ISO 18682:2016

Intelligent transport systems - External hazard detection and notification systems - Basic requirements

ISO 18682:2016 specifies basic requirements for systems to execute notifications such as warning and awareness messages to provide hazard information to a driver. Requirements include principle of notifying, timing of notification, distance of notification, and information elements that should be included in messages. NOTE 1 Methods of implementing functions such as hazardous conditions detection, communication, and presentation to drivers are not specified in this document. NOTE 2 The formulae in Clause 5 and calculated concrete time or distance duration in Annex A are not normative elements but informative elements.

Systèmes intelligents de transport — Détection du danger externe et systèmes de notification — Exigences de base

General Information

• Status: Published
• Publication Date: 04-Oct-2016
• ICS: 03.220.01 - Transport in general
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ISO/TC 204 - Intelligent transport systems
• Drafting Committee: ISO/TC 204/WG 14 - Vehicle/roadway warning and control systems
• Current Stage: 9060 - Close of review
• Completion Date: 04-Jun-2027

Overview

ISO 18682:2016 - Intelligent transport systems - External hazard detection and notification systems - Basic requirements defines the foundational requirements for systems that notify drivers about external hazards. The standard covers what information hazard notifications should contain, the principles of notifying, the timing and distance considerations for messages, and required message elements. It specifies high-level, system-agnostic requirements - not the specific detection, communication or presentation technologies - and includes informative (non‑normative) formulae and case examples to aid design.

Key topics and technical requirements

• Categories of notification
  • Warnings: immediate alerts that expect an immediate corrective action.
  • Awareness messages: alerts to prepare a driver for a potential hazard in the near future.
• System types
  • Autonomous (on‑board sensing only)
  • Cooperative (using infrastructure or other vehicles): I‑V (infrastructure‑vehicle) and V‑V (vehicle‑vehicle)
• Functional blocks
  • Detection (hazard sensing)
  • Assessment (hazard evaluation / decision)
  • Human‑Machine Interface (HMI) (presentation to driver)
  • Communication (for cooperative systems)
• Notification content
  • Detection information, assessment information, and the notification payload (what the driver needs to know)
• Timing and distance
  • Requirements and guidance on when notifications should be issued (time‑to‑hazard) and recommended notification distances; Annex A provides informative case studies and worked examples
• Nonfunctional requirements
  • Consistency, priority management, security, quality, and integration considerations to ensure predictable, safe behavior and interoperability
• Important notes
  • Implementation methods (sensor types, message transports, UI modalities) are intentionally not specified.
  • Formulae in Clause 5 and numerical examples in Annex A are informative, not normative.

Applications

ISO 18682:2016 is applicable to a wide range of intelligent transport and vehicle safety systems, including:

• Collision hazard warning and slow‑vehicle alerts
• Lane change assistance and blind‑spot warnings
• Red‑light and intersection crossing warnings
• Vehicle OEM and supplier development of driver alerts and ADAS features
• ITS infrastructure planners deploying roadside hazard broadcasts

Who should use this standard

• Automotive OEMs and Tier‑1 suppliers designing ADAS and driver notification systems
• HMI designers and human factors engineers responsible for in‑vehicle alerts
• ITS architects and roadway agencies implementing cooperative I‑V / V‑V services
• Regulators and certification bodies referencing basic safety notification requirements

Related standards

ISO 18682:2016 is part of the ISO/TC 204 Intelligent Transport Systems family and is intended to complement other ITS and vehicle safety standards (vehicle‑to‑vehicle (V2V), vehicle‑to‑infrastructure (V2I), HMI, and ADAS standards) when specifying how hazard information is conveyed to drivers.

Standards Content (Sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 18682
ISO/TC 204 Secretariat: ANSI
Voting begins on: Voting terminates on:
2015-09-01 2015-12-01
Intelligent transport systems — External hazard detection
and notification systems — Basic requirements
Titre manque
ICS: 03.220.01; 35.240.60
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 18682:2015(E)
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. ISO 2015

