ISO 20901:2020

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 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

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
Foreword
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This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
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iv © ISO 2020 – All rights reserved

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.
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
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
subjec
...