the response of the ankle is within the requirements. 

Ball of Foot ........................... Test labs may need to adjust their set-ups and fixtures (within allowable tolerances) to attain a reponse within 

10% of the target for ankle moment. 

Heel ...................................... In cases where passing qualification results cannot be achieved, a test lab may need to replace the molded shoe 

assembly (472–7800–1 (left) or –2(right)) and/or the upper tibia complaint bushing assembly (472–7315) in 

order to attain a peak lower tibia Fz within 10% of the target. 

Our investigation of the sources of 

variability also gives us additional 

confidence that the proposed 

acceptance intervals (± 10% of the mean 

response reported in the R&R study) are 

both achievable and sufficient to ensure 

that the dummy is providing uniform 

responses. In NHTSA’s testing, when 

the CV was below 5%, the responses in 

all the tests were always within the 

proposed acceptance intervals. When 

the CV exceeded 5%, however, we 

observed a response outside the 

proposed acceptance interval in at least 

one test. When the CV exceeded 10%, 

several tests were outside the 

qualification corridor. 

NHTSA seeks comment on this 

methodology. Although the 

qualification R&R study utilizes only 

NHTSA’s test data, NHTSA is open to 

considering qualification data provided 

by commenters in the finalization of the 

qualification specifications, provided 

that the data are from THOR–50M ATDs 

conforming to the 2023 drawing package 

and collected following the proposed 

Qualification Procedures. 

Head Impact 

In the head impact qualification test 

mode, all CVs for repeatability and 

reproducibility were below 5%, and the 

responses in all the tests were within 

the proposed qualification acceptance 

intervals. 

Face Impact 

We used a slightly different approach 

to evaluating the R&R of the face than 

we did for the other qualification tests. 

Our approach was motivated by two 

characteristics of the THOR–50M face. 

First was the response of the face 

foam. The impact response of the face 

is driven primarily by the face foam 

insert, which is constructed of a 

memory foam that necessitates an 

extensive recovery period after a 

dynamic impact; the THOR–50M 

Qualification Procedures specifies at 

least 24 hours of recovery between tests. 

Even with this extended recovery 

period, however, the foam progressively 

degrades after each impact so that the 

peak probe force and peak head 

resultant acceleration increases with 

each test. We were able to conduct eight 

to nine tests with a new face foam insert 

before the face fell outside the upper 

bound of the face rigid disc impact 

biofidelity corridor (4,400 N to 8,200 N). 

Second, because the face foam 

degrades, any variations in the dummy 

response are likely to be masked by the 

significant variations caused by the 

foam. That is, most of the observed 

variation in the face qualification test is 

essentially due to the face foam 

response; any contributions of other 

components or lab-to-lab differences 

were negligible.166

In light of these characteristics, we 

modified the R&R test methodology for 

the face impact tests. Our testing 

consisted of evaluating one dummy 

(DO9799) at VRTC, using three different 

new, unused, face foams (as opposed to 

testing three different ATDs); we 

deemed it unnecessary to test multiple 

ATDs because the variation in response 

was predominantly due to the face 

foam, not the ATD. We also did not test 

lab-to-lab variability (test 

reproducibility), because this would 

require testing the same face foam 

successively at multiple laboratories, 

which the degradation of the face foam 

prevented us from doing. We allowed 24 

hours between tests as specified in the 

Qualifications Procedures. We tested 

each dummy until the peak probe force 


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167R&R Report, Table 6–14. 

168Upper neck Fz is currently specified in FMVSS 

NO. 208 as an injury criterion for the HIII–50M and 

is also a component of THOR-specific Nij criterion. 169R&R Report, Table 7–16. 

fell out of the biofidelity corridor (until 

the peak probe force exceeded 8,200 N). 

Only those tests which fell within the 

peak probe force biofidelity corridor 

were then included in the repeatability 

analysis and used to set the 

qualification targets. This gave us eightto-nine tests for each of the three face 

foams we tested. 

For two of the face foam inserts 

tested, repeatability CVs were below 

10%. The third face foam insert resulted 

in CVs for peak probe force and peak 

head CG resultant acceleration of 10.1% 

and 12.1%. Though not reported in the 

R&R paper, CVs for the HIC15 values 

associated with the head resultant 

accelerations recorded in the face 

impact test are within 1% of the CVs for 

peak resultant head CG acceleration. 

However, in practice, we would likely 

not observe this level of variability 

because in several of the tests used to 

calculate CV, the peak probe force was 

outside of the qualification targets 

(either too high or too low) and so the 

dummy would have been further 

adjusted before being used in a 

compliance (or research) test. We 

observed that when the response of a 

new face foam insert is too low, it likely 

indicates the need for an additional 

‘‘break in’’ test, in which case the face 

impact test would be repeated. If the 

response is too high, it likely indicates 

that the face foam needs to be replaced, 

in which case a new face foam insert 

will be installed and the face impact test 

repeated. Therefore, we believe that the 

face impact test is sufficiently 

repeatable. Moreover, although we did 

not test at multiple labs to evaluate 

reproducibility due to face foam 

degradation, we also believe that the 

face impact test is reproducible. The 

head impact test uses essentially the 

same test apparatus and a similar 

impact condition as the face impact test. 

Because the test reproducibility was 

very good in the head impact test, we 

expect that there will be acceptable 

levels of lab-to-lab variability for the 

face impact test as well. 

Neck 

For the neck qualification tests, the 

entire head-neck assembly is removed 

from the THOR–50M, so the serial 

numbers listed in Table 9 are those of 

the individual head-neck assemblies 

and not the ATD itself. 

With respect to repeatability, across 

all four neck test modes (flexion, 

extension, lateral flexion, and torsion), 

CVs for repeatability were below 10% 

for all qualification test parameters and 

for all necks, and were below 5% except 

in the neck flexion test mode for two of 

the necks: peak upper neck Y-axis 

moment (5.8%) and peak upper neck Zaxis force (6.0%) for neck EB6007, and 

peak upper neck Y-axis moment for 

neck EB6006 (5.1%). For both of these 

necks, the first test resulted in a peak 

upper neck Y-axis moment higher than 

the resulting qualification targets; thus 

this first test would have been re-run in 

practice. If this first test were discarded, 

the resulting repeatability CVs would be 

at or below 5% for all necks. Labs may 

find that while the first neck flexion test 

performed on a new neck produces a Yaxis moment greater than the 

qualification targets, subsequent tests 

result in lower values within the 

acceptance interval. Also, labs may need 

to adjust the input pulse by 

experimenting with honeycomb cell 

configurations to achieve the target 

response. 

Reproducibility CVs were below 5%, 

except in four instances, two for the 

neck flexion test mode, and two for the 

neck extension test mode. 

In the neck flexion test mode, the 

dummy reproducibility CV for peak 

upper neck Y-axis moment was 5.4%. 

This likely results from the same breakin issue described above. Also in the 

neck flexion test mode, the test 

reproducibility CV for peak upper neck 

Z-axis force was 7.5%. In this case, 

there were two tests each at Calspan and 

Humanetics that would not have met 

the resulting qualification 

specifications,167 though discarding 

these tests would still result in a 

reproducibility CV of 6.4% for peak 

upper neck Z-axis force. However, we 

believe that this variance is not likely to 

lead to inconsistent compliance test 

outcomes because the average peak 

upper neck Z-axis force (860 N) 

represents a very low probability of 

injury (0.7% risk of AIS 3+ injury). 

Although NHTSA has not yet 

established injury assessment reference 

values (IARVs) for the THOR, when it 

does (NHTSA anticipates rulemaking in 

the near future to add the THOR–50M 

to FMVSS No. 208 as an optional test 

device) an IARV for neck flexion would 

almost certainly be specified to 

correspond to a risk of AIS 3+ injury 

much higher than 0.7%, i.e., 

corresponding to a much higher Z-axis 

force than 860 N.168

In the neck extension test mode, two 

test reproducibility CVs were above 5%: 

peak upper neck Y-axis moment (5.6%) 

and peak upper neck Z-axis force 

(12.2%). These elevated CVs result from 

the tests on neck EB6007 at Calspan, for 

which the first four tests resulted in 

peak upper neck Z-axis forces lower in 

magnitude than the resulting 

qualification targets, while the last test 

resulted in a peak upper neck Y-axis 

moment higher in magnitude than the 

resulting qualification targets, and at 

Humanetics, for which four of the five 

tests resulted in peak upper neck Z-axis 

forces higher in magnitude than the 

qualification targets, though by not more 

than 32 N.169 However, since all of the 

remaining tests on neck EB6007 at 

VRTC (15 tests) would have met the 

qualification targets, and the associated 

test reproducibility CVs would be below 

3% for all test parameters except for the 

Calspan observations, this finding likely 

results from either an issue with test 

execution at Calspan, or an issue 

specific to neck EB6007, such as damage 

or unintended adjustment of the neck 

spring cables after it was tested at both 

VRTC and Humanetics. 

While the input parameters for the 

tests conducted on EB6007 were all 

within the qualification specifications, 

the pendulum velocity at 20 and 30 

milliseconds after T-zero was notably 

higher at Calspan compared to VRTC 

and Humanetics, which may explain the 

differences in results. As such, it may be 

worth considering narrower 

specifications on the pendulum velocity 

input parameters. On the other hand, if 

the differing results at Calspan resulted 

from issues with the neck itself, then the 

fact that the qualification specifications 

were not met indicates that the 

qualification tests successfully 

identified a damaged or improperly 

configured neck. 

Upper Thorax 

In the upper thorax qualification test 

mode, all CVs for repeatability and 

reproducibility were below 5%, which 

indicates that the qualification 

specifications were achievable by three 

different THOR–50M ATDs and at three 

different test labs. Further, as all CVs 

were below 3.7%, this indicates that all 

tests were within the ±10% target. 

Lower Thorax 

In the lower thorax qualification test 

mode, all but one of the CVs for 

repeatability were below 5%. One 

repeatability assessment, peak resultant 

deflection at peak probe force for ATD 

DO9798, had a CV of 5.2%. For this 

ATD, peak resultant deflections on the 

right side were closer to the upper end 

of the corridor, while those on the left 

side were closer to the lower end of the 

corridor. CVs for dummy 

reproducibility were below 5%. Test 


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170R&R Report, Table 11–9. 

reproducibility CVs were slightly above 

5%. Here, one of the tests at Humanetics 

would not have met the resulting peak 

probe force qualification specifications, 

while four of the tests at Calspan would 

not have met the resultant deflection at 

peak force specification.170 If the tests 

that would not fall within the 

qualification specifications were 

excluded, as would be done in practice, 

reproducibility CVs would be below 

5%. Overall, the lower thorax 

qualification specifications were 

achievable by three different THOR– 

50M ATDs and at three different test 

labs. 

Abdomen 

When the abdomen qualification 

repeatability and reproducibility testing 

was conducted, all three THOR–50M 

ATDs were not available. 

As an alternative, three different 

abdomen assemblies were tested on the 

same ATD. We believe this modification 

is acceptable because the abdomen foam 

inserts and the structure of the abdomen 

bag are responsible for a majority of the 

variation in the lower abdomen 

qualification test, whereas the 

remainder of the THOR–50M is 

essentially a ballast. 