ISO/DIS 18682:2015(E)
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

ISO/DIS 18682
Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 External hazard detection and notification systems . 2
4.1 General . 2
4.2 Categories of hazard notification . 2
4.3 Types of external hazard detection and notification system . 2
4.4 Functional configuration . 3
4.4.1 Basis of functional configuration . 3
4.4.2 Detection functional block. 4
4.4.3 Assessment functional block . 4
4.4.4 Human machine interface (HMI) functional block . 5
4.4.5 Communication functional block . 5
4.5 Time factors of hazard notification . 5
4.5.1 General . 5
4.5.2 Detection functional block time factor . 6
4.5.3 Assessment functional block time factor . 6
4.5.4 HMI functional block time factor . 6
4.5.5 Communication functional block time factor . 6
4.5.6 Time factor after hazard notification . 7
5 Requirements for external hazard detection and notification systems . 7
5.1 Principle . 7
5.2 Particulars . 7
5.2.1 General . 7
5.2.2 Detection information . 7
5.2.3 Assessment information . 8
5.2.4 Notification information . 9
5.2.5 Timing of hazard notification . 9
5.2.6 Distance of hazard notification . 12
6 Nonfunctional requirements . 15
6.1 General . 15
6.2 Consistency . 15
6.3 Priority . 15
6.4 Security . 15
6.5 Quality. 15
6.6 Integration . 16
Annex A (informative) Consideration of timing and distance of hazard notification (Case study) . 17
A.1 General . 17
A.2 Support for preventing collisions with forward obstacles [I-V Cooperative type] . 17
A.3 Support for preventing lateral collisions [V-V Cooperative type] . 18
Bibliography . 20

ISO/CD 18682
iv © ISO 2014 – All rights reserved

ISO/DIS 18682
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18682 was prepared by Technical Committee ISO/TC 204, Intelligent transport systems, Working group
WG14, Vehicle/roadway warning and control systems.
ISO/CD 18682
Introduction
External hazard detection and notification systems recognize vehicle conditions and their ambient
environment using on-board remote sensing or cooperatively through communication between infrastructure
and vehicle (I-V), or among vehicles (V-V), and warn or inform the driver about external hazards.
This international standard addresses a number of functions, such as slow vehicle indication, collision hazard
warning, lane change assistance, red light warning, and intersection crossing assistance. There are common
requirements for several external hazard detection and notification systems. Many other working groups of
ISO and other standard development organizations may consider systems that assist driving safety. The
scope of ISO/TC204/WG14 is to promote a positive experience of vehicle/roadway warning and control
systems for the driver.
This international standard is not intended to provide requirements for particular systems defined in each
individual standard, but basic requirements based on basic principles for external hazard detection and
notification systems. They are common requirements in similar systems such as safety systems on nomadic
devices and systems developed in ISO/TC204/WG14, and should become root or primal requirements to
define each system’s requirements. This international standard will be referred to when designing various
systems in the future. It is expected to ensure uniformity and efficiency, and building systems that reduce the
likelihood of confusion for the driver.
For a better understanding of basic requirements, examples of typical formulas are shown in this standard as
informative elements. In addition, calculated examples of some services are given as information in the annex.
Fruitful information on particular consideration is listed in Bibliography.
vi © ISO 2014 – All rights reserved

