ISO/DTS 4654

Road vehicles — Advanced automatic collision notification (AACN) systems — Methodology for creating and validating algorithms for injury level prediction

This document outlines methodologies for creating and evaluating AACN algorithms, using suitable parameters, to predict the level of injury sustained by road users in a collision. The injury prediction is used to facilitate emergency response after a collision occurs. The methodology is based on onboard vehicle data and occupant-related information and applies to vehicle occupants and vulnerable road users. This document is applicable to road vehicles having provisions for measuring and communicating crash related data. This document does not provide recommendations on suitable actions how the risk information is further used. Data format for sending vehicle information and communication protocol between vehicle and the public service answering point (PSAP) is outside the scope of this document.

Véhicules routiers — Systèmes intelligents de notification automatique de collision — Méthodologie pour créer et valider les algorithmes de prédiction du niveau de blessure

General Information

• Status: Not Published
• ICS: 43.040.15 - Car informatics. On board computer systems
• Technical Committee: ISO/TC 22/SC 36 - Safety and impact testing
• Drafting Committee: ISO/TC 22/SC 36/WG 7 - Traffic accident analysis methodology
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 03-Apr-2025
• Due Date: 03-Apr-2025
• Completion Date: 03-Apr-2025

Standards Content (Sample)

FINAL DRAFT
Technical
Specification
ISO/TC 22/SC 36
Road vehicles — Advanced
Secretariat: AFNOR
automatic collision notification
Voting begins on:
(AACN) systems — Methodology for
2025-04-03
creating and validating algorithms
Voting terminates on:
for injury level prediction
2025-05-29
Véhicules routiers — Systèmes intelligents de notification
automatique de collision — Méthodologie pour créer et valider
les algorithmes de prédiction du niveau de blessure
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
Technical
Specification
ISO/TC 22/SC 36
Road vehicles — Advanced
Secretariat: AFNOR
automatic collision notification
Voting begins on:
(AACN) systems — Methodology for
creating and validating algorithms
Voting terminates on:
for injury level prediction
Véhicules routiers — Systèmes intelligents de notification
automatique de collision — Méthodologie pour créer et valider
les algorithmes de prédiction du niveau de blessure
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 AACN injury severity prediction overview . 3
5 Vehicle and road user data for injury prediction application . 5
5.1 Introduction .5
5.2 Vehicle-related input parameters .6
5.3 Vehicle occupant-related input parameters .6
5.4 Vulnerable road user data .7
6 Injury prediction algorithm development . 8
6.1 General .8
6.2 Applicability of retrospective data for AACN use .8
6.3 Modelling methods .8
6.3.1 Introduction .8
6.3.2 Example implementation of the logistic regression model for creating an injury
risk curve .9
6.3.3 Alternative modelling methods .9
6.3.4 Important considerations for selecting model parameters .10
7 Recommendations on the metrics to validate injury prediction algorithms .10
7.1 Common performance metrics used to assess classification algorithms .10
7.1.1 General .10
7.1.2 Categorising outcomes from model prediction to enable performance assessment .10
7.1.3 Confusion matrix.11
7.1.4 Derived quantities used in assessing performance .11
7.2 Interpreting performance metrics using diagnostic curves in the context of AACN
implementation . 12
7.2.1 Introduction . 12
7.2.2 Receiver Operator Curve . 12
7.2.3 Precision recall curve .14
7.2.4 Effect of class imbalance on ROC and precision recall curves . .14
7.2.5 Connection between ROC, PR curves and triage related terms . 15
7.3 Summary of recommendations on performance metrics .17
8 Recommendation for monitoring the AACN algorithm .18
8.1 Overfitting .18
8.1.1 Overfitting risk .18
8.1.2 Approach for overfitting mitigation. 20
8.2 Ensure the response of the algorithm to obvious physical variables . . 20
8.2.1 Analysis of relationships between variables and model response . 20
8.2.2 Evidence of the algorithm response to obvious physical variables . 23
9 Spatial and temporal validity .23
Annex A (informative) AACN algorithm research publications .24
Annex B (informative) Example implementation of the logistic regression model for creating
an injury risk curve .34
Annex C (informative) Detailed processes involved in assessing the performance of AACN
algorithms prior to implementation .36
Bibliography .40

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 36 Safety
and impact testing.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
This document provides guidance on advanced automatic collision notification (AACN) algorithms for
injury level prediction and related parameters. Guidance on the evaluation of such AACN algorithms is also
presented. This document does not establish a particular AACN injury level prediction algorithm or impose
a specific input data set.
This document contributes to an appropriate implementation, overall, saving lives. Different parties (as
listed below) will benefit from applying this document.
Benefits for implementors (e.g. OEMs, countries) listed below for implementor groups respectively:
— implementors currently not having an AACN algorithm: this document helps to efficiently develop and
evaluate one, facilitating more rapid introduction;
— implementors having AACN algorithm already in a region: implementors can use this document to
demonstrate appropriateness;
— implementors having an AACN algorithm and wanting to enter new market: this document helps to
ensure and demonstrate appropriateness for new market.
Benefits for
...

Version date: 2025-01-16
ISO/TC 22/SC 36/WG 7
Secretariat: SIS AFNOR
Date: 2025-03-19
Road vehicles — Advanced Automatic Collision Notificationautomatic
collision notification (AACN) systems — Methodology for creating
and validating algorithms for injury level prediction
Véhicules routiers — Systèmes intelligents de notification automatique de collision — Méthodologie pour créer
et valider les algorithmes de prédiction du niveau de blessure

DTS stage
Warning for WDs and CDs
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change
without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which
they are aware and to provide supporting documentation.