All of the CVs for repeatability and 

reproducibility of peak probe force were 

below 5%. All of the CVs for 

repeatability and reproducibility of the 

peak left and right X-axis deflection at 

the time of peak force were between 5% 

and 6%. Of these tests, three at Calspan 

resulted in right abdomen X-axis 

deflections lower in magnitude than the 

qualification specifications. While not 

included in the CV calculation, the 

difference between left and right X-axis 

deflection measurement highlighted the 

fact that all tests at VRTC had a positive 

difference of at least 6.8 millimeters, 

indicating that the magnitude of right Xaxis deflection was greater than the 

magnitude of left X-axis deflection in all 

tests. The opposite was true at Calspan, 

where three of the tests showed notably 

higher magnitude deflections on the left 

side. In total, six of the abdomen 

qualification tests (five at VRTC and one 

at Calspan) were beyond the 8 

millimeter difference specified by the 

qualification specifications. Further 

examination of the test setup at VRTC 

showed that the ATD was consistently 

rotated slightly about the Z-axis, 

resulting in the right side of the 

abdomen being closer to the probe than 

the left side, and subsequently recording 

more deflection. The test configuration 

at VRTC has since been corrected. This 

issue is not expected to introduce 

variability in test results in the future 

because such tests outside the 

qualification targets would necessitate 

dummy adjustment and re-running the 

test. If only tests that were within the 

maximum difference in left-to-right 

deflection specification were included, 

both the dummy and test 

reproducibility CVs would be 5.0% or 

below. 

Upper Leg 

As we explained earlier (Section VI, 

Qualification Tests), the proposed upper 

leg qualification test procedure reflects 

revisions to the 2018 Qualification Test 

Procedures that we made in light of our 

R&R testing. The CVs for repeatability 

and reproducibility for the revised test 

procedure for all three measurements 

were at or below 5%, demonstrating that 

the upper leg qualification 

specifications can be met by three 

different THOR–50M ATDs at three 

different test labs. 

Knee 

For the knee qualification test, all CVs 

for repeatability were below 5%. For 

dummy reproducibility, CVs were 5.0% 

and below for both measures. For test 

reproducibility, the CV for knee 

deflection at peak femur Z-axis force 

was below 5%, while the CV for peak 

femur Z-axis force was 5.9%. This 

elevated CV appears to result from the 

tests at Calspan, which were all 

generally lower in magnitude than at 

VRTC and Humanetics, and three of the 

tests resulted in peak femur Z-axis force 

lower than the qualification 

specification. As the three tests that 

were outside of the qualification 

specifications were the first or second 

tests in the series, it is possible that the 

lower forces resulted from misalignment 

of the load distribution plate or other 

slack in the system that was corrected 

in the remaining tests. In light of this, 

we believe that the knee qualification 

repeatability and reproducibility test 

series demonstrated that the 

qualification specifications could be 

achieved by six different THOR–50M 

knees at three different test labs. 

Lower Leg 

As used by VRTC, the lower legs are 

considered modular, and are typically 

assigned to a THOR–50M on 

deployment and not necessarily tied to 

a specific THOR–50Ms serial number. 

As such, the repeatability and 

reproducibility qualification study was 

carried out by testing three different 

lower legs at VRTC, followed by testing 

two of those legs at both Humanetics 

and Calspan. This resulted in a total of 

15 tests for the dummy reproducibility 

assessment, and 30 tests for the 

reproducibility assessment (although 

several of the tests at Calspan were not 

included because they did not meet the 

test velocity input specifications). 

For all the lower leg test modes, 

repeatability CVs were all below 5%, 

indicating that the qualification 

specifications are achievable by three 

different THOR–50M ATDs. There were, 

however, a few test mode/parameters for 

which reproducibility CVs were above 

5%. 

In the ankle inversion test mode, test 

reproducibility for the peak lower tibia 

Z-axis force measurement was 5.3%. 

The source of this elevated CV appears 

to be the first test of leg DL5405 at 

VRTC, where the peak lower tibia Z-axis 

force was ¥451 N, which was just 

outside the acceptance interval (¥454 

to ¥555 N). In practice, this test would 

have been re-run, and all the remaining 

tests on this leg would have met the 

qualification targets. Removing this test 

from the CV calculation would result in 

a test reproducibility CV of 4.9%. 

In the ankle eversion test mode, 

dummy reproducibility was above 5% 

for the peak lower tibia Z-axis force 

(5.7%), and test reproducibility was 

above 5% for lower tibia Z-axis force 

(6.0%) and peak ankle resistive moment 

(5.1%). These elevated CVs appear to 

result from the first tests on DL0202 at 

VRTC, where the peak lower tibia Z-axis 

force (¥512 N) was just outside the 

acceptance interval (¥514 N to ¥629 

N), and at Calspan, where the peak 

lower tibia Z-axis force (¥454 N) and 

the peak angle resistive moment (35.6 

Nm) were both below the lower end of 

the associated qualification 

specifications (¥514 N and 38.7 Nm, 

respectively). In practice, these tests 

would have been re-run, and all the 

remaining tests on this leg at both labs 

would have met the qualification 

specification. Removing these two tests 

from the CV calculation would result in 

reproducibility CVs all below 5%, 

which demonstrates that the ankle 

eversion qualification specifications can 

be met by six different legs at three 

different test labs. 

In the ball-of-foot test mode, which 

assesses both the impact response of the 

ball-of-foot portion of the molded shoe 

and the dorsiflexion response of the 

ankle, the only CV above 5% was the 

test reproducibility of the peak ankle 

resistive moment (6.9%). In the tests at 

Calspan, only two of the five tests on the 

left leg (DL0202) met the qualification 

specification for input velocity. The 

three tests that did not meet the 

qualification specification were 

considered invalid tests and therefore 

were not included in the test 


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reproducibility assessment, so only 

seven tests from Calspan were included 

as opposed to 10 tests from each of the 

other labs. Of the tests run by Calspan 

on the right leg (DL5404), four of the 

five resulted in peak ankle resistive 

moments of 61.3 to 61.8 Nm, just above 

the upper end of the qualification 

specification (60.8 Nm). As the tests at 

Calspan were consistently higher in 

peak ankle resistive moment than those 

at VRTC and Humanetics, it is possible 

that this finding results from either an 

issue with test execution at Calspan, or 

an issue specific to leg DL5404, such as 

damage or unintended adjustment of the 

Achilles spring cables after it was tested 

at both VRTC and Humanetics. 

Reviewing the time-history data for 

ankle resistive moment from exemplar 

tests from Calspan, VRTC, and 

Humanetics (Figure 1), there are some 

differences early in the event (note the 

large positive moment before 10 

milliseconds in the Calspan test) that 

suggest differences in test setup and/or 

impactor hardware. 

In the heel impact test, which assesses 

both the impact response of the heel 

portion of the molded shoe and the tibia 

compliant element, the repeatability 

CVs were all under 5%, but both the 

dummy (6.4%) and test (5.9%) 

reproducibility CVs were over 5%. If the 

test CVs are calculated independently 

for the left and right legs, the resulting 

CVs are much lower (2.1% and 3.0%, 

respectively). This suggests that the test 

itself is repeatable (as all repeatability 

CVs were 1.6% or below) and 

reproducible, but that there is some 

ATD-to-ATD (in this case, leg-to-leg) 

variation. Nonetheless, the qualification 

specifications for the heel impact test 

can be met using three different legs in 

at least two different test labs. 

Additional Qualification Test Lab 

We performed a variety of vehicle 

tests (discussed in Section VIII, Overall 

Usability and Performance) where 

multiple dummies were qualified at two 

different labs, including a lab (Applus+ 

IDIADA KARCO Engineering LLC) that 

was not one of the laboratories used to 

develop the qualification specifications, 

and it was possible to qualify the 

dummies. This qualitative information 

gives us further confidence that the 

qualification tests are reproducible. 

Therefore, NHTSA tentatively 

concludes that there is a sufficiently 

high degree of uniformity in the 

construction of the dummy components 

being tested and in the procedures 

followed by the labs for that test 

requirement for the THOR–50M to be 

incorporated into Part 572. 

B. Sled Tests 

THOR–50M repeatability was also 

assessed through sled tests representing 

several different vehicle crash 

environments, including unbelted, 

standard, and load-limited three-point 

belt configurations at different speeds 

for both the driver and right front 

passenger seating positions, as well as 

several restraint configurations in the 

rear seat. NHTSA’s sled test 

repeatability analysis is based on data 

from three different sled test series that 

NHTSA ran in the course of developing 

THOR–50M. One is a sled test series 

conducted to develop thoracic injury 

criteria for the THOR–50M. Another is 

a sled test series conducted to assess the 

performance of THOR–50M in lowspeed belted crashes. The third is a sled 

test series conducted to assess THOR– 

50M’s performance in low-speed 

unbelted crashes. 

In summary, while there were several 

cases where the variation from test to 

test of the same THOR–50M ATD was 

greater than 10%, these cases can be 

explained by either differences in 

physical interactions (e.g., contact of the 

head with the arm in the rear seat sled 

test), which can be addressed by careful 

pre-test positioning of the ATD, or by 

the low magnitude of the measurements, 

as demonstrated through the use of 

normalized CV to identify cases where 

the variation occurs at a much lower 

level than would be associated with a 

risk of injury. 

This is discussed in more detail in the 

sections that follow. We begin by 

explaining our methodology, and then 

proceed to discuss the three different 

test series. 

1. Methodology 

As with the qualification R&R 

analysis, we assessed repeatability using 

the coefficient of variation. The CVs 

were calculated for each of the injury 

criteria described in the THOR–50M 

injury criteria report, as well as for peak 


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171The low-speed sled tests have fewer metrics 

than the thoracic injury criteria set (11 vs. 12) 

because lower shoulder belt loads were not 

recorded in the low-speed sled tests. 

172This differs from the qualification tests, for 

which it is known that the data set is a sample of 

a larger population (because NHTSA and other test 

labs have run the qualification tests on other 

THOR–50M ATDs). 

173Fifty percent risk of a given injury severity is 

a widely-used tolerance level in ATD research. 

IARVs specified in the FMVSS may or may not 

correspond to a 50% risk. 

174We used the shoulder belt force to normalize 

the lap belt force because there was not meaningful 

lap belt force data in some of the thoracic injury 

criteria development test conditions. 

values from a few other key data 

channels: 171 lap belt, upper shoulder 

belt, and lower shoulder belt. 

The CV analysis was the same as in 

the qualification test R&R study, with 

two modifications. As with the 

qualification test R&R study, CVs below 

5% were considered to require no 

further investigation; for CVs between 

5% and 10% we reviewed the results for 

outliers; and for CVs greater than 10% 

we thoroughly investigated the sources 

of variability in the test procedure and 

the ATD. However, our assessment 

differed in two ways from the CV 

assessment in the qualification R&R 

study. 

First, we used the population 

standard deviation instead of the sample 

standard deviation to calculate the CV 

because these test series are the only 

sled test series that have been run.172

Accordingly, 

Second, in addition to the CVs we 

also considered the normalized CVs. A 

potential limitation of the CV 

calculation is that when the magnitude 

of a given measurement is relatively 

low, as is the case with off-axis sensor 

channels, the standard deviation can be 

high relative to the mean, leading to CVs 

over 10%. However, this result is not 

necessarily meaningful: although the 

amount of variation might be high 

relative to the mean, it might not be 

high with respect to say, a critical value 

of the measurement being evaluated 

(e.g., in the context of a compliance test 

involving an ATD, it might not be high 

with respect to the IARV). This was 

generally not an issue in the 

qualification test R&R analysis because 

the qualification modes, test parameters, 

and targets were all selected because 

they are meaningful to the test mode 

and/or are in the primary load path, so 

that the resulting measurements were 

generally of sufficient magnitude for a 

reliable CV calculation. In sled and 

vehicle crash tests, on the other hand, 

it is not known in advance which sensor 

channels will be of sufficient magnitude 

for a reliable CV assessment. For this 

reason, researchers often disregard high 

CV values when the magnitude of the 

measurement is relatively low. 

However, determining the level of the 

measurement below which CV is not 

reliable is inherently subjective. 