WORKING DRAFT ISO/CD 18682
Intelligent transport systems—External hazard detection and
notification systems—Basic requirements
1 Scope
This international standard specifies basic requirements for systems to execute notifications such as warning
and awareness messages to provide hazard information to a driver.
Requirements include principle of notifying, timing of notification, distance of notification, and information
elements that should be included in messages.
NOTE Methods of implementing functions such as hazardous conditions detection, communication, and presentation
to drivers are not specified in this document.
NOTE Formulas in Section 5 and calculated concrete time or distance duration in Annex A are not normative
elements but informative elements.
2 Normative references
The following referenced documents are indispensable when applying this document. For dated references,
only the edition cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
(TBD) ISO ab-c:199x, General title of series of parts—Part c: Title of part
(TBD) ISO xyz (all parts), General title of the series of parts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
hazard notification
information that is provided to a driver to notify of external hazards
3.2
warning
one type of hazard notification that requests action be taken immediately to avoid an external hazard
3.3
awareness message
one type of hazard notification that informs the driver about an external potential hazard within a short time in
the future
3.4
hazardous condition
external conditions that have intrinsic risks of causing accidents or collisions
3.5
safe state
vehicle state that is achieved after avoiding a hazardous condition
ISO/CD 18682
4 External hazard detection and notification systems
4.1 General
External hazard detection and notification systems distinguish hazardous conditions that occur currently,
imminently, or potentially, and notify the driver with a warning and/or awareness message to adjust steering
and speed quickly enough to avoid such situations.
4.2 Categories of hazard notification
Hazard notifications given to a driver are classified into two categories according to response of the driver
expected by the system as follows:
a) Warnings
Systems detect immediate hazardous conditions, assess need to perform an avoidance manoeuvre by
the driver in a short time, and notify the driver with a warning. The driver is expected to respond
accordingly with a corrective manoeuver in a short time;
b) Awareness messages
Systems detect potentially hazardous conditions and assess that a probability of a hazard is high if the
condition remains and the driver needs to perform avoidance action. The system then notifies the driver
with an awareness message. The driver is expected to prepare to avoid a potential hazard within a short
time in the future.
4.3 Types of external hazard detection and notification system
External hazard detection and notification systems collect information on a detected hazardous condition from
various sources and assess its hazardous nature, then inform drivers via a hazard notification.
External hazard detection and notification systems are classified into two types according to how the
information is acquired:
a) autonomous external hazard detection and notification systems (Autonomous type)
Autonomous external hazard detection and notification systems assess the situation using information
obtained solely on-board the subject vehicle and notify the driver of hazards;
b) Cooperative external hazard detection and notification systems (Cooperative type)
Cooperative external hazard detection and notification systems assess the situation using information
obtained from external systems such as infrastructure or other vehicles via wireless communication and
notify the driver of hazards.
NOTE Cooperative external hazard detection and notification systems may also use information from the subject
vehicle such as velocity of vehicle and location of vehicle.
Cooperative type includes two types of system:
1) Infrastructure—vehicle cooperative external hazard detection and notification systems (I-V
Cooperative type)
Infrastructure—vehicle cooperative external hazard detection and notification systems assess a
situation using information from the subject vehicle and infrastructure, and notify the driver of
hazards;
2) Vehicle—vehicle cooperative external hazard detection and notification systems (V-V Cooperative
type)
2 © ISO 2014 – All rights reserved

ISO/DIS 18682
Vehicle—vehicle cooperative external hazard detection and notification systems assess a situation
using information from the subject vehicle and other vehicles, and notify the driver of hazards.
NOTE There may be systems that use information from both infrastructure and other vehicles.
Types of external hazard detection and notification system are shown in Table 1.
Table 1 — Types of external hazard detection and notification system that function as sources of
information
A B
Direct source of information Own vehicle Infrastructure External
B
Type vehicle
a) Autonomous type X
b) Cooperative 1) I-V Cooperative type X X
type 2) V-V Cooperative type X X
A
Information on subject vehicle such as speed, acceleration/deceleration, and location may be used regardless of system type.
B
There may be cooperative systems that use information from both infrastructure and other vehicles.

4.4 Functional configuration
4.4.1 Basis of functional configuration
Systems described in the present standard include necessary functional blocks, which encompasses:
a) Detection functional block;
b) Assessment functional block;
c) Human machine interface (HMI) functional block.
NOTE Where each function is allocated depends on system design. For example, the HMI notifies a driver of the
same notification that may be assessed by devices in infrastructures or assessed in own vehicle. There are systems in
which assessments or decisions are performed by infrastructure systems and an example of a system is described in
Annex A2.
When hazardous conditions are detected by systems outside the vehicle and transmitted to the vehicle via
wireless communication, the following function is added:
d) Communication functional blocks.
NOTE Transmitting information between devices at the same location (e.g. between vehicle devices or between
devices in the infrastructure) is not included in this functional block, but in other Detection, Assessment, or HMI functional
block.
Abstract functional block configuration is shown in Figure 1.

Figure 1 — Abstract functional block configuration
ISO/CD 18682
NOTE Where to allocate the function of the Communication functional block depends on system design.
Examples of function allocation are shown in Table 2.
Table 2 — Example of function allocation
A A A
Infrastructure Other vehicle Subject vehicle
Autonomous
- - a)detection functional
type
block
b)assessment functional
block
c)HMI functional block
I-V Cooperative
a)detection functional - d)communication
type
block functional block (I-V)
d)communication b)assessment functional
functional block (I-V) block
c)HMI functional block
V-V Cooperative
- a)detection functional block d)communication
type
functional block (V-V)
d)communication functional
B
block (V-V) b)assessment functional
block
c)HMI functional block
A
This function allocation is just an example. Each function may be allocated at other locations.
B
Relay communication via infrastructure (V-I to I-V) may be included.

