Intelligent transport systems -- Emergency electronic brake light systems (EEBL) -- Performance requirements and test procedures

This document contains the basic alert strategy, minimum functionality requirements, basic driver interface elements, minimum requirements for diagnostics and reaction to failure, and performance test procedures for Emergency Electronic Brake Light systems (EEBL). EEBL alerts the driver against danger caused by the emergency braking of an FV on the upcoming road, so that the driver may reduce the speed. The system does not include the means to control the vehicle to meet the desired speed. The responsibility for safe operation of the vehicle always remains with the driver. The scope of this document does not include performance requirements and test procedures of the wireless communication device used for EEBL. The requirements of communication devices are defined in other standards, e.g. the IEEE series listed in the Bibliography[6][7][8]. The test procedure in this document is designed for third party testing of the product while the test procedure can also be used for other stakeholders such as manufacturers or consumer unions. The document applies to light duty vehicles and heavy vehicles. These systems are not intended for off-road use.

Systèmes de transport intelligents -- Systèmes de diffusion de l’information d'un freinage d'urgence (EEBL) -- Exigences de performance et procédures d'essai

General Information

Status
Published
Publication Date
13-Apr-2020
Current Stage
6060 - International Standard published
Start Date
18-Mar-2020
Completion Date
14-Apr-2020
Ref Project

Buy Standard

Standard
ISO 20901:2020 - Intelligent transport systems -- Emergency electronic brake light systems (EEBL) -- Performance requirements and test procedures
English language
18 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 20901
First edition
2020-04
Intelligent transport systems —
Emergency electronic brake light
systems (EEBL) — Performance
requirements and test procedures
Systèmes de transport intelligents — Systèmes de diffusion de
l’information d'un freinage d'urgence (EEBL) — Exigences de
performance et procédures d'essai
Reference number
ISO 20901:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 20901:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 20901:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

5 Specifications and requirements......................................................................................................................................................... 3

5.1 Basic functions ........................................................................................................................................................................................ 3

5.2 Necessary functions ............................................................................................................................................................................ 4

5.3 Basic operation principle ............................................................................................................................................................... 4

5.3.1 State functional descriptions................................................................................................................................. 5

5.3.2 Operational limits ........................................................................................................................................................... 6

5.4 Alert functionality ................................................................................................................................................................................ 6

5.4.1 General...................................................................................................................................................................................... 6

5.4.2 Generating the message including emergency braking flag for broadcasting ............ 6

5.4.3 Judging to issue the alert .......................................................................................................................................... 6

5.5 Alerting element requirements ................................................................................................................................................ 7

5.5.1 EEBL-R output ................................................................................................................................................................... 7

5.5.2 Alert modality..................................................................................................................................................................... 7

5.5.3 Optional functions of EEBL-R ............................................................................................................................... 7

5.6 Performance requirement of EEBL ....................................................................................................................................... 8

5.6.1 Minimum communication range ........................................................................................................................ 8

5.6.2 System delay requirement between FV and SV ..................................................................................... 8

5.7 Driver interface requirements ................................................................................................................................................... 8

5.7.1 Alert output specification......................................................................................................................................... 8

5.7.2 Fault indication ................................................................................................................................................................. 8

6 Performance evaluation test methods ........................................................................................................................................... 8

6.1 Environmental conditions for test ......................................................................................................................................... 8

6.2 Test course conditions ...................................................................................................................................................................... 9

6.3 Test system installation and configuration .................................................................................................................... 9

6.4 Parameters recoverable from data record ...................................................................................................................... 9

6.5 Test cases ..................................................................................................................................................................................................... 9

6.6 Test procedure ......................................................................................................................................................................................10

6.6.1 Test case 1 — FV transmission test and delay measurement ................................................10

6.6.2 Test case 2 — False positive test .....................................................................................................................12

6.6.3 Test case 3 — True positive test ......................................................................................................................13

6.6.4 Test case 4 — Test when there is interfering vehicle (IV) .........................................................14

6.6.5 Test case 5 — Basic communication function test ..........................................................................16

Bibliography .............................................................................................................................................................................................................................18

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 20901:2020(E)
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 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 204, Intelligent transport systems.