Accordingly, for CVs above 10% we 

also considered normalized CVs. To 

calculate normalized CV, the mean (m) 

in the CV calculation (Eqn. 1) is 

replaced with a meaningful, predetermined reference value. Such a 

reference value could be an IARV or a 

measurement value that corresponds to 

an injury risk similar to the risk that 

would correspond to an IARV. Because 

IARVs for the THOR–50M have not yet 

been finalized, in most cases we 

calculated the normalized CV using the 

value associated with a 50% risk of AIS 

3+ (above the pelvis) or AIS 2+ (below 

the pelvis) injury as the reference 

value.173 However, there is not a known 

risk function that relates belt forces to 

risk of injury, so for this metric we 

normalized using the average shoulder 

belt force from the thoracic injury 

criteria development data set, for which 

just over 50% of the subjects sustained 

AIS 3+ thoracic injuries (a denominator 

of 5,000 N).174 The normalization 

denominators used for each of the 

measurements are shown in Table 12. 

TABLE 12—NORMALIZATION DENOMINATORS FOR CALCULATION OF NORMALIZED CV 

Metric Normalization factor Normalization rationale 

HIC15 ...................................................................................... 1724 ....................... 50% risk of AIS 3+ injury. 

BrIC ......................................................................................... 0.96.

Neck Tension .......................................................................... 4,662 N .................. 50% risk of AIS 3+ injury when used in Nij risk function. 

Neck Compression .................................................................. ¥5,017 N.

Nij ............................................................................................ 1.11 ........................ 50% risk of AIS 3+ injury. 

Chest Peak Res. Defl. ............................................................ 51.4 mm.

Left Femur Axial Force ........................................................... 10,577 N ................ 50% risk of AIS 2+ injury. 

Right Femur Axial Force ......................................................... 10,577 N.

Peak Femur Axial Force ......................................................... 10,577 N.

Lap Belt Force ......................................................................... 5,000 N .................. Average from thoracic injury criteria development data set. 

Upper Shoulder Belt Force ..................................................... 5,000 N.

Lower Shoulder Belt Force ..................................................... 5,000 N.

As an example, consider a repeated 

test with peak femur forces of 500 N, 

1,000 N, and 1,500 N. For these tests, 

the calculated CV would be 41% 

(standard deviation of 408 N divided by 

average of 1000 N), which would 

require a thorough investigation of the 

test procedure and ATD. However, these 

femur forces are all well below 10,577 

N, the force at which 50% risk of AIS 

2+ injury occurs. Thus, calculating a 

normalized CV may provide a more 

meaningful assessment. In this case, the 

normalized CV would be 4% (standard 

deviation of 408 N divided by 50% risk 

of AIS 2+ injury of 10,577 N), which 

would require no further investigation. 

2. Thoracic Injury Criteria Development 

Sled Tests 

One source of data NHTSA looked at 

to further assess repeatability is a sled 

test series conducted to develop 

thoracic injury criteria for the THOR– 

50M. This involved conducting 

matched-pair tests of PMHS and a 

THOR–50M ATD in a variety of sled 


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175Craig, M., Parent, D., Lee, E., Rudd, R., 

Takhounts, E., Hasija, V. (2020). Injury Criteria for 

the THOR 50th Male ATD. Docket ID NHTSA– 

2019–0106–0008, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0008. 

176Our testing included a seventh test condition: 

Far-Side Oblique (representing the right front 

passenger in an oblique moving deformable barrier 

crash test). The THOR–50M setup and positioning, 

however, differed in each of these tests. These tests 

were not valid for the purposes of the repeatability 

analysis, because the differences in setup and 

positioning is expected to—and in fact did—lead to 

a wider variation in results. Specifically, the CVs 

for 8 of the 15 measurements exceeded 10%, with 

most of these over 20%, and some as high as 72%. 

test conditions.175 This series tested the 

same THOR–50M unit in three to four 

repeat tests in each of six different test 

conditions: Gold Standard 1, 2, and 3; 

Rear Standard; Rear Load-limited (Rear 

LL); and Rear Inflatable (Table 13).176

TABLE 13—THOR–50M THORACIC INJURY CRITERIA DEVELOPMENT TEST MATRIX

TSTNO TSTREF 

Nominal test 

speed 

(km/h) 

Test condition name, description 

11117 .........................

11118 .........................

11119 .........................

S0156 

S0157 

S0158 

40 Gold Standard 1: flat rigid seat, standard lap and shoulder belts, knees restrained, 

right front passenger restraint geometry. 

11120 .........................

11121 .........................

11122 .........................

S0159 

S0160 

S0161 

30 Gold Standard 2: flat rigid seat, force-limited shoulder belt and standard lap belt, 

knees restrained, right front passenger restraint geometry.. 

11514 .........................

11515 .........................

11516 .........................

11517 .........................

UVAS0309 

UVAS0310 

UVAS0311 

UVAS0312 

30 Gold Standard 3: flat rigid seat angled 30 degrees counterclockwise, force-limited 

shoulder belt and standard lap belt, knees restrained, right front passenger restraint 

geometry. 

11143 .........................

11144 .........................

11145 .........................

S0199 

S0200 

S0201 

48 Rear Standard: rear passenger in 2004 Ford Taurus buck; 3-point standard belt. 

11140 .........................

11141 .........................

11142 .........................

S0196 

S0197 

S0198 

48 Rear LL: rear passenger in 2004 Ford Taurus buck; 3-point load-limited belt with 

pretensioner. 

11137 .........................

11138 .........................

11139 .........................

S0193 

S0194 

S0195 

48 Rear Inflatable: rear passenger in 2004 Ford Taurus buck; 3-point inflatable force-limited belt with pretensioner. 

Notes: All tests were on THOR–50M S/N 9207. These tests are available in the NHTSA biomechanics database. 

We calculated CVs and normalized 

CVs for each of the injury criteria 

described in the THOR–50M injury 

criteria report, as well as a few other key 

data channels, for a total of 12 metrics 

for each of the six test conditions. See 

Table 14 (CVs) and Table 12 

(normalization denominators). Sixtyfive of the seventy-two CVs calculated 

were below 10%, while seven CVs were 

10% or above. 

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We believe that this data supports our 

tentative conclusion that the THOR– 

50M is sufficiently objective for 

inclusion in Part 572. Almost all the 

CVs were below 10%, and many were 

at or below 5%. For the seven CVs at or 

above 10%, we believe that these do not 

indicate that the dummy does not yield 

repeatable results. These seven 

measurements with CVs above 10% 

were: Gold Standard 1 condition for 

neck compression, Nij, and lap belt 

load; rear-seat standard belt condition 

neck tension; rear-seat load-limited 

condition for BrIC and neck 

compression; and rear-seat inflatable 

belt condition for HIC15). When 

normalized, however, none of these CVs 

were above 10%. This suggests that the 

variability in these measurements 

would not likely lead to variability in 

actual testing outcomes. The variability 

in these measurements is much lower 

than the magnitudes of these 

measurements that would be used as an 

IARV specified in FMVSS No. 208. 

For instance, the individual 

measurements for neck compression in 

the Gold Standard 1 tests were –394 N, 

¥427 N, and ¥328 N. These have an 

average of ¥383 N and a standard 

deviation of 41 N, resulting in an 

unadjusted CV of 11%. While this is 

greater than 10%—potentially 

suggesting that the source of this 

variability needs investigation—these 

measurements are all much lower in 


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177A HIII–50M was seated in the other front 

outboard seat. 

magnitude than the compression force 

that would result in a 50% risk of AIS 

3+ injury (¥5017 N). When the 

standard deviation is compared to this 

compression force instead of the average 

neck compression, we obtain a 

normalized CV of 0.8%. This suggests 

that the magnitudes of the neck 

compression measurements are low 

compared to the magnitude of 

compression that corresponds to a 

meaningful injury risk. 

There was one measurement for 

which the unadjusted CV was below 

10% but the normalized CV was above 

10%: the peak lap belt force in the rearseat inflatable belt condition, which had 

a normalized CV of 11.7%. In this 

instance, the average lap belt load (6,701 

N) was higher than the normalizing 

denominator (5,000 N), resulting in an 

inflated normalized CV. As stated 

earlier, there is not a known risk 

function that relates belt forces to risk 

of injury, so this elevated normalized 

CV is not of particular concern. 

Otherwise, the highest normalized CV 

occurred in the BrIC measurement in 

the rear seat load-limited and 

pretensioned condition (9.6%). This 

appears to result from inconsistent 

initial positioning of the left arm, which 

is more of a test procedure concern than 

a THOR–50M concern. 

3. Low-Speed Belted Sled Tests 

Another source of data NHTSA 

looked at to assess repeatability is a sled 

test series conducted to assess the 

performance of THOR–50M in lowspeed belted conditions. These tests 

were based on the rigid barrier, 

perpendicular impact belted crash test 

specified in FMVSS No. 208 for the 

HIII–50M. Sled tests were conducted at 

crash pulses representing three frontal 

rigid barrier impact velocities (24, 32, 

and 40 km/h) (15, 20, and 25 mph). This 

range of speeds was selected because 

FMVSS No. 208 specifies a speed of up 

to 56 km/h (35 mph) for this crash test, 

and air bag deployment thresholds are 

typically around 24 km/h (15 mph); we 

spanned the 24–40 km/h (15–25 mph) 

range and selected a mid-point of 32 

km/h (20 mph) to conduct a crash test 

and get a crash pulse. In each test, the 

THOR–50M was seated in either the 

driver or right front passenger seating 

locations of a buck representing a midsized passenger car.177 Three tests were 

conducted at each impact velocity, for a 

total of 9 tests. The test buck was 

created from an actual vehicle, and 

included seat belts, front air bags, kneebolsters, and pretensioners. The test 

matrix and additional information about 

the test setup is provided in Appendix 

D. 

As with the thoracic injury criteria 

development test series, both CVs and 

normalized CVs (Table 15) were 

calculated for each of the relevant injury 

metrics described in the THOR–50M 

Injury Criteria Report, as well as femur 

and seat belt loads, for 11 metrics for 

each of the six test conditions. Of these 

66 CVs, 31 were under 5%, 17 were 

between 5% and 10%, and 18 were 

above 10%. 

We believe that this data supports our 

tentative conclusion that THOR–50M is 

sufficiently objective to include in Part 

572. Most of the CVs were under 10% 

and many were under 5%. None of the 

18 measurements for which the CV was 

above 10% had a normalized CV over 

10%, and only five were above 5%. This 

is not surprising, as the low-speed 

belted test condition presents a low 

likelihood of injury. Thus, while there 

may be variations in the injury metrics, 

these variations are small relative to the 

values that would represent a 

meaningful injury risk. 

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4. Low-Speed Unbelted Sled Tests 

Another source of data NHTSA 

looked at to assess repeatability is a sled 

test series conducted to assess the 

performance of THOR–50M in a lowspeed unbelted condition. Sled tests 

were conducted at crash pulses 

representing two frontal rigid barrier 

impact velocities, 32 km/h (20 mph) and 

40 km/h (25 mph), with the THOR–50M 

in both the driver and right front 

passenger seating locations of a test 

buck. Three tests were conducted at 

each impact velocity. The test buck was 

identical to that used in the low-speed 

belted tests except for some minor 

modifications. The test matrix and 

additional information about the test 

setup is provided in Appendix E. 


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As with the thoracic injury criteria 

development and belted test series, CVs 

and normalized CVs were calculated for 

each of the relevant injury metrics 

described in the THOR–50M Injury 

Criteria Report, as well as femur loads, 

for nine metrics for each of the two 

crash pulses. Of these 36 CVs, 12 were 

less than 5%, 20 were between 5% and 

10%, and four were above 10% (Table 

16). 

We believe this supports our tentative 

conclusion that the THOR–50M is 

objective. Almost all the CVs were 

under 10%, and many were under 5%. 