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Fax: [phone]
EmailE-mail: [e-mail]
Website: www.iso.orgwww.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 AACN injury severity prediction overview . 4
5 Vehicle and road user data for injury prediction application . 6
5.1 Introduction . 6
5.2 Vehicle-related input parameters . 7
5.3 Vehicle occupant-related input parameters . 8
5.4 Vulnerable road user data . 8
6 Injury prediction algorithm development . 9
6.1 General. 9
6.2 Applicability of retrospective data for AACN use . 9
6.3 Modelling methods . 10
7 Recommendations on the metrics to validate injury prediction algorithms . 12
7.1 Common performance metrics used to assess classification algorithms . 12
7.2 Interpreting performance metrics using diagnostic curves in the context of AACN
implementation . 14
7.3 Summary of recommendations on performance metrics . 23
8 Recommendation for monitoring the AACN algorithm . 24
8.1 Overfitting . 24
8.2 Ensure the response of the algorithm to obvious physical variables . 27
9 Spatial and temporal validity . 30
Annex A (informative) AACN algorithm research publications . 32
Annex B (informative) Example implementation of the logistic regression model for creating an
injury risk curve . 42
Annex C (informative) Detailed processes involved in assessing the performance of AACN
algorithms prior to implementation . 45
Bibliography . 53

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 36 Safety
and impact testing.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document provides guidance on advanced automatic collision notification (AACN) algorithms for injury
level prediction and related parameters. Guidance on the evaluation of such AACN algorithms is also
presented. This document does not establish a particular AACN injury level prediction algorithm or impose a
specific input data set.
This document contributes to an appropriate implementation, overall, saving lives. Different parties (as listed
below) will benefit from applying this document.
Benefits for implementors (e.g.,. OEMs, countries) listed below for implementor groups respectively:
— Implementorsimplementors currently not having an AACN algorithm: this document helps to efficiently
develop and evaluate one, facilitating more rapid introduction;
— Implementorsimplementors having AACN algorithm already in a region: implementors can use this
document to demonstrate appropriateness;
— Implementorsimplementors having an AACN algorithm and wanting to enter new market: this document
helps to ensure and demonstrate appropriateness for new market.
Benefits for first respondents, doctors and paramedics:
— Advanceadvance estimation of expected injury severities in the crash scene;
— Unifyingunifying advance estimation increases the possibility of using algorithms providing similar
estimations of injury severity;
— Reducedreduced time to start medical treatment and improved triage for injured road users involved in a
crash.
Benefits for society:
— Endend users are all road traffic participants involved in a traffic accident. In a collision, car occupants
and/or vulnerable road users can have a better chance to mitigate or survive injuries when there is an
AACN injury level prediction algorithm to facilitate rapid response by dispatching appropriate emergency
services.
v
Road vehicles — Advanced Automatic Collision Notificationautomatic
collision notification (AACN) systems — Methodology for creating and
validating algorithms for injury level prediction
1 Scope
This document outlines methodologies for creating and evaluating AACN algorithms, using suitable
parameters, to predict the level of injury sustained by road users in a collision.
The injury prediction is used to facilitate emergency response after a collision occurs.
The methodology is based on onboard vehicle data and occupant-related information and applies to vehicle
occupants and vulnerable road users.
This document is applicable to road vehicles having provisions for measuring and communicating crash
related data.
This document provides neither a particular AACN injury level prediction algorithm, nor information on how
to use the estimated probability of injury to decide on further suitable actions (rescue, medical, etc.).
Data format for sending vehicle information and communication protocol between the vehicle and the public
service answering point (PSAP) is outside the scope of this document.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1
3.1 Advanced Automatic Collision Notification
advanced automatic collision notification system
AACN system
system that carries out automatic notification of traffic accidents, providing information measured by the
vehicle aiming to predict the level of injury sustained by road users
Note 1 to entry: Additional information (not measured by the vehicle) available just after the crash (3.12could) can be
used for the prediction.
3.2 3.2
event data recorder
EDR
device or function in a vehicle that records the vehicle’s dynamic, time-series data during the time period just
prior to a crash event (e.g.,. vehicle speed vs.versus time) or during a crash event (e.g.,. Δv vs.versus time),
intended for retrieval after the crash event
Note 1 to entry: For the purposes of this definition, the event data do not include audio and video data.
Note 2 to entry: At the time of developing this document, EDR data do not include audio or video information.
[5] [6]
[SOURCE: Reference [5[SOURCE: NHTSA Part 563 and UN Regulation 160 ]
3.3], modified — Note 1 to entry was originally part of the definition, Note 2 to entry was added.]
3.3
injury risk curve
curve giving the probability, for a defined population and for a given input, to sustain a specified severity of
injury
[SOURCE: ISO/TS 18506:2014, 2.1]
3.4 3.4
retrospective traffic accident data
sets of historical traffic accident data grouped by analysis category
3.5 3.5
triage
rapid process of sorting people depending on their need for immediate medical treatment (as is usually done
in emergencies)
Note 1 to entry: See also 7.27.2 for use of triage and related definitions in the context of AACN according to this document.
[SOURCE: ISO 21243:2008, 3.30]
3.73.6 3.6
under-triage
UT
state in which a system has assessed a person as suffering from a minor injury or no injury, when the person
has suffered a severe or fatal injury
Note 1 to entry: See also 7.27.2 for use of triage (3.5) and related definitions in the context of AACN according to this
document.
3.83.7 3.7
under-triage rate
UTR
value obtained by dividing the number of severe or fatal injuries assessed as minor or no injuries by the
number of cases that actually suffered a severe or fatal injury
Note 1 to entry: See also 7.27.2 for u
...