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 © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 20901:2020(E)
Introduction

Emergency Electronic Brake Light systems (EEBL) alert the driver against the danger caused by the

emergency braking of a forward vehicle (FV) on the upcoming road. EEBL generates an emergency

brake message based on vehicle emergency brake and transmit. The system periodically broadcasts

the message to nearby vehicles through vehicle to vehicle (V2V) wireless communication. If the

system equipped on an FV detects the emergency braking of its own vehicle, the system generates the

emergency braking flag, and sends the message including emergency braking flag. When the system

equipped on the subject vehicle (SV) receives the message containing the emergency braking flag,

the system judges whether an alert needs to be issued. If the location of the FV is within the specified

region of interest (ROI) of the SV, the system provides an alert to the driver to prompt appropriate

deceleration for driver safety. The scope of EEBL does not include automated intervention features or

means for controlling the vehicle to match a desired speed.

A significant benefit of cooperative safety systems such as EEBL is the significant reduction of the

potential risk of collision when a driver cannot see the brake light of an FV that is braking hard. For

example, when there is an interfering vehicle between the emergency braking vehicle (FV) and the SV,

the driver in the SV can still be alerted through vehicle to vehicle (V2V) wireless communication while

on-board sensor-based systems cannot even detect the existence of the FV.
© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 20901:2020(E)
Intelligent transport systems — Emergency electronic
brake light systems (EEBL) — Performance requirements
and test procedures
1 Scope

This document contains the basic alert strategy, minimum functionality requirements, basic driver

interface elements, minimum requirements for diagnostics and reaction to failure, and performance

test procedures for Emergency Electronic Brake Light systems (EEBL).

EEBL alerts the driver against danger caused by the emergency braking of an FV on the upcoming

road, so that the driver may reduce the speed. The system does not include the means to control the

vehicle to meet the desired speed. The responsibility for safe operation of the vehicle always remains

with the driver.

The scope of this document does not include performance requirements and test procedures of the

wireless communication device used for EEBL. The requirements of communication devices are defined

[6][7][8]

in other standards, e.g. the IEEE series listed in the Bibliography . The test procedure in this

document is designed for third party testing of the product while the test procedure can also be used

for other stakeholders such as manufacturers or consumer unions.

The document applies to light duty vehicles and heavy vehicles. These systems are not intended for off-

road use.
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:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
Emergency Electronic Brake Light system
EEBL
system consisting of EEBL-T (3.1.1) and EEBL-R (3.1.2)
3.1.1
Emergency Electronic Brake Light – Transmitting system
EEBL-T

system capable of detecting the emergency braking of the vehicle where the system is equipped, and

capable of transmitting a message including emergency brake flag and other information, e.g. location,

speed, to nearby vehicles
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 20901:2020(E)
3.1.2
Emergency Electronic Brake Light – Receiving system
EEBL-R

system capable of receiving a message including emergency brake flag from forward vehicles (FVs) (3.3),

and capable of alerting the driver of emergency braking of an FV on the same road and traveling in the

same direction as the SV (3.2)
3.2
subject vehicle
receiving vehicle
vehicle equipped with the EEBL-R (3.1.2) system

Note 1 to entry: The subject vehicle is located behind and traveling in the same direction as the forward vehicle

(FV) (3.3).
3.3
forward vehicle
transmitting vehicle
vehicle equipped with the EEBL-T (3.1.1) system

Note 1 to entry: The forward vehicle (FV) (3.3) is located ahead of the subject vehicle (SV) (3.2) within the region of

interest (ROI) (3.9) of the SV.
3.4
interfering vehicle

vehicle which is located in between the subject vehicle (SV) (3.2) and forward vehicle (FV) (3.3) to

interfere with the line-of-sight between the SV and FV

Note 1 to entry: During the test, the IV does not generate a message including emergency brake flag nor issue an

emergency brake alert to the driver, so the IV will not influence the EEBL (3.1) operation of the FV (3.3) and SV.