Three of the four measurements with a 

CV over 10% had a normalized CV 

under 10% (neck tension for driver 32 

km/h and RFP 40km/h, and HIC15 for 

RFP 40 km/h), suggesting that the 

variation is small relative to the values 

that would represent a meaningful 

injury risk. The low magnitudes of neck 

tension occur because there is no torso 

restraint in these unbelted tests, so that 

the tension force acting on the neck due 

to the deceleration of the torso is 

minimal (below 500 N). The HIC15

measurements were relatively low 

because the frontal air bags minimized 

the contact of the head with hard 

surfaces or at least decelerated the head 

before contact. The highest average 

HIC15 (360) occurred in the right front 

passenger 40 km/h condition, where 

individual measurements of 309, 349, 

and 423 resulted in a standard deviation 

of 47.3 and a CV of 13.1. 

Only one of those four measurements 

that had a CV over 10% also had a 

normalized CV over 10% (BrIC in the 

Driver 40 km/h condition, 14%). 

NHTSA’s analysis of the test procedure 

and ATD revealed that the variation in 

this case appears to result from a 

difference in head interaction with the 

sun visor and underlying roof structure, 

brought about by small differences in 

the timing and/or position of the head 

at the time of contact. This variation 

could be brought on by initial position 

differences, differences in interaction of 

the pelvis and thighs with the seat 

cushion during initial forward 

translation, or differences in knee 

interaction with the knee bolster and/or 

knee bolster air bag. For additional 

information on this analysis, see 

Appendix E. 

There was one measurement with a 

relatively low CV, but an associated 

normalized CV above 10%. This 

occurred for the Nij measurement in the 


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178 49 CFR 572.137(b). 

driver 40 km/h condition, where the CV 

was 4.7% and the normalized CV was 

10.7%. Because we normalized by the 

value of Nij associated with a 50% 

injury risk, this indicates that the 

average value of Nij from the three tests 

in the driver 40 km/h condition were 

above an Nij associated with 50% risk 

of injury. Closer inspection of the data 

revealed several peaks that cannot be 

explained by the interaction of the 

dummy with the restraint system and 

vehicle interior. This suggests possible 

damage to a load cell or cabling. For 

additional information on this analysis, 

see Appendix E. 

VII. Overall Usability and Performance 

NHTSA’s extensive testing with the 

THOR–50M has also enabled it to assess 

THOR–50M’s overall usability and 

performance. This includes durability, 

ease and frequency of maintenance, and 

how the ATD fits and responds in the 

vehicle environment. We discuss these 

issues in the sections that follow. 

A. Assembly and Qualification 

Based on NHTSA’s experience with 

the dummy at VRTC, assembling the 

THOR–50M following the instructions 

in the PADI takes roughly 80 hours, as 

detailed in Table 17. 

We note that NHTSA treats its THOR– 

50M units not so much as a serialized 

dummy, but as a set of serialized parts 

and sub-assemblies. NHTSA’s THOR– 

50M units typically undergo a routine 

breakdown and inspection after each 

application; when the dummy is 

reassembled, different parts may be 

introduced (for example, if a part 

needed to be refurbished before it could 

be used again). In addition, parts or subassemblies may be taken out of service 

at regular intervals and set aside to 

await preventative maintenance. For 

example, a head and neck sub-assembly 

(both of which are serialized) may be 

taken out of service at regular intervals 

and set aside to await preventative 

maintenance; once clear, the head and 

neck sub-assembly may end up in 

another serialized dummy. Therefore, a 

serialized dummy does not typically 

define the dummy well because 

different parts are constantly being 

interchanged. The parts and assemblies 

which are serialized, either by the 

manufacturer or by NHTSA upon 

delivery of a new ATD or part, are listed 

in Appendix C. 

TABLE 17—ESTIMATED TIME TO

CARRY OUT ASSEMBLY AND ASSOCIATED PROCEDURES DESCRIBED IN

THE THOR–50M PADI 

PADI assembly time 

Body region or procedure Time 

(hrs) 

Head ............................................. 4 

Neck .............................................. 8 

Spine ............................................. 4 

Thorax ........................................... 8 

Shoulder ....................................... 4 

Upper Abdomen ........................... 4 

Lower Abdomen ........................... 4 

Pelvis ............................................ 8 

Upper Leg ..................................... 4 

Lower Extremity ............................ 8 

Arm ............................................... 4 

Jacket and Clothing ...................... 4 

Bundling Cables ........................... 4 

Polarity Check .............................. 4 

Documentation .............................. 8 

Total ....................................... 80 

Based on NHTSA’s experience at 

VRTC, a complete qualification test 

series of 24 tests takes roughly 80 hours, 

assuming that the qualification 

specifications are met (Table 18). If the 

qualification specifications are not met, 

it may take additional time to inspect, 

replace parts where necessary, and retest. Table 19 describes the equipment 

required to carry out the THOR–50M 

qualification tests, along with the 

associated setup procedures. Some of 

this equipment is the same or similar to 

the equipment required for qualification 

of ATDs currently defined in Part 572. 

For example, the THOR–50M 

qualification procedures for the neck 

and the upper thorax use the same 

equipment as used in qualification of 

the HIII–50M. For equipment not 

currently defined in Part 572, the 

necessary drawings are included in the 

THOR–50M drawing package with two 

exceptions: the impactors for the face 

qualification test and upper leg and 

knee qualification tests. We believe that 

existing impactors (such as the knee 

impact probe for the HIII–5F 178) can be 

modified or ballasted to achieve the 

required mass. 

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179National Highway Traffic Safety 

Administration (2020). THOR–50M Durability 

Report. Regulations.gov Docket ID NHTSA–2019– 

0106–0003, available at: https://

www.regulations.gov/document/NHTSA-2019-0106- 

0003. 

180Saunders, J., Parent, D., Ames, E., 2015. 

NHTSA oblique crash test results: vehicle 

performance and occupant injury risk assessment in 

vehicles with small overlap countermeasures. In: 

Proceedings of the 24th International Technical 

Conference for the Enhanced Safety of Vehicles (No. 

15–0108). Available at https://

downloads.regulations.gov/NHTSA-2019-0106- 

0008/attachment_1.pdf. 

181The increase in energy of the upper leg impact 

test was later implemented in the revised 

qualification procedure. 

TABLE 19—EQUIPMENT REQUIRED FOR QUALIFICATION TESTS

Test fixture description 

[±0.02 kg, ±0.25 mm] Reference Section(s) Title 

Rigid disk impactor 23.36 kg, 152.4 mm 

diameter disk.

CFR Title 49, § 572.36(a); DL500–325 4, 7, 8 Head, Upper Thorax, Lower Thorax. 

Rigid disk impactor 13.0 kg, 152.4 mm 

diameter disk.

THOR–50M Qualification Procedures, 

Section 5.2.

5 Face. 

Neck pendulum ...................................... Figure A–2; CFR Title 49, § 572.33(c)3 6.6, 6.7, 6.8, 6.9 Neck Torsion, Neck Frontal Flexion, 

Neck Extension, Neck Lateral Flexion. 

THOR neck twist fixture ......................... DL472–1000 .......................................... 6.6 Neck Torsion. 

Lower abdomen probe face assembly ... DL472–3000 .......................................... 9 Abdomen. 

Rigid disk impactor 12.0 kg, 76.2 mm 

diameter disk.

THOR–50M Qualification Procedures, 

Section 11.2.

11 Upper Leg, Knee. 

Dynamic impactor .................................. TLX–9000–013 ...................................... 12, 13, 14 Ankle Inversion and Eversion, Ball of 

Foot, Heel. 

External positioning bracket ................... TLX–9000–016M ................................... 12, 14 Ankle Inversion and Eversion, Heel. 

Dynamic inversion/eversion bracket ...... TLX–9000–015 ...................................... 12 Ankle Inversion and Eversion. 

Lower leg mounting bracket assembly .. DL472–4100 .......................................... 12, 13 Ankle Inversion and Eversion, Ball of 

Foot 

Lower leg zero bracket .......................... DL472–3500 .......................................... 3.4 Ankle Rotary Potentiometer Zeroing 

Procedure. 

Achilles fixture complete assembly ........ DL472–4000 .......................................... 3.5 Achilles Cable Adjustment Procedure. 

Load cell mounting assembly ................ DL472–4200 .......................................... 3.5 Achilles Cable Adjustment Procedure. 

Knee slider load distribution bracket assembly.DL472–5000 .......................................... 11 Knee. 

Tibia adaptor .......................................... DL472–4300 .......................................... 14 Heel. 

B. Durability and Maintenance 

In previous sections of the NPRM, we 

have discussed NHTSA’s biofidelity 

testing, qualification testing, and sled 

tests. In this testing, we generally 

observed that THOR–50M stood up well 

during testing and required 

maintenance consistent with existing 

Part 572 ATDs. In addition to that 

testing, NHTSA has conducted a variety 

of other tests over the last several years 

as development of THOR–50M has 

progressed. With respect to evaluating 

THOR’s durability and maintenance 

needs, three series of tests are especially 

useful because they subject the THOR– 

50M to more severe or challenging 

crashes: elevated energy qualification 

tests; OMDB testing; and unbelted 

FMVSS No. 208 tests. We discuss this 

testing in the sections that follow. 

1. Elevated Energy Qualification Test 

Series 

In order to assess THOR–50M’s 

durability, NHTSA conducted an 

additional series of qualification tests at 

elevated energy levels (for example, 

impactor velocities that exceeded the 

levels specified in the qualification test 

procedures).179 A series of five tests was 

conducted for each of the qualification 

test modes (except, as explained below, 

the abdomen). The first test in each set 

was a baseline test performed according 

to the qualification, except that if the 

response measurement did not either 

represent at least a 50% risk of injury 

or have a magnitude greater than the 

mean plus one standard deviation of the 

same measurement in a set of 18 oblique 

vehicle crash tests,180 the test speed was 

increased until either of those targets 

were met; this was then considered the 

baseline speed. There were two test 

modes where the test speed specified in 

the qualification procedures did not 

reach either of these targets: upper leg 

impact and heel impact.181 The next 

three tests were at speeds corresponding 

to energy level increases of 10 percent, 

20 percent, and 30 percent. A final 

baseline test was then performed at the 

prescribed qualification test velocity. 

The results were considered to show 

acceptable durability if the final 

baseline test demonstrated a response 

similar to the initial baseline test and 

within the qualification targets, and 

visual inspection revealed no damage to 

any of the dummy components. For a 

majority of the qualification test modes, 

durability was found to be acceptable. 

No visible damage was observed in any 

of the tested components after the series 

of five tests. Two exceptions to these 

findings occurred in the face and the 

abdomen qualification test modes. 

In the face impact test, the final 

baseline peak probe force and peak head 

CG resultant acceleration were higher 

than the qualification specifications. 

This is consistent with the results of the 

qualification R&R study (Section VI.A). 

While not ideal, we believe that, 

because this is now a known issue, it 

can be managed with the replacement of 

a face foam insert when the face 

qualification test results are higher in 

magnitude than the qualification 

specification. Moreover, the 

deterioration in the face foam insert 

probably would not meaningfully affect 

crash test results because, in a vehicle 

test, more energy will likely be absorbed 

by a vehicle interior component and/or 

restraint system compared to the rigid 

qualification impact probe. However, 

NHTSA would consider specifying a 

different face foam material or design 

that had improved durability, as long as 

the material or design does not 

introduce unintended consequences 

such as negatively impacting biofidelity, 

changes to the inertial properties of the 

head, degradation of repeatability and 

reproducibility, overall usability, or 

other concerns. 