4.4.2 Detection functional block
The Detection functional block detects hazardous conditions using sensors or accumulated data, and provides
them to the Assessment block. Hazardous conditions are not distinguished using only a simple measurement
value but together with time course, other measurement values, and also other information. The Detection
functional block may be located in the subject vehicle, infrastructure, or other vehicles.
NOTE Allocations of detection or related functions depend on system design.
Detection block includes the following:
 Detection function.
NOTE There may be multiple different detection functions in the vehicle and/or infrastructure.
4.4.3 Assessment functional block
The Assessment functional block handles information provided by the Detection functional block and derives
assessments needed to issue hazard notifications and provides information to the HMI functional block.
NOTE Allocation of functions for assessment or related functions depend on system design.
The Assessment functional block includes sub-functions such as the following:
 Situation assessment function
Situation assessment function assesses hazardous situations using various detected information
provided by the detection function;
EXAMPLE To assess if a vehicle will experience a rear-end collision or not
4 © ISO 2014 – All rights reserved

ISO/DIS 18682
 Notification assessment function Situation assessment function
Notification assessment function assesses implementation and content of hazard notifications
based on hazard situation assessed function.
EXAMPLE To assess which notification is suitable "apply brake" or "keep distance"
4.4.4 Human machine interface (HMI) functional block
The HMI functional block issues hazard notifications to a driver using information provided by the Assessment
functional block.
NOTE There may be two types of device that have HMI; one is designed exclusively for specific hazard notification;
the other is used in common for multiple types of hazard notification or other information provision.
The HMI functional block includes sub-functions such as the following:
 Provision processing function
Provision processing function prepares information provided to a driver. In case multiple
information is notified to the driver, the priority of each piece of information is assessed and
hazard notification is provided appropriately;
 Presentation function
Presentation function renders hazard notification to the driver.
4.4.5 Communication functional block
The Communication functional block transmits information to vehicles from the infrastructure or other vehicles
via wireless communication.
The Communication functional block includes the following functions:
 Communication function.
4.5 Time factors of hazard notification
4.5.1 General
Time factors needed from the point when a hazardous condition occurs or is detected to the point when the
vehicle has avoided a hazard are shown in Table 3.
Table 3 — Time factor
Items Time factors
Functions of Detection block
Detection function Detection time
external hazard
Assessment
Situation assessment Situation assessment time
detection and
block
function
Notification assessment time
notification
Notification assessment
systems
function
HMI block
Provision processing Provision processing time
function presentation time
Presentation function
Communication
Communication function Communication time
block
Out of function of
Time factor after hazard notification Driver reaction time
external hazard
Vehicle state variation time, until
detection and
vehicle has reached a safe state
notification
ISO/CD 18682
systems
Each function may include a certain processing time. The time required to distribute information between
devices should be included in the processing time of each function. Alternatively, the length of time may be
zero depending on the layout of functions.
4.5.2 Detection functional block time factor
The Detection functional block time factor is the time required to detect hazardous conditions. Detecting
hazardous conditions may require measurement value of time course other measurement values, and/or other
information. These are included in the detection functional block time factor.
The Detection functional block time factor includes the following time:
 Detection time.
EXAMPLE If the area or length of impediment is expanding, or the impediment is moving, the measurement value
after an interval also to detect hazardous conditions.
4.5.3 Assessment functional block time factor
The Assessment functional block time factor is the time required to assess the situation and issue a hazard
notification.
The Assessment functional block time factor includes the following times:
 Situation assessment time
The Situation assessment time is the time required to assess a situation based on detection
information;
 Notification assessment time
The Notification assessment time is the time required to assess the function and the content of a
hazard notification based on situation assessment. It assesses whether a notification is needed
or not, which notification is suitable, a warning or awareness message, etc.
NOTE In "situation assessment time", the situation is recognized, then whether a driver needs a notification and what
kind of notification is suitable are determined in "notification assessment time".
4.5.4 HMI functional block time factor
The HMI functional block time is the delay time from receiving a notification to its presentation to the driver.
The HMI functional block time factor includes the following times:
 Processing time to prepare information
The Processing time to prepare information is the time needed to prepare information to notify
the driver of a hazard notification reflected in judgment of priority;
 Presentation time
The Presentation time is the time needed to render a hazard notification to the driver.
4.5.5 Communication functional block time factor
The Communication functional block time factor is the time needed to transmit and process messages to a
vehicle from outside the vehicle (e.g. from infrastructure or other vehicles).
The Communication functional block time factor includes the following time:
6 © ISO 2014 – All rights reserved

ISO/DIS 18682
 Communication time.
4.5.6 Time factor after hazard notification
In the situation after the driver acknowledges a hazard notification, the driver responds and performs a vehicle
controlling manoeuvre. Then the vehicle can begin to avoid a hazard situation.
Time factor after hazard notification includes the following times:
 Driver reaction time
The driver reacti
...