3.5
subject vehicle speed
longitudinal component of the subject vehicle (SV) (3.2) velocity
3.6
visibility

distance at which the illuminance of a non-diffusive beam of white light with the colour temperature of

2700K is decreased to 5 % of its original light source illuminance
3.7
host lane
lane in which the subject vehicle (SV) (3.2) is located
3.8
adjacent lane

lane of travel sharing one lane boundary with the host lane and having the same direction of travel as

the host lane
3.9
region of interest
ROI

area in which a subject vehicle (SV) (3.2) receives the emergency brake flag from the forward vehicle

(FV) (3.3)
2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 20901:2020(E)
4 Symbols and abbreviated terms
a The deceleration of the FV
a Absolute value of the deceleration of the FV
d_Current
a Threshold amount of deceleration of the FV to judge the emergency braking
d_Threshold
EEBL Emergency Electronic Brake Light system
EEBL-T Emergency Electronic Brake Light -Transmitting system
EEBL-R Emergency Electronic Brake Light - Receiving system
FSRA Full Speed Range ACC
FV Forward Vehicle
FVCWS Forward Vehicle Collision Warning System
GNSS Global Navigation Satellite System
HMI Human Machine Interface
IV Interfering Vehicle
PER Packet Error Rate
ROI Region of Interest
RSE Road Side Equipment
SV Subject Vehicle
V A pre-set speed of vehicle for test
V2I Vehicle to Infrastructure communication
V2V Vehicle to Vehicle communication
V Maximum operational speed value
max
5 Specifications and requirements
5.1 Basic functions

The purpose of the EEBL is to provide alerts that will assist drivers in avoiding or reducing the severity

of rear end crashes caused by emergency braking of an FV.
EEBL has following functions.

— EEBL-T detects and judges the emergency braking of an FV, and broadcasts a message including

the emergency braking flag. For better understanding, the vehicle that broadcasts the emergency

braking flag is denoted as FV in this document.

— EEBL-R receives the message including the emergency braking flag, judges whether the alert shall

be issued, and provides the alert to the driver. For better understanding, the vehicle whose driver is

alerted is denoted as SV in this document.

— The EEBL requires both of these functions, EEBL-T and EEBL-R, on separate vehicles. The

implementations can be different for different manufacturers on their respective vehicles.

© ISO 2020 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 20901:2020(E)

The alert should be issued as soon as the SV receives the emergency braking message flag from an FV

within its ROI and has evaluated it to be relevant. EEBL provides an alert only and does not perform

vehicle control to mitigate the crash.

EEBL may suppress or delay the alert when the SV is applying an automatic braking or alert(s)

commanded by another system in the vehicle, e.g. FVCWS or FSRA.

The basic components of EEBL can include radio communication transmitter/receiver and antenna,

GNSS receiver and antenna, processing device and HMI device. The processing device can be a separate

control unit or it can be combined with another control unit.
5.2 Necessary functions

Vehicles equipped with EEBL-T shall be equipped to fulfil the following functions:

— monitor vehicle deceleration, vehicle position, vehicle speed and vehicle heading direction;

— detect emergency braking in accordance with deceleration threshold value;
— broadcast the message including emergency braking flag to nearby vehicles.

Vehicles equipped with EEBL-R shall be equipped to fulfil the following functions:

— receive the message including emergency braking flag;
— judge the position and heading of the FV with respect to the SV;

— provide alerts to driver in accordance with the EEBL function and requirements.

5.3 Basic operation principle
Figure 1 — EEBL states and transitions
4 © ISO 2020 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 20901:2020(E)
5.3.1 State functional descriptions
5.3.1.1 State transition conditions
Conditions for EEBL transitions from system Off state to system On state:

a) For EEBL vehicles equipped with on/off control, both the vehicle ignition and the on/off control are

on.

b) For EEBL vehicles not equipped with on/off control, the vehicle ignition is on.

c) The transition from EEBL Off to EEBL On may be performed by the driver or automatically.

d) The transition from EEBL Off to EEBL On shall only occur if no EEBL system failures have been

detected.
Conditions for EEBL transitions from system On state to system Off state:

a) For EEBL vehicles equipped with on/off control, either the vehicle ignition or the on/off control

are off.

b) For EEBL vehicles not equipped with on/off control, the vehicle ignition is off.

c) If the system is in on state, and a system failure occurs.