We did not conduct elevated-energy 

tests for the abdomen because the 

qualification test already demonstrates a 

higher energy condition than a vehicle 

crash test. Accordingly, impacts at a 


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182Saunders, J., & Parent, D. (2018). Repeatability 

and reproducibility of oblique moving deformable 

barrier test procedure (No. 2018–01–1055). SAE 

Technical Paper, available at https://

www.regulations.gov/document/NHTSA-2019-0106- 

0005. The discussion here briefly summarizes some 

of the relevant results from this report. This testing 

is not being considered as an evaluation of the 

ATD’s repeatability and reproducibility because in 

order to provide a meaningful ATD R&R analysis, 

control of the test conditions must be exercised. 

Component tests, such as the qualification tests, are 

more readily controlled and thus may be expected 

to provide the best estimates of a dummy’s R&R. 

Sled testing provides an efficient alternative to 

vehicle crash testing and offers insight into the 

dummy’s performance as a complete system. In fullvehicle crash testing, however, the variation 

contributed by the vehicle (e.g., variation in 

structural materials) and the overall test procedure 

make it difficult to identify the variability 

attributable to the dummy itself. Additionally, the 

severity of the test conditions utilized for R&R 

assessment must also be considered. For example, 

if the test conditions are so severe that the 

responses are near or beyond the dummy’s 

mechanical limits or electronic capacity, then the 

corresponding R&R analysis may not be meaningful. 

See generally Rhule et al (2005). 

183Saunders, J., Parent, D., Martin, P., 2023. 

THOR–50M Fitness Assessment In FMVSS No. 208 

Unbelted Crash Tests. In: Proceedings of the 24th 

International Technical Conference for the 

Enhanced Safety of Vehicles (No. 23–0339). 

Available at: https://www-esv.nhtsa.dot.gov/ 

Proceedings/27/27ESV-000339.pdf. 

184S14.5.2; S5.1.2(b). 

185National Highway Traffic Safety 

Administration (2008). Laboratory Test Procedure 

for FMVSS 208, Occupant Crash Protection, TP208– 

14. 

186National Highway Traffic Safety 

Administration (2020). Revised THOR 50th 

Percentile Male Dummy Seating Procedure, June 

2019. Regulations.gov Docket ID NHTSA–2019– 

0106–0006, available at https://

www.regulations.gov/document/NHTSA-2019-0106- 

0006. 

higher energy level could cause damage 

due to exhausting the stroke of the 

abdomen instrumentation. Moreover, 

this would not be meaningful as it 

would represent a loading condition not 

representative of the front seat vehicle 

crash test environment. However, we do 

recognize that our testing has shown 

that damage to the abdomen deflection 

instrumentation can occur in vehicle 

crash test environments where 

submarining is possible, such as 

reclined rear seats. For example, several 

rear seat sled tests were conducted at 

VRTC in 2015 in which the IR–TRACCs 

installed in the abdomen experienced 

dislodged internal retaining rings and 

damage including pinched cables. These 

issues are believed to have resulted from 

interaction of the IR–TRACC tubes with 

the foam inserts inside of the lower 

abdomen bag. To address this, the lower 

abdomen sewing assembly (472–4763) 

was redesigned in late 2015, and an 

inspection procedure was added to the 

drawing package (472–8320) to ensure 

that the lower abdomen foam inserts 

remain aligned once installed in the 

assembled lower abdomen bag. 

We seek comment on these issues, 

especially on alternative equivalent face 

foams. 

2. Oblique OMDB Test Series 

In developing THOR–50M, NHTSA 

ran a series of full-vehicle oblique tests 

with a moving deformable test barrier 

(OMDB).182 Three crash tests were 

conducted on the same make/model 

vehicle (a 2016 Mazda CX–5) at three 

different test facilities. ATDs were 

seated in both front outboard seats and 

were fully qualified. Two THOR–50M 

ATDs were successfully implemented in 

a total of nine vehicle crash tests, with 

qualification tests before and after each 

set of three tests. In this test condition, 

there were no signs of damage beyond 

normal wear and tear, and there were no 

sensor failures that were critical to the 

calculation of injury risk. The dummies 

were inspected after each test. 

There were no signs of damage 

beyond normal wear and tear, and no 

part replacements were necessary. We 

did observe some sensor anomalies or 

failures to sensors, but almost all the 

sensors that failed were non-critical— 

for example off-axis channels (e.g., right 

femur X-axis force) or sensors not used 

in the calculation of injury criteria (e.g., 

lower neck load cell, foot 

accelerometers). See Appendix F. Such 

sensor anomalies can also occur in other 

Part 572 ATDs, such as the HIII–50M 

and HIII–05F used in Frontal NCAP 

testing. In the past six years of Frontal 

NCAP testing, there was an average of 

one failed ATD sensor channel per crash 

test (0.68 ± 1.08), with five of those 

instances occurring in a critical channel. 

Many of these anomalies were the 

results of loose Amphenol pins. These 

are the electrical contacts inside of the 

connectors used to interface the THOR– 

50M umbilical cables with the specific 

data acquisition system of the test 

facility. These connectors are used to 

prevent the need for cutting wires and 

attaching lab-specific connectors each 

time an ATD is sent to a new facility 

with a different data acquisition system. 

In practice, ATDs sent to test facilities 

for the execution of regulation or 

consumer information testing will often 

remain on-site for an extended period of 

time, which makes laboratory-specific 

connectors more feasible. Such issues 

would not exist for THOR–50M ATDs 

with in-dummy data acquisition 

systems. Many of the sensor failures that 

occurred were in non-critical 

instrumentation, for example off-axis 

channels or sensors not used in the 

calculation of injury criteria. For 

research tests, a larger number of 

sensors are recorded for the sake of 

completeness and post-test 

investigation; in a regulatory or 

consumer information testing 

environment, these channels may not be 

recorded. If the user does want to record 

such sensors, they would need to be 

repaired or replaced before pre-test 

qualification for the next vehicle crash 

test. 

The only sensor anomalies related to 

the calculation of injury criteria were in 

the chest and abdomen, but, once 

linearized, scaled, filtered, and 

converted to three-dimensional 

resultant deflection local spine 

coordinate system, these ‘‘blips’’ were 

no longer evident; thus they would not 

influence the calculation of injury risk 

for this occupant. These voltage drops 

are characteristic of the abrupt decreases 

in the IR–TRACC voltage time-history 

described in Section III.E.2. See 

Appendix F. 

3. FMVSS No. 208 Unbelted Vehicle 

Crash Tests 

NHTSA performed a series of 

unbelted vehicle crash tests required in 

FMVSS No. 208. The results are briefly 

summarized in this section and are 

discussed in more detail in the 

referenced paper.183 FMVSS No. 208 

specifies a frontal crash test into a rigid 

barrier with the barrier angle at 0 

degrees to ± 30 degrees at between 20 

mph (32 km/h) and 25 mph (40 km/h), 

inclusive, with an unbelted 50th 

percentile male dummy seated at either 

front outboard seat.184

NHTSA ran two sets of tests. First, we 

ran this test at the highest regulatory 

speed of 40 km/h (25 mph) for crash 

geometries of 30 degrees to the left, 30 

degrees to the right, and perpendicular 

(12 tests). Second, we ran a modified 

version of this test, with an elevated 

speed of 48 km/h (30 mph) for crash 

geometries of 30 degrees to the left and 

right (six tests). We tested with two 

different THOR–50M ATDs, both 

manufactured by Humanetics and built 

to the 2018 drawing package (except 

that one ATD (EG2595) was fitted with 

the proposed optional in-dummy DAS). 

For these tests, the laboratory test 

procedures for FMVSS No. 208 185 were 

followed, with the exception of the 

seating procedure, for which the 

Revised THOR 50th Percentile Male 

Dummy Seating Procedure 186 was 

followed. The ATD was instrumented so 

that all injury criteria defined for the 

HIII–50M in FMVSS No. 208 and in the 

THOR–50M Injury Criteria Report could 

be calculated. A total of 19 tests were 

run on four different vehicle models 


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187To maximize efficiency, the partial 

qualification test series only included the tests that 

did not require any disassembly of dummy 

components: head, upper thorax, lower thorax, 

lower abdomen, and left/right upper leg. The face 

impact test was not included because direct impact 

to the face was not expected during this test series. 

188Saunders, J., & Parent, D. (2018). Repeatability 

and reproducibility of oblique moving deformable 

barrier test procedure (No. 2018–01–1055). 189These results were shared with the vehicle 

manufacturer, which instituted a series of 

modifications. In a later test of the vehicle, there 

were no passenger air bag tears evident, and the 

head injury criteria were similar to those measured 

in the previous tests that did not appear to result 

in air bag tears. 190 49 U.S.C. 30182(f). 

191S. Rep. No. 89–1301, at 15, reprinted in 

U.S.C.C.A.N. 2709, 2723. 

192See, e.g., 38 FR 8455 (Apr. 2, 1973) (NPRM for 

the initial 50th percentile male dummy) (‘‘To the 

knowledge of this agency, the only patent on a 

component of the specified dummy is one on the 

knee held by Alderson, and that company has 

stated to the NHTSA that it will license production 

under its patent for a reasonable royalty.’’) 

193See, e.g., 65 FR 17180, 17187 (Mar. 31, 2000) 

(final rule for twelve-month-old child dummy) 

(declining to incorporate a copyrighted PADI 

developed by an ATD manufacturer and instead 

incorporating a NHTSA-authored PADI). 

(the Honda Accord, Mazda CX–5, 

Chevrolet Equinox, and Ford Escape). 

This study showed that the THOR– 

50M, when exercised in unbelted frontal 

rigid barrier testing, experienced only 

minor issues. We performed a full set of 

qualification tests before the test series, 

a partial qualification test series 187 after 

each test, and a full qualification test 

series halfway through the test series. In 

all cases, the THOR–50Ms met the 

qualification specifications without 

need for part replacement or other 

refurbishment. In addition, each ATD 

was inspected after each test for damage 

and to investigate sensor anomalies. 

While no parts were found to be in need 

of replacement, there were some sensor 

anomalies and damage. One of the ATDs 

did not experience any sensor 

anomalies or damage during testing, 

while the other ATD experienced some 

sensor anomalies that were repairable, 

while others were not. The sensors that 

were not repaired were non-critical 

channels (for example, the left tibia 

mid-shaft X-axis accelerometer), thus a 

decision was made to continue testing 

instead of repairing or replacing the 

sensors, which would have caused 

delays in the test schedule. The quantity 

and severity of sensor anomalies were 

similar to those experienced in testing 

with the HIII–50M, especially 

considering increased sensor count and 

level of complexity of the THOR–50M. 

Aside from minor wear and tear (e.g., 

scrapes on the top of the head skin of 

one ATD were noted after one test) there 

was no damage to either ATD and both 

met all qualification specifications. 

Based on these observations, NHTSA 

tentatively concludes that THOR–50M 

is sufficiently durable for use in FMVSS 

No. 208 unbelted testing, even at an 

elevated closing speed. Overall, this 

unbelted test series provides additional 

assurance that the THOR–50M units are 

durable and stand up well under testing, 

with the amount of wear and tear 

normal for our test dummies, and that 

NHTSA’s THOR–50M design 

specifications have resulted in highly 

uniform and durable units. 

C. Sensitivity to Restraint System 

Performance 

NHTSA’s testing with the THOR–50M 

has also highlighted its ability to detect 

differences in restraint system 

performance. One example of this 

occurred in the Oblique OMDB testing 

described above in Section VII.B.2.188

This testing involved vehicles of the 

same model and model year with a 

THOR–50M seated in each front 

outboard seat. In one series of tests 

which included three Oblique OMDB 

crash tests of the same vehicle make and 

model, the THOR–50Ms seated in the 

right front passenger seat showed a 

much wider variation in injury 

assessment values related to head injury 

risk than the THOR–50Ms seated in the 

driver’s seat. A thorough investigation 

of the test data, including inspection of 

the high-speed video, revealed that the 

right front passenger air bag did not 

function consistently to manage the 

ride-down of the occupant: the highspeed images revealed differences in air 

bag deployment, interaction between 

the head and the air bag, and contact 

between the head and the instrument 

panel. Inspection of the air bag revealed 

tears in the air bags in two of the three 

tests, with the largest tears associated 

with the highest injury assessment 

values.189 This is one example of how 

the innovative features of the THOR– 

50M can help lead to improved vehicle 

safety. 