INTERNATIONAL ISO
STANDARD 18682
First edition
2016-10-15
Intelligent transport systems —
External hazard detection and
notification systems — Basic
requirements
Systèmes intelligents de transport — Détection du danger externe et
systèmes de notification — Exigences de base
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 External hazard detection and notification systems. 2
4.1 General . 2
4.2 Categories of hazard notification . 2
4.3 Types of external hazard detection and notification system . 2
4.4 Functional configuration . 3
4.4.1 Basis of functional configuration . 3
4.4.2 Detection functional block. 4
4.4.3 Assessment functional block . 4
4.4.4 Human machine interface (HMI) functional block . 4
4.4.5 Communication functional block . 5
4.5 Time factors of hazard notification . 5
4.5.1 General. 5
4.5.2 Detection functional block time factor . 5
4.5.3 Assessment functional block time factor . 5
4.5.4 HMI functional block time factor . 6
4.5.5 Communication functional block time factor . 6
4.5.6 Time factor after hazard notification . 6
5 Requirements for external hazard detection and notification systems .7
5.1 Principle . 7
5.2 Particulars . 7
5.2.1 General. 7
5.2.2 Detection information . 7
5.2.3 Assessment information . 8
5.2.4 Notification information . 8
5.2.5 Timing of hazard notification . 9
5.2.6 Distance of hazard notification.11
6 Non-functional requirements .14
6.1 General .14
6.2 Consistency .14
6.3 Priority .14
6.4 Security .15
6.5 Quality .15
6.6 Integration .15
Annex A (informative) Consideration of timing and distance of hazard notification (case study) .16
Bibliography .19
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 204, Intelligent transport systems.
iv © ISO 2016 – All rights reserved