The system may be fitted with an on/off control that can be operated by the driver at all times.

EEBL shall as a minimum, provide the following operations and state transitions. The following

constitutes the fundamental behaviour of EEBL. The alert criteria are described in 5.4.

— The EEBL-T system of an FV generates the message including the emergency braking flag as long as

the vehicle braking exceeds the threshold value ( a ), and returns back to the stand-by

d_Threshold

state after the vehicle braking no longer exceeds the threshold value. The system broadcasts the

message including the emergency braking flag to nearby vehicles through V2V wireless

communication within 100 ms of detecting the emergency brake.

— When the EEBL-R system of an SV is in the stand-by state, the system monitors messages from

external wireless communication sources. If a message including the emergency braking flag is

received, the system judges the alert criteria to determine whether the alert should be issued. If

the system judges to alert, the system transitions to the alert state, and the EEBL-R starts alert(s)

immediately.

— When the EEBL-R system of an SV is in the alert state, the system provides alert(s) to the driver for

a minimum 2 s, and maximum of the duration that the FV emergency braking flag is received, and

then returns back to the stand-by state.
One of several stages or phases of system operation.

— EEBL off state: The state that EEBL is off. This state has one of the following three causes: the driver

has selected the off condition, the ignition is off, or the EEBL is in failure. The failure of EEBL means

that the system cannot function as it is described in the user manual due to the failure of the system

or the failure of the sub-component of the EEBL. The cause of failure can be, e.g. system malfunction,

communication fail, failure during self- diagnosis process.

— EEBL system on state: For EEBL-T equipped on a FV, this state is either stand-by or broadcast state.

For EEBL-R equipped on an SV, this state is either stand-by or alert state. Vehicles equipped with

EEBL-T periodically broadcast and the vehicles equipped with the EEBL-R receive status messages.

— EEBL system stand-by state: For EEBL-T equipped on a FV, the system monitors the vehicle

deceleration. For EEBL-R equipped on an SV, the system is ready to receive the message including

the emergency braking flag.
© ISO 2020 – All rights reserved 5
---------------------- Page: 10 ----------------------
ISO 20901:2020(E)

— EEBL-T transmission of emergency braking state: The system generates the emergency braking

flag, and sends the message including emergency braking flag to nearby vehicles using wireless

communication module. The EEBL-T starts broadcasting the message including emergency braking

flag if the amount of deceleration of the vehicle exceeds the threshold value.

— EEBL-R alert state: The system starts alert(s) or is operating the alert(s). The EEBL-R starts alert(s)

if the message including emergency brake flag is received, and the system judged that the alert

criteria are all met.
5.3.2 Operational limits

The maximum operational speed value (for SV) of Vmax shall be greater than or equal to 27,8 m/s.

The system shall not operate when the speed of SV or FV is less than 2,8 m/s.

The operational limits of EEBL shall be indicated in an owner’s manual and/or caution label.

5.4 Alert functionality
5.4.1 General

EEBL shall provide an alert for emergency braking of an FV in the forward path of the SV. The EEBL

alert is provided in accordance with the following functions.
5.4.2 Generating the message including emergency braking flag for broadcasting

EEBL-T monitors the deceleration of the vehicle. If the deceleration, a is greater than or equal

d_Current

to the absolute value of the threshold value, the EEBL-T generates the message including emergency

braking flag. The message is broadcast through the wireless communication module of EEBL-T to

nearby vehicles. The threshold value, a , is 4,0 m/s .
d_Threshold
If aa≥ , FV broadcasts the message including emergency braking flag.
d_Current d_Threshold
5.4.3 Judging to issue the alert

When the EEBL-R in an SV receives the message including emergency braking flag, and the FV is within

the ROI, the EEBL-R starts the alert. The judgement whether the location of the FV is inside of the ROI of

the SV’s EEBL-R is based on the GNSS location of the SV and FV.
Dimensions in metres
Figure 2 — Minimum region of interest (ROI) for EEBL