VIII. Intellectual Property 

While there is no specific prohibition 

on specifying a patented component, 

copyrighted design, or name-brand 

product in Part 572, NHTSA has been 

mindful of the legislative history of the 

Safety Act and its own responsibility 

under statute to make all information, 

patents, and developments related to a 

research and development activity 

available to the public where it makes 

more than a minimal contribution to the 

activity.190 This understanding has 

guided dummy development at NHTSA 

for many years and explains why 

NHTSA has not incorporated into final 

rules materials owned by third parties 

except in rare cases (discussed below). 

The legislative history of the Safety Act 

shows that while Congress explicitly 

declined to include a provision 

preventing use of patents by the agency 

in standards, Congress did ‘‘assume[ ] 

that the Secretary is not likely to adopt 

a standard which can be met only by 

using a single patented device, and that 

the Secretary would, before doing so, 

take steps to obtain an understanding 

from the patent holder that he would 

supply the item or grant licenses on 

reasonable terms.’’ 191 In addition, 

NHTSA itself plays a significant role in 

the testing, evaluation and performance 

verification of dummies and provides a 

substantial amount of information to the 

public to identify the basis for 

improvement in testing devices to 

ensure the repeatability and 

reproducibility of results. The outcome 

of the agency’s involvement has been an 

interest in making sure the test device 

is available for use without restriction to 

the public. 

To be clear, there are also several 

potential concerns with specifying 

proprietary components. They may be 

modified by the proprietary source such 

that original is no longer available, and 

the new part no longer fits. The 

proprietary source may alter the part in 

ways that change the response of the 

dummy, such that dummies with the 

newer part do not provide the same 

response as dummies with the older 

part. Components produced by only one 

manufacturer are not subject to 

competitive sales pressures. And the 

manufacturer of a sole-source part may 

simply cease manufacturing the part. 

For these reasons, NHTSA has 

generally avoided specifying in Part 572 

patented components or copyrighted 

designs without either securing 

agreement from the rights-holder for the 

free use of the item or to license it on 

reasonable terms 192 or developing an 

alternative unencumbered by any rights 

claims.193

As noted earlier in the preamble 

(Section III), we are specifying some 

patented parts but not without 

specifying suitable alternates where no 

intellectual property claims apply. We 

briefly discuss these below. 

Shoulder 

As explained earlier, we are 

proposing to include two alternative 

shoulder specifications: the SD–3 

shoulder and the alternate shoulder. 

Humanetics has two patents on the 

SD–3 shoulder: one describes a 

mechanical shoulder joint assembly and 

the other describes an upper arm 


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194U.S. Patent Nos. 9,514,659 (upper arm 

assembly) and 9,799,234 (shoulder joint assembly). 

195H.R. 3684 (117th Congress) (2021). 

196 § 1.1. 

197 § 2.1. 

198 § 3.1. 

assembly with a load cell.194 The 

shoulder joint is formed using a pivot 

connected to a spring element inside of 

a housing, which has an adjustable 

element to control the friction of the 

joint. Humanetics is currently the sole 

manufacturer of the SD–3 shoulder in 

the United States. 

In order to avoid potential concerns 

with specifying a patented part as the 

sole specification, NHTSA has 

developed an alternative to the SD–3 

shoulder. The alternate shoulder does 

not include the adjustable friction 

element, and does not use a coil, clock, 

or watch spring mechanism. Instead, the 

alternate shoulder design uses a molded 

rubber cylinder acting as a torsion bar. 

The response of the rubber cylinder can 

be tuned by both changes in material 

and changes in geometry, such as 

removal of material to create voids of 

different sizes and shapes. This lack of 

a friction adjustment in the alternate 

shoulder is a change in the functional 

aspect of the design. Accordingly, with 

the significant differences noted, we are 

proposing to specify the use of either 

the alternate shoulder or the SD–3 

shoulder. 

Chest Instrumentation 

NHTSA is proposing the IR–TRACC 

and the S-Track as permissible alternate 

instrumentation. While NHTSA is not 

aware of any patent protection on the 

IR–TRACC, it is manufactured only by 

Humanetics. There is a patent on the STrack, and NHTSA’s understanding is 

that the S-Track is currently 

manufactured only by ATD-LabTech, 

which was recently acquired by 

Humanetics. 

We believe that specifying the design 

such that either the IR–TRACC or the STrack could be used would be sufficient 

to ensure instrumentation availability to 

dummy users. We seek comment on 

this. 

IX. Consideration of Alternatives 

NHTSA is not aware of a 50th 

percentile male ATD intended for use in 

frontal or frontal oblique crash tests and 

more advanced than the HIII–50M, other 

than the THOR–50M. Throughout this 

document we have discussed various 

alternative configurations, 

specifications, and tests that we have 

considered in developing the proposal 

and on which we are seeking comment. 

As discussed in more detail in the 

rulemaking analyses section, Executive 

Order 13609 provides that international 

regulatory cooperation can reduce, 

eliminate, or prevent unnecessary 

differences in regulatory requirements. 

Similarly, § 24211 of the Infrastructure, 

Investment, and Jobs Act 195 instructs 

DOT to harmonize the FMVSS with 

global regulations to the maximum 

extent practicable (for example, to the 

extent that harmonization would be 

consistent with the Safety Act). 

The only regulatory authority or 

consumer ratings program we are aware 

of that currently uses the THOR–50M is 

Euro NCAP. Euro NCAP TB026 

references the August 2018 drawing 

package,196 the September 2018 

Qualification Procedures,197 and the 

August 2018 PADI.198 Although TB026 

largely follows these documents, it does 

depart from them in several ways. Those 

differences have been identified and 

discussed in the relevant sections of the 

preamble and are summarized in Table 

20. The tentative reasons for those 

differences are explained in detail in the 

relevant section of the preamble. In 

general, we believe that those 

differences are justified given NHTSA’s 

experience testing with the THOR–50M 

in frontal rigid barrier and frontal 

oblique vehicle crash test modes, and 

the necessity of ensuring that a dummy 

specified for use in regulatory 

compliance testing be objectively 

specified. 

TABLE 20—SUMMARY OF DIFFERENCES BETWEEN THE THOR–50M AS PROPOSED AND AS SPECIFIED FOR USE IN EURO

NCAP 

Issue Proposal Euro NCAP 

Design & Construction: 

Split shoulder pad ...................................... Not proposed .................................................... Under consideration. 

Spine .......................................................... Spine Pitch Change Joint ................................. Four-Position Spine Box. 

Lower Leg ................................................... THOR-specific lower leg .................................. HIII–50M lower leg. 

Instrumentation: 

S-Track/IR–TRACC .................................... IR–TRACC or S-Track ..................................... IR–TRACC, S-Track, or KIR–TRACC 

Does not specify the systems part-by-part with 

engineering drawings. 

In-dummy DAS ........................................... Permitted as optional configuration with partby-part engineering drawings compatible 

with the SLICE6 and any other similarlyconfigured system.

TB026 requires an in-dummy DAS. TB029 

currently does not specify any specific indummy DAS, although earlier versions of 

TB029 did specify a few different approved 

in-dummy DAS systems. 

Does not specify the systems part-by-part with 

engineering drawings. 

Qualification Tests: 

Acceptance interval midpoint ..................... Based on R&R test data .................................. Basis not identified in TB026. 

Acceptance interval width .......................... ± 10% of midpoint ............................................ Varies from ±1% to ±10%. 

Upper thorax ............................................... Ratio of Z-axis to X-axis deflection not specified as test parameter.Specifies ratio of Z-axis to X-axis deflection as 

test parameter. 

Face impact test ......................................... Specified ........................................................... Not specified. 

Knee slider ................................................. Specified ........................................................... Certified to SAE J2876. 

Lower legs ......................................................... Ankle inversion/eversion; Ball of foot; heel ...... Certified to Annex 10 of ECE Regulation No. 

94. 


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199See 1 CFR 51.7(b) (‘‘The Director will assume 

that a publication produced by the same agency that 

is seeking its approval is inappropriate for 

incorporation by reference. A publication produced 

by the agency may be approved, if, in the judgment 

of the Director, it meets the requirements of 

paragraph (a) and possesses other unique or highly 

unusual qualities. A publication may be approved 

if it cannot be printed using the Federal Register/ 

Code of Federal Regulations printing system.’’); 

(a)(2)(i)(‘‘published data, criteria, standards, 

specifications, techniques, illustrations, or similar 

material’’); (a)(3)(‘‘reasonably available to and 

usable by the class of persons affected’’); 

(a)(3)(i)(‘‘The completeness and ease of handling of 

the publication’’). 

200The qualification procedures document states 

that the photographs are provided for reference 

only. 

201 49 CFR, Part 5, Subpart B; Department of 

Transportation Order 2100.6A, Rulemaking and 

Guidance Procedures, June 7, 2021. 

202FMVSS No. 208 THOR–50M Compliance 

Option (RIN 2127–AM21), Fall 2023 Unified 

Agenda of Regulatory and Deregulatory Actions; 

Department of Transportation, available at https:// 

www.reginfo.gov/public/do/eAgendaViewRule?

pubId=202304&RIN=2127-AM21. 

X. Lead Time 

Since this rulemaking action itself 

would not impose requirements on 

anyone, we are proposing that the final 

rule would be effective on publication 

in the Federal Register. 

XI. Incorporation by Reference 

Under regulations issued by the Office 

of the Federal Register (1 CFR 51.5(a)), 

an agency, as part of a final rule that 

includes material incorporated by 

reference, must summarize in the 

preamble of the final rule the material 

it incorporates by reference and discuss 

the ways the material is reasonably 

available to interested parties or how 

the agency worked to make materials 

available to interested parties. 

In this proposed rule, NHTSA 

incorporates by reference a technical 

data package for the THOR–50M. The 

technical data package consists of twodimensional engineering drawings and a 

parts list; procedures for assembly, 

disassembly, and inspection (PADI); and 

qualification procedures. Copies of 

these documents are available in the 

research docket identified earlier in this 

document. Interested persons can 

download a copy of the materials or 

view the materials online by accessing 

www.Regulations.gov. The material is 

also available for inspection at the 

Department of Transportation, Docket 

Operations, Room W12–140, 1200 New 

Jersey Avenue SE, Washington, DC 

Telephone: 202–366–9826. If the 

proposed rule is finalized, final versions 

of these documents would be placed in 

a docket that would be readily available 

to the public online (via regulations.gov) 

and in-person at DOT headquarters. 

Although agency-created documents 

are presumptively ineligible for 

incorporation by reference, they may be 

approved for incorporation by the Office 

of the Federal Register if they (among 

other things) consist of criteria, 

specifications, or illustrations; are 

reasonably available to the class of 

persons affected; are easy to handle; and 

possesses other unique or highly 

unusual qualities.199

We believe these documents (which 

were created by NHTSA) meet these 

criteria. Except for the qualification 

procedures, NHTSA typically 

incorporates these elements of the 

technical data package by reference. 

NHTSA has not typically incorporated 

the qualification procedures by 

reference. Doing so is a departure from 

the other ATDs currently specified in 

Part 572, for which the qualification 

tests are set out in full in the regulatory 

text in each of the relevant paragraphs 

(corresponding to that ATD) in part 572. 

We are proposing a separate 

qualification procedures document for 

the THOR–50M because the THOR–50M 

qualification procedures involve 

procedures that are made clearer by 

photographs and diagrams that are not 

amenable to publication in the CFR.200

We believe this extra level of detail will 

be helpful for end users who are 

attempting to qualify the ATD. We seek 

comment on this. 