Introduction
External hazard detection and notification systems recognize vehicle conditions and their ambient
environment using on-board remote sensing or cooperatively through communication between
infrastructure and vehicle (I-V), or among vehicles (V-V), and warn or inform the driver about external
hazards.
This document addresses a number of functions, such as slow vehicle indication, collision hazard warning,
lane change assistance, red light warning, and intersection crossing assistance. There are common
requirements for several external hazard detection and notification systems. Many other standard
development organizations may consider systems that assist driving safety. The scope of ISO/TC 204 is
to promote a positive experience of vehicle/roadway warning and control systems for the driver.
This document is not intended to provide requirements for particular systems defined in each
individual standard, but basic requirements based on basic principles for external hazard detection
and notification systems. They are common requirements in similar systems, such as safety systems on
nomadic devices and systems developed in ISO/TC 204, and should become root or primal requirements
to define each system’s requirements. This document will be referred to when designing various
systems in the future. It is expected to ensure uniformity and efficiency and building systems that
reduce the likelihood of confusion for the driver.
For a better understanding of basic requirements, examples of typical formulae are shown in this
document as informative elements. In addition, calculated examples of some services are given as
information in the annex. Fruitful information on particular consideration is listed in the Bibliography.
INTERNATIONAL STANDARD ISO 18682:2016(E)
Intelligent transport systems — External hazard detection
and notification systems — Basic requirements
1 Scope
This document specifies basic requirements for systems to execute notifications such as warning and
awareness messages to provide hazard information to a driver.
Requirements include principle of notifying, timing of notification, distance of notification, and
information elements that should be included in messages.
NOTE 1 Methods of implementing functions such as hazardous conditions detection, communication, and
presentation to drivers are not specified in this document.
NOTE 2 The formulae in Clause 5 and calculated concrete time or distance duration in Annex A are not
normative elements but informative elements.
2 Normative references
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:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
hazard notification
information that is provided to a driver to notify of external hazards
3.2
warning
type of hazard notification (3.1) that requests action be taken immediately to avoid an external hazard
3.3
awareness message
type of hazard notification (3.1) that informs the driver about an external potential hazard within a
short time in the future
3.4
hazardous condition
external conditions that have intrinsic risks of causing accidents or collisions
3.5
safe state
vehicle state that is achieved after avoiding a hazardous condition (3.4)
4 External hazard detection and notification systems
4.1 General
External hazard detection and notification systems distinguish hazardous conditions that occur
currently, imminently, or potentially and notify the driver with a warning and/or awareness message
to adjust steering and speed quickly enough to avoid such situations.
4.2 Categories of hazard notification
Hazard notifications given to a driver are classified into two categories according to response of the
driver expected by the system as follows.
a) Warnings. Systems detect immediate hazardous conditions, assess need to perform an avoidance
manoeuvre by the driver in a short time, and notify the driver with a warning. The driver is
expected to respond accordingly with a corrective manoeuvre in a short time;
b) Awareness messages. Systems detect potentially hazardous conditions and assess that a probability
of a hazard is high if the condition remains and the driver needs to perform avoidance action. The
system then notifies the driver with an awareness message. The driver is expected to prepare to
avoid a potential hazard within a short time in the future.
4.3 Types of external hazard detection and notification system
External hazard detection and notification systems collect information on a detected hazardous
condition from various sources and assess its hazardous nature, then inform drivers via a hazard
notification.
External hazard detection and notification systems are classified into two types according to how the
information is acquired.
a) Autonomous external hazard detection and notification systems (autonomous type). Autonomous
external hazard detection and notification systems assess the situation using information obtained
solely on-board the subject vehicle and notify the driver of hazards;
b) Cooperative external hazard detection and notification systems (cooperative type). Cooperative
external hazard detection and notification systems assess the situation using information obtained
from external systems such as infrastructure or other vehicles via wireless communication and
notify the driver of hazards.
NOTE 1 Cooperative external hazard detection and notification systems may also use information from
the subject vehicle, such as velocity of vehicle and location of vehicle.
Cooperative type includes two types of systems.
1) Infrastructure-vehicle cooperative external hazard detection and notification systems
(I-V cooperative type). Infrastructure-vehicle cooperative external hazard detection and
notification systems assess a situation using information from the subject vehicle and
infrastructure and notify the driver of hazards;
2) Vehicle-vehicle cooperative external hazard detection and notification systems (V-V
cooperative type). Vehicle-vehicle cooperative external hazard detection and notification
systems assess a situation using information from the subject vehicle and other vehicles and
notify the driver of hazards.
NOTE 2 There may be systems that use information from both infrastructure and other vehicles.
Types of external hazard detection and notification system are shown in Table 1.
2 © ISO 2016 – All rights reserved