The minimum area of the ROI is described in Figure 2. The ROI in the longitudinal direction shall be

greater than or equal to 150 m measured from the tip of the front bumper of the SV. The ROI in the

lateral direction shall be greater than or equal to 6 m to both left and right sides, measured from the

center of the SV
6 © ISO 2020 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 20901:2020(E)
Longitudinal distance of ROI ≥ 150 m
Lateral distance of ROI ≥ 6 m (each left and right)
If the following criteria are all met, the alert shall be issued.
— The location of the FV is inside of the ROI of the SV.
— Both the FV and SV are traveling in the same direction on the same roadway.

— The EEBL-R is in System On state, and the gear selection is in forward or neutral position (all gear

positions except reverse and park).

It is permitted to have a larger ROI but the minimum value in both longitudinal and lateral directions

shall be at least 150 m and 12 m, respectively. If the road is curved, the longitudinal distance is measured

along the centerline of the road.

The method to judge whether the FV is in the location to cause a possible danger to SV depends upon

the manufacturer of EEBL-R.

If the manufacturer of EEBL-R can judge that the emergency brake of FV in ROI will not result in danger

for the SV (e.g. FV in adjacent lane), the EEBL-R is allowed not to provide an alert to the driver.

5.5 Alerting element requirements
5.5.1 EEBL-R output

When the alert criteria mentioned in 5.4.3 are all met, EEBL-R of the SV shall provide an emergency

brake alert to the driver.
5.5.2 Alert modality

When the system transitions to the EEBL-R alert state, the driver shall be alerted by an audible, haptic

or visual element.

While the alert is designed and provided, the following related standards may be used for reference.

— ISO/TR 12204:2012
— ISO/TS 16951:2004

Drivers shall be informed of the conditions that result in EEBL-R activation and deactivation and of the

limitations of the system performance by the vehicle owner’s manual.

If EEBL-R is not available due to a failure, the driver shall be informed, and the description of the notice

shall be stated in the vehicle owner’s manual.

An alert should be selected such that it can easily be distinguished from warnings unrelated to forward

direction threats (e.g. lateral threat warnings).
5.5.3 Optional functions of EEBL-R

The required deceleration threshold for collision may be adapted based on the detected road condition,

environmental conditions, driver conditions or driver behaviour.
The system may suppress additional alerts to avoid repetitive alerts.
The system may suppress alerts when the driver is applying the brake.

The EEBL-R alert may be suppressed or delayed if the SV is detected to be performing a lane change or

high dynamic manoeuvring.
© ISO 2020 – All rights reserved 7
---------------------- Page: 12 ----------------------
ISO 20901:2020(E)

The EEBL-R alert may be suppressed or delayed if an automatic warning braking or braking is already

activated. The automatic warning braking or braking can be issued by ACC, FVCMS or other automatic

braking systems.

It is optional to use V2I communication for EEBL-R. For example, the message including emergency

braking flag of the FV can be transferred to an RSE on road infrastructure and redirected to the SV.

If any of these optional functions is included, it shall be described in the vehicle owner’s manual.

5.6 Performance requirement of EEBL
5.6.1 Minimum communication range
The minimum communication range between the FV and SV shall be 300 m of roadway.
5.6.2 System delay requirement between FV and SV

Within the communication range required in 5.6.1, the SV shall be able to receive the message including

emergency braking flag within 0,3 s for test cases specified in 6.6. This system delay is from the time

that the EEBL-T of the FV starts generating emergency braking flag to the time that the EEBL-R of the

SV starts the alert.
Figure 3 — Definition of system delay
5.7 Driver interface requirements
5.7.1 Alert output specification

All visual, audible, and haptic alerts shall be perceptible by the driver. It is recommended that the visual

and audible alert satisfy appropriate human factors. The alert modality requirements for collision

alerts are shown in 5.5.2.
5.7.2 Fault indication

If the EEBL is in fault condition, fault indication shall be provided to driver. The indication modality can

be visual.
6 Performance evaluation test methods
6.1 Environmental conditions for test
a) The test location shall be on a flat
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.