XII. Regulatory Analyses 

Executive Order (E.O.) 12866, E.O. 

13563, E.O. 14094, and DOT Regulatory 

Policies and Procedures 

NHTSA has considered the impacts of 

this regulatory action under Executive 

Orders 12866, 13563, 14094, and the 

Department of Transportation’s 

regulatory policies and procedures.201

This rulemaking action was not 

reviewed by the Office of Management 

and Budget under E.O. 12866. It is also 

not considered ‘‘of special note to the 

Department’’ under DOT Order 

2100.6A. We have considered the 

qualitative costs and benefits of the 

proposed rule under the principles of 

E.O. 12866. 

This document would amend 49 CFR 

part 572 by adding design and 

performance specifications for an 

advanced test dummy representative of 

a 50th percentile adult male that the 

agency would possibly use in FMVSS 

No. 208 front crash tests and for 

research purposes. This Part 572 

proposed rule would not impose any 

requirements on anyone. Businesses are 

affected only if they choose to 

manufacture or test with the dummy. 

There are benefits associated with this 

rulemaking but they are not readily 

quantifiable. The THOR–50M is an 

advanced dummy with advantages over 

existing dummies with respect to 

biofidelity, instrumentation, injury 

prediction, and evaluation of vehicle 

performance. The dummy is currently 

used for testing by Euro NCAP, and may 

be incorporated in ECE R137. It is also 

likely being used by vehicle and 

restraint manufacturers for testing, 

research, and development. 

Accordingly, NHTSA is considering a 

proposal to incorporate the THOR–50M 

into FMVSS No. 208, ‘‘Occupant crash 

protection,’’ for use in frontal crash 

compliance testing at the manufacturers’ 

option.202 This contemplated 

rulemaking action would permit 

manufacturers to direct NHTSA to use 

the THOR–50M in belted and unbelted 

barrier crash testing of the vehicles they 

produce instead of the HIII–50M ATD in 

NHTSA’s compliance tests. 

Incorporating the dummy in Part 572 

will enable manufacturers and others to 

streamline testing, choosing to use 

THOR–50M in place of the HIII–50M, 

potentially reducing the number of tests 

they run, and leveraging the value of the 

tests they do run. 

Incorporating the THOR–50M into 

Part 572 would also have other benefits 

beyond use in NHTSA’s compliance 

testing. The ability of the THOR–50M to 

potentially monitor additional injury 

modes and its improved biofidelity may 

facilitate the development and 

introduction of innovative occupant 

crash protection features. While the 

purpose of Part 572 is to ‘‘describe the 

anthropomorphic test devices that are to 

be used for compliance testing of motor 

vehicles and motor vehicle equipment 

with motor vehicle safety standards,’’ it 

also serves as a definition of the ATD for 

other purposes as well, such as 

consumer information crash testing, 

standards and regulations in other 

transportation modes, and research. As 

such, it would be to the benefit of 

government, academia, and the multimodal transportation industry to 

include a definition of the THOR–50M 

ATD in Part 572. In addition, the 

availability of this dummy in a 

regulated format would be beneficial by 

providing a suitable, stabilized, and 

objective test tool to the safety 

community for use in better protecting 

occupants in frontal impacts. 

The costs associated with the THOR– 

50M only affect those who choose to use 

the THOR–50M. This rule would not 

impose any requirements on anyone. If 

incorporated into FMVSS No. 208, 

NHTSA would use the dummy in its 

compliance testing of the requirements 


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61946 Federal Register / Vol. 88, No. 172 / Thursday, September 7, 2023 / Proposed Rules 

at the option of a regulated entity, but 

regulated entities are not required to use 

the dummy or assess the performance of 

their products in the manner specified 

in the FMVSSs. 

NHTSA has found that the cost of a 

THOR–50M corresponding to the 2023 

drawing package has been 

approximately $550,000 to $750,000 

depending on whether an in-dummy 

DAS is installed and the level of 

instrumentation. The minimum set of 

instrumentation needed for qualification 

testing includes 66 channels. If the STrack were used instead of the IR– 

TRACC, the total cost would be roughly 

the same. 

In addition to these costs, as with any 

ATD, dummy refurbishments and part 

replacements are an inherent part of 

ATD testing. Various parts will likely 

have to be refurbished or replaced, but 

we generally do not know which parts 

are likely to be worked on the most. As 

we note in the NPRM, however, the face 

foam appears to need more frequent 

replacement but this should not add 

appreciably to the overall cost. Because 

the dummies are designed to be 

reusable, costs of the dummies and of 

parts can be amortized over a number of 

tests. While the expected maintenance 

costs for the THOR–50M are expected to 

be higher than those for less complex 

dummies such as the HIII–50M, these 

costs are expected to be similar to 

advanced dummies such as the 

WorldSID. 

There are minor costs associated with 

conducting the qualification tests. Most 

of the qualification fixtures are common 

with those used to qualify other Part 572 

dummies (including the neck pendulum 

and the probes used in the head, upper 

thorax and lower thorax tests). Some 

additional equipment unique to the 

THOR–50M may be fabricated from 

drawings within the technical data 

package, for an estimated cost of about 

$50,000. This includes the cost to 

fabricate the torsion fixture for the neck 

torsion test, the lower abdomen probe 

face assembly, impact probes not used 

for other Part 572 dummies (or weighted 

collars to achieve the specified mass), 

and test apparatus for the lower leg tests 

(including the dynamic impactor, 

external positioning bracket, dynamic 

inversion/eversion bracket, lower leg 

mounting bracket, lower leg zero 

bracket, Achilles fixture, load cell 

mounting assembly, knee slider load 

distribution bracket, and tibia adapter). 

The costs of the instrumentation 

equipment needed to perform the 

qualification tests amounts to about an 

additional $4,400 (two angular rate 

sensors, $850 apiece; two test probe 

accelerometers, $800 apiece; one rotary 

potentiometer, $1,100). 

Regulatory Flexibility Act 

Pursuant to the Regulatory Flexibility 

Act (5 U.S.C. 601 et seq., as amended by 

the Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996), whenever an agency is required 

to publish a proposed or final rule, it 

must prepare and make available for 

public comment a regulatory flexibility 

analysis that describes the effect of the 

rule on small entities (i.e., small 

businesses, small organizations, and 

small governmental jurisdictions), 

unless the head of the agency certifies 

the rule will not have a significant 

economic impact on a substantial 

number of small entities. The Small 

Business Administration’s regulations at 

13 CFR part 121 define a small business, 

in part, as a business entity ‘‘which 

operates primarily within the United 

States.’’ (13 CFR 121.105(a)). 

We have considered the effects of this 

rulemaking under the Regulatory 

Flexibility Act. I hereby certify that this 

rulemaking action would not have a 

significant economic impact on a 

substantial number of small entities. 

This action would not have a significant 

economic impact on a substantial 

number of small entities because the 

addition of the test dummy to Part 572 

would not impose any requirements on 

anyone. This NPRM only proposes to 

include the dummy in NHTSA’s 

regulation for crash test dummies; it 

does not propose NHTSA’s use of the 

ATD in agency testing or require anyone 

to manufacture the dummy or to test 

motor vehicles or motor vehicle 

equipment with it. 

National Environmental Policy Act 

NHTSA has analyzed this proposed 

rule for the purposes of the National 

Environmental Policy Act and 

determined that it would not have any 

significant impact on the quality of the 

human environment. 

Executive Order 13045 and 13132 

(Federalism) 

Executive Order 13045 (62 FR 19885, 

April 23, 1997) applies to any rule that: 

(1) is determined to be ‘‘economically 

significant’’ as defined under E.O. 

12866, and (2) concerns an 

environmental, health, or safety risk that 

NHTSA has reason to believe may have 

a disproportionate effect on children. If 

the regulatory action meets both criteria, 

we must evaluate the environmental 

health or safety effects of the planned 

rule on children and explain why the 

planned regulation is preferable to other 

potentially effective and reasonably 

feasible alternatives considered by us. 

This proposed rule is not subject to 

the Executive Order because it is not 

economically significant as defined in 

E.O. 12866. 

NHTSA has examined this proposed 

rule pursuant to Executive Order 13132 

(64 FR 43255, August 10, 1999) and 

concluded that no additional 

consultation with States, local 

governments or their representatives is 

mandated beyond the rulemaking 

process. The agency has concluded that 

the proposed rule would not have 

federalism implications because the 

proposed rule would not have 

‘‘substantial direct effects on the States, 

on the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government.’’ This proposed 

rule would not impose any 

requirements on anyone. Businesses 

will be affected only if they choose to 

manufacture or test with the dummy. 

Further, no consultation is needed to 

discuss the preemptive effect of this 

proposed rule. While NHTSA’s safety 

standards can have preemptive effect, 

the proposed rule would amend 49 CFR 

part 572 and is not a safety standard. 

This Part 572 proposed rule would not 

impose any requirements on anyone. 

Civil Justice Reform 

With respect to the review of the 

promulgation of a new regulation, 

section 3(b) of Executive Order 12988, 

‘‘Civil Justice Reform’’ (61 FR 4729, 

February 7, 1996) requires that 

Executive agencies make every 

reasonable effort to ensure that the 

regulation: (1) Clearly specifies the 

preemptive effect; (2) clearly specifies 

the effect on existing Federal law or 

regulation; (3) provides a clear legal 

standard for affected conduct, while 

promoting simplification and burden 

reduction; (4) clearly specifies the 

retroactive effect, if any; (5) adequately 

defines key terms; and (6) addresses 

other important issues affecting clarity 

and general draftsmanship under any 

guidelines issued by the Attorney 

General. This document is consistent 

with that requirement. 

Pursuant to this Order, NHTSA notes 

as follows. 

The issue of preemption is discussed 

above in connection with E.O. 13132. 

NHTSA notes further that there is no 

requirement that individuals submit a 

petition for reconsideration or pursue 

other administrative proceeding before 

they may file suit in court. 


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Paperwork Reduction Act 

Under the Paperwork Reduction Act 

of 1995, a person is not required to 

respond to a collection of information 

by a Federal agency unless the 

collection displays a valid control 

number from the Office of Management 

and Budget (OMB). This proposed rule 

would not have any requirements that 

are considered to be information 

collection requirements as defined by 

the OMB in 5 CFR part 1320. 

National Technology Transfer and 

Advancement Act 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (NTTAA), Public Law 104– 

113, section 12(d) (15 U.S.C. 272) 

directs NHTSA to use voluntary 

consensus standards in its regulatory 

activities unless doing so would be 

inconsistent with applicable law or 

otherwise impractical. Voluntary 

consensus standards are technical 

standards (e.g., materials specifications, 

test methods, sampling procedures, and 

business practices) that are developed or 

adopted by voluntary consensus 

standards bodies. The NTTAA directs 

NHTSA to provide Congress, through 

OMB, explanations when the agency 

decides not to use available and 

applicable voluntary consensus 

standards. 

The following voluntary consensus 

standards have been used in developing 

the THOR–50M: 

• SAE J211–1, Instrumentation for 

impact test—Part 1: Electronic 

Instrumentation, Version 2014–03–31 

• SAE J1733, Sign Convention for 

Vehicle Crash Testing, Version 2007– 

11–02. 

• SAE J2570, Performance 

specifications for anthropomorphic test 

device transducers, Version 2009–08– 

12. 

• SAE J2876, Low Speed Knee Slider 

Test Procedure for the Hybrid III 50th 

Male Dummy, Version 2015–05–07. 

• ISO–MME Task Force, 2015–04–15 

proposed mnemonic codes for the 

THOR–50M. 