Table 1 — Types of external hazard detection and notification system that function as sources
of information
a
Direct source of information External
b
Own vehicle Infrastructure
b
Type vehicle
a)  Autonomous type X
b)  Cooperative type 1)  I-V cooperative type X X
2)  V-V cooperative type X X
a
Information on subject vehicle such as speed, acceleration/deceleration, and location may be used regardless of
system type.
b
There may be cooperative systems that use information from both infrastructure and other vehicles.
4.4 Functional configuration
4.4.1 Basis of functional configuration
Systems described in the present standard include necessary functional blocks, which encompasses the
following:
a) detection functional block;
b) assessment functional block;
c) human machine interface (HMI) functional block.
NOTE 1 Where each function is allocated depends on system design. For example, the HMI notifies a driver of
the same notification that may be assessed by devices in infrastructures or assessed in own vehicle. There are
systems in which assessments or decisions are performed by infrastructure systems and an example of a system
is described in A.2.
When hazardous conditions are detected by systems outside the vehicle and transmitted to the vehicle
via wireless communication, communication functional blocks is added.
NOTE 2 Transmitting information between devices at the same location (e.g. between vehicle devices or
between devices in the infrastructure) is not included in this functional block, but in other detection, assessment,
or HMI functional block.
Abstract functional block configuration is shown in Figure 1.
NOTE Where to allocate the function of the communication functional block depends on system design.
Figure 1 — Abstract functional block configuration
Examples of function allocation are shown in Table 2.
Table 2 — Example of function allocation
a a a
Infrastructure Other vehicle Subject vehicle
Autonomous type a)  detection functional block
— — b)  assessment functional block
c)  HMI functional block
I-V cooperative type a)  detection functional d)  communication functional
block block (I-V)
—
d)  communication b)  assessment functional block
functional block (I-V) c)  HMI functional block
V-V cooperative type a)  detection functional d)  communication functional
block block (V-V)
—
d)  communication b)  assessment functional block
b
functional block (V-V) c)  HMI functional block
a
This function allocation is just an example. Each function may be allocated at other locations.
b
Relaying communication via infrastructure (V-I to I-V) may be included.
4.4.2 Detection functional block
The detection functional block detects hazardous conditions using sensors or accumulated data and
provides them to the assessment block. Hazardous conditions are not distinguished using only a
simple measurement value but together with time course, other measurement values, and also other
information. The detection functional block may be located in the subject vehicle, infrastructure, or
other vehicles.
NOTE 1 Allocations of detection or related functions depend on system design.
Detection block includes detection function.
NOTE 2 There may be multiple different detection functions in the vehicle and/or infrastructure.
4.4.3 Assessment functional block
The assessment functional block handles information provided by the detection functional block
and derives assessments needed to issue hazard notifications and provides information to the HMI
functional block.
NOTE Allocation of functions for assessment or related functions depends on system design.
The assessment functional block includes sub-functions such as the following.
— Situation assessment function. Situation assessment function assesses hazardous situations using
various detected information provided by the detection function.
EXAMPLE 1 To assess if a vehicle will experience a rear-end collision or not.
— Notification assessment function. Notification assessment function assesses implementation and
content of hazard notifications based on hazard situation assessed function.
EXAMPLE 2 To assess which notification is suitable “apply brake” or “keep distance”.
4.4.4 Human machine interface (HMI) functional block
The HMI functional block issues hazard notifications to a driver using information provided by the
Assessment functional block.
NOTE There may be two types of device that have HMI: one is designed exclusively for specific hazard
notification; the other is used in common for multiple types of hazard notification or other information provision.
4 © ISO 2016 – All rights reserved

The HMI functional block includes sub-functions such as the following.
— Provision processing function. Provision processing function prepares information provided to a
driver. In case multiple information is notified to the driver, the priority of each piece of information
is assessed and hazard notification is provided appropriately.
— Presentation function. Presentation function renders hazard notification to the driver.
4.4.5 Communication functional block
The communication functional block transmits information to vehicles from the infrastructure or other
vehicles via wireless communication.
The communication functional block includes communication function.
4.5 Time factors of hazard notification
4.5.1 General
Time factors needed from the point when a hazardous condition occurs or is detected to the point when
the vehicle has avoided a hazard are shown in Table 3.
Table 3 — Time factor
Items Time factors
Functions of external Detection block Detection function Detection time
hazard detection and
Assessment block Situation assessment Situation assessment time
notification systems
function Notification assessment time
Notification assessment
function
HMI block Provision processing Provision processing time
function presentation time
Presentation function
Communication Communication function Communication time
block
Out of function of Time factor after hazard notification Driver reaction time
external hazard Vehicle state variation time, until
detection and vehicle has reached a safe state
notification systems
Each function may include a certain processing time. The time required to distribute information
between devices should be included in the processing time of each function. Alternatively, the length of
time may be zero depending on the layout of functions.
4.5.2 Detection functional block time factor
The detection functional block time factor is the time required to detect hazardous conditions.
Detecting hazardous conditions may require measurement value of time course, other measurement
values, and/or other information. These are included in the detection functional block time factor.
The detection functional block time factor includes detection time.
EXAMPLE If the area or length of the hazardous condition is expanding or moving, the hazardous conditions
should be detected after a regular interval.
4.5.3 Assessment functional block time factor
The assessment functional block time factor is the time required to assess the situation and issue a
hazard notification.
The assessment functional block time factor includes the following times.
— Situation assessment time. Situation assessment time is the time required to assess a situation
based on detection information.
— Notification assessment time. Notification assessment time is the time required to assess the
function and the content of a hazard notification based on situation assessment. It assesses whether
a notification is needed or not, which notification is suitable, a warning or awareness message, etc.
NOTE In “situation assessment time”, the situation is recognized, then whether a driver needs a notification
and what kind of notification is suitable are determined in “notification assessment time”.
4.5.4 HMI functional block time factor
The HMI functional block time is the delay time from receiving a notification to its presentation to
the driver.
The HMI functional block time factor includes the following times.
— Processing time to prepare information. The Processing time to prepare information is the time
needed to prepare information to notif
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