Unfunded Mandates Reform Act 

The Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4) (UMRA) 

requires agencies to prepare a written 

assessment of the costs, benefits, and 

other effects of proposed or final rules 

that include a Federal mandate likely to 

result in the expenditures by States, 

local or tribal governments, in the 

aggregate, or by the private sector, of 

$100 million or more (adjusted annually 

for inflation with base year of 1995) in 

any one year. Adjusting this amount by 

the implicit gross domestic product 

price deflator for 2022 results in $177 

million (111.416/75.324 = 1.48). The 

assessment may be included in 

conjunction with other assessments, as 

it is here. UMRA requires the agency to 

select the ‘‘least costly, most costeffective or least burdensome alternative 

that achieves the objectives of the rule.’’ 

This proposed rule would not impose 

any unfunded mandates under the 

UMRA. This proposed rule does not 

meet the definition of a Federal mandate 

because it does not impose requirements 

on anyone. It amends 49 CFR part 572 

by adding design and performance 

specifications for a 50th percentile adult 

male frontal crash test dummy that the 

agency could use in FMVSS No. 208 

and for research purposes. This 

proposed rule would affect only those 

businesses that choose to manufacture 

or test with the dummy. It would not 

result in costs of $100 million or more 

(adjusted for inflation) to either State, 

local, or tribal governments, in the 

aggregate, or to the private sector. 

Plain Language 

Executive Order 12866 and E.O. 

13563 require each agency to write all 

rules in plain language. Application of 

the principles of plain language 

includes consideration of the following 

questions: 

• Have we organized the material to 

suit the public’s needs? 

• Are the requirements in the rule 

clearly stated? 

• Does the rule contain technical 

language or jargon that isn’t clear? 

• Would a different format (grouping 

and order of sections, use of headings, 

paragraphing) make the rule easier to 

understand? 

• Would more (but shorter) sections 

be better? 

• Could we improve clarity by adding 

tables, lists, or diagrams? 

• What else could we do to make the 

rule easier to understand? 

If you have any responses to these 

questions, please include them in your 

comments on this proposal. 

Regulation Identifier Number 

The Department of Transportation 

assigns a regulation identifier number 

(RIN) to each regulatory action listed in 

the Unified Agenda of Federal 

Regulations. The Regulatory Information 

Service Center publishes the Unified 

Agenda in April and October of each 

year. You may use the RIN contained in 

the heading at the beginning of this 

document to find this action in the 

Unified Agenda. 

Privacy Act 

In accordance with 5 U.S.C. 553(c), 

DOT solicits comments from the public 

to better inform its rulemaking process. 

DOT posts these comments, without 

edit, to www.regulations.gov, as 

described in the system of records 

notice, DOT/ALL–14 FDMS, accessible 

through www.dot.gov/privacy. In order 

to facilitate comment tracking and 

response, we encourage commenters to 

provide their name, or the name of their 

organization; however, submission of 

names is completely optional. Anyone 

is able to search the electronic form of 

all comments received into any of our 

dockets by the name of the individual 

submitting the comment (or signing the 

comment, if submitted on behalf of an 

association, business, labor union, etc.). 

You may review DOT’s complete 

Privacy Act Statement in the Federal 

Register published on April 11, 2000 

(Volume 65, Number 70; Pages 19477– 

78). 

XIII. Public Participation 

How do I prepare and submit 

comments? 

Your comments must be written and 

in English. To ensure that your 

comments are correctly filed in the 

Docket, please include the agency name 

and the docket number or Regulatory 

Identification Number (RIN) in your 

comments. 

Your comments must not be more 

than 15 pages long. (49 CFR 553.21). We 

established this limit to encourage you 

to write your primary comments in a 

concise fashion. However, you may 

attach necessary additional documents 

to your comments. There is no limit on 

the length of the attachments. 

If you are submitting comments 

electronically as a PDF (Adobe) file, 

NHTSA asks that the documents be 

submitted using the Optical Character 

Recognition (OCR) process, thus 

allowing NHTSA to search and copy 

certain portions of your submissions. 

Please note that pursuant to the Data 

Quality Act, in order for substantive 

data to be relied upon and used by the 

agency, it must meet the information 

quality standards set forth in the OMB 

and DOT Data Quality Act guidelines. 

Accordingly, we encourage you to 

consult the guidelines in preparing your 

comments. OMB’s guidelines may be 

accessed at https://

www.transportation.gov/regulations/ 

dot-information-dissemination-qualityguidelines. 


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How can I be sure that my comments 

were received? 

If you wish the Docket to notify you 

upon its receipt of your comments, 

enclose a self-addressed, stamped 

postcard in the envelope containing 

your comments. Upon receiving your 

comments, the Docket will return the 

postcard by mail. 

How do I submit confidential business 

information? 

You should submit a redacted ‘‘public 

version’’ of your comment (including 

redacted versions of any additional 

documents or attachments) to the docket 

using any of the methods identified 

under ADDRESSES. This ‘‘public version’’ 

of your comment should contain only 

the portions for which no claim of 

confidential treatment is made and from 

which those portions for which 

confidential treatment is claimed has 

been redacted. See below for further 

instructions on how to do this. 

You also need to submit a request for 

confidential treatment directly to the 

Office of Chief Counsel. Requests for 

confidential treatment are governed by 

49 CFR part 512. Your request must set 

forth the information specified in Part 

512. This includes the materials for 

which confidentiality is being requested 

(as explained in more detail below); 

supporting information, pursuant to Part 

512.8; and a certificate, pursuant to Part 

512.4(b) and Part 512, Appendix A. 

You are required to submit to the 

Office of Chief Counsel one unredacted 

‘‘confidential version’’ of the 

information for which you are seeking 

confidential treatment. Pursuant to Part 

512.6, the words ‘‘ENTIRE PAGE 

CONFIDENTIAL BUSINESS 

INFORMATION’’ or ‘‘CONFIDENTIAL 

BUSINESS INFORMATION 

CONTAINED WITHIN BRACKETS’’ (as 

applicable) must appear at the top of 

each page containing information 

claimed to be confidential. In the latter 

situation, where not all information on 

the page is claimed to be confidential, 

identify each item of information for 

which confidentiality is requested 

within brackets: ‘‘[ ].’’ 

You are also required to submit to the 

Office of Chief Counsel one redacted 

‘‘public version’’ of the information for 

which you are seeking confidential 

treatment. Pursuant to Part 512.5(a)(2), 

the redacted ‘‘public version’’ should 

include redactions of any information 

for which you are seeking confidential 

treatment (i.e., the only information that 

should be unredacted is information for 

which you are not seeking confidential 

treatment). 

NHTSA is currently treating 

electronic submission as an acceptable 

method for submitting confidential 

business information to the agency 

under Part 512. Please do not send a 

hardcopy of a request for confidential 

treatment to NHTSA’s headquarters. 

The request should be sent to Dan 

Rabinovitz in the Office of the Chief 

Counsel at Daniel.Rabinovitz@dot.gov. 

You may either submit your request via 

email or request a secure file transfer 

link. If you are submitting the request 

via email, please also email a courtesy 

copy of the request to John Piazza at 

John.Piazza@dot.gov. 

Will the agency consider late 

comments? 

We will consider all comments 

received before the close of business on 

the comment closing date indicated 

above under DATES. To the extent 

possible, we will also consider 

comments that the docket receives after 

that date. If the docket receives a 

comment too late for us to consider in 

developing a final rule (assuming that 

one is issued), we will consider that 

comment as an informal suggestion for 

future rulemaking action. 

How can I read the comments submitted 

by other people? 

You may read the comments received 

by the docket at the address given above 

under ADDRESSES. The hours of the 

docket are indicated above in the same 

location. You may also see the 

comments on the internet. To read the 

comments on the internet, go to http:// 

www.regulations.gov. Follow the online 

instructions for accessing the dockets. 

Please note that even after the 

comment closing date, we will continue 

to file relevant information in the docket 

as it becomes available. Further, some 

people may submit late comments. 

Accordingly, we recommend that you 

periodically check the Docket for new 

material. You can arrange with the 

docket to be notified when others file 

comments in the docket. See 

www.regulations.gov for more 

information. 

List of Subjects in 49 CFR Part 572 

Motor vehicle safety, Incorporation by 

reference. 

Proposed Regulatory Text 

In consideration of the foregoing, 

NHTSA proposes to amend 49 CFR part 

572 as follows: 

PART 572—ANTHROPOMORPHIC 

TEST DEVICES 

■ 1. The authority citation for part 572 

continues to read as follows: 

Authority: 49 U.S.C. 322, 30111, 30115, 

30117 and 30166; delegation of authority at 

49 CFR 1.95. 

■ 2. Add Subpart X, consisting of 

§§ 572.220 through 572.221, to read as 

follows: 

Subpart X—THOR–50M 50th Percentile Male 

Frontal Impact Test Dummy 

Secs. 

572.220 Incorporation by reference. 

572.221 General description. 

Subpart X—THOR–50M 50th Percentile 

Male Frontal Impact Test Dummy 

§ 572.220 Incorporation by reference. 

Certain material is incorporated by 

reference (IBR) into this part with the 

approval of the Director of the Federal 

Register under 5 U.S.C. 552(a) and 1 

CFR part 51. To enforce any edition 

other than that specified in this section, 

NHTSA must publish a document in the 

Federal Register and the material must 

be available to the public. This material 

is available for inspection at the 

Department of Transportation, the 

National Archives and Records 

Administration (NARA), and in 

electronic format through 

regulations.gov. Contact DOT at: 

Department of Transportation, Docket 

Operations, Room W12–140, 1200 New 

Jersey Avenue SE, Washington DC 

20590, telephone 202–366–9826. For 

information on the availability of this 

material at NARA, email fr.inspection@

nara.gov or go to www.archives.gov/ 

federal-register/cfr/ibr-locations. To 

locate the material on regulations.gov, 

search for Docket No. NHTSA–202X– 

XXXX. The material may be obtained 

from the source: 

(a) NHTSA Technical Information 

Services, 1200 New Jersey Ave. SE, 

Washington, DC 20590, telephone 202– 

366–5965. 

(1) A drawing package entitled, 

‘‘THOR–50th Percentile Male with 

Alternate Shoulders Frontal Crash Test 

Dummy (THOR–50M Male w/Alt. 

Shoulders) Drawings, External 

Dimensions, and Mass Properties,’’ 

dated (and revised) January 2023 

(Drawings and Specifications); IBR 

approved for § 572.221. 

(2) A parts list entitled, ‘‘Parts List, 

THOR–50th Percentile Male Frontal 

Crash Test Dummy with Alternate 

Shoulders (THOR–50M w/Alt. 

Shoulders)’’ dated (and revised) January 

2023 (Parts List); IBR approved for 

§ 572.221. 

(3) A procedures document entitled 

‘‘THOR 50th Percentile Male (THOR– 

50M) Procedures for Assembly, 

Disassembly, and Inspection (PADI)’’ 

dated (and revised) June 2023 (PADI); 

IBR approved for § 572.221. 


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(4) A procedures document entitled 

‘‘THOR 50th Percentile Male (THOR– 

50M) Qualification Procedures and 

Requirements’’ dated (and revised) 

April 2023 (Qualification Procedures); 

IBR approved for § 572.221. 

§ 572.221 General description. 

(a) The THOR–50M 50th percentile 

male test dummy is defined by the 

following materials: 

(1) The Drawings and Specifications 

(incorporated by reference, see 

§ 572.220); 

(2) The Parts List (incorporated by 

reference, see § 572.220); 

(3) The PADI (incorporated by 

reference, see § 572.220); 

(4) The Qualification Procedures 

(incorporated by reference, see 

§ 572.220). 

Issued under authority delegated in 49 CFR 

1.95, 501.4, and 501. 

Ann Carlson, 

Acting Administrator. 

[FR Doc. 2023–19008 Filed 9–6–23; 8:45 am] 

BILLING CODE 4910–59–P 


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