ISO 26684:2015

INTERNATIONAL ISO
STANDARD 26684
First edition
2015-05-01
Intelligent transport systems (ITS) —
Cooperative intersection signal
information and violation warning
systems (CIWS) — Performance
requirements and test procedures
Systèmes intelligents de transport (ITS) — Systèmes d’avertissement
d’information et de violation du signal d’intersection coopérative
(CIWS) — Exigences de performance et modes opératoires d’essai
Reference number
ISO 26684:2015(E)
©
ISO 2015

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ISO 26684:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2015 – All rights reserved

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ISO 26684:2015(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Classification . 3
5.1 System configuration . 3
5.2 System configuration . 3
6 Functional requirements . 4
6.1 CIWS state diagram . 4
6.1.1 CIWS states . 5
6.2 Transition criteria . 5
6.2.1 Criterion (1): RSE activation . 5
6.2.2 Criterion (2): RSE deactivation . 6
6.2.3 Criterion (3): OBE activation . 6
6.2.4 Criterion (4): OBE deactivation . 6
6.2.5 Class II criterion (5): Warning activation . 6
6.2.6 Class II criterion (6): Warning deactivation . 6
6.3 Functional requirements of OBE . 6
6.3.1 Acquisition of travel direction . 6
6.3.2 Acquisition of vehicle position . 6
6.3.3 Acquisition of vehicle speed. 6
6.3.4 Identification of traffic signal information . 6
6.3.5 Judgement of warning necessity and warning contents (Class II) . . 6
6.3.6 Timing of warning output . 7
6.3.7 Timing of warning termination . 7
6.3.8 HMI display contents. 7
6.4 Functional requirements of RSE . 7
6.4.1 Data sets . 7
6.4.2 Communication range . 7
6.4.3 Communication delay . 7
6.5 CIWS system performance . 7
6.5.1 System capabilities . . 7
6.5.2 Provision of information . 8
6.5.3 Warning threshold for signal violation . 8
7 Test requirements . 9
7.1 Test vehicle . 9
7.2 Test site . 9
7.2.1 Environmental conditions . 9
7.2.2 Geometric conditions .10
7.2.3 RSE location for the systems providing communication only at X .10
AL
7.3 Test procedure .10
7.3.1 Test method .10
Bibliography .12
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ISO 26684:2015(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/TC 204, Intelligent transport systems.
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ISO 26684:2015(E)

Introduction
The main system function of cooperative intersection signal information and violation warning
systems (CIWS) is to warn drivers who are about to violate an intersection’s traffic signal to stop at the
prescribed location. The CIWS is intended to provide a cooperative vehicle and infrastructure system
that reduces the likelihood and severity of crashes at signalized intersections by providing the signal
phase information and/or by warning the driver that an intersection signal violation is about to occur.
The system uses information communicated from the roadside infrastructure to determine if a warning
should be given to a driver.
The purpose of implementing CIWS is to reduce violations of traffic signals at signalized intersections to:
(a) reduce fatalities, (b) reduce the number and/or severity of injuries, and (c) reduce property damage
associated with collisions.
This International Standard addresses CIWS for use in road vehicles approaching signalized intersections.
This International Standard may be used as a system level standard by other standards, which extend
the CIWS to a more detailed standard utilizing wireless communication technologies. Issues such as the
specific requirements for the function and performance of communication technology or traffic control
facilities (including traffic signal controllers) will not be considered in this International Standard.
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INTERNATIONAL STANDARD ISO 26684:2015(E)
Intelligent transport systems (ITS) — Cooperative
intersection signal information and violation warning
systems (CIWS) — Performance requirements and test
procedures
1 Scope
This International Standard specifies the concept of operation, system requirements, and test methods
for cooperative intersection signal information and violation warning systems (CIWS) at signalized
intersections. CIWS are intended to reduce the likelihood of crash injury, damage, and fatality by
enhancing the capability of drivers to avoid crash situations at signalized intersections.
The scope of CIWS standardization includes basic functions, functional requirements, performance
requirements, information contents, and test methods.
The characteristics of the technologies used to communicate between the signal controller and
the vehicles are not addressed by this International Standard nor are the behavioural responses by
drivers, the various capabilities of vehicles on the road, or the multitude of combinations of these two
characteristics.
2 Normative references
There are no normative references cited in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
stopping distance
distance, X travelled by a vehicle with the speed of v, from the time the driver receives CIWS warning
v,
until the vehicle comes to a complete stop
Note 1 to entry: This includes the distance travelled during the driver perception and reaction time.
3.2
speed of vehicle
speed of the subject vehicle, v
3.3
time to arrive at stop line of intersection
TTAI
time needed for a vehicle approaching the intersection at a speed of v to travel the distance, X, from its
current location to the stop line
X
TTAI=
v
3.4
traffic signal phase
green, yellow, and red intervals within a cycle that are assigned to an independent traffic movement or
combination of movements
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ISO 26684:2015(E)

3.5
stop line
pavement marking line extending across approach lanes to indicate the point at which a stop is intended
or required to be made
3.6
road side equipment
RSE
roadside device that can supply traffic signal information to the approaching subject vehicle and may
also support determination of vehicle position and heading
3.7
onboard equipment
OBE
in-vehicle equipment that can provide drivers with information and/or warnings based on the
information received from the RSE and the vehicle
3.8
spot communication media
wireless communication system between roadside and vehicles that operates only within such a small
zone that the availability of the communication link can serve as a definitive indicator of the vehicle’s
location in support of the intended application
4 Symbols
2
d deceleration rate of subject vehicle for stopping on level pavement (m/s ), assumed for the
purpose of designing CIWS (could be specific for the vehicle type, weather conditions, and
road gradient)
G duration of green time (s)
G remaining green time (s)
r
t total time of information delay (s)
D
t the time between when the OBE receives information from the RSE and when it displays a
OBE
warning
t = t + t
OBE OBE1 OBE2
where t includes communication delay and judgement processing in OBE and t is
OBE1 OBE2
display delay to driver.
t driver’s perception-reaction time (PRT)
PRT
t the time between when the RSE receives signal status information and when it broadcasts
RSE
that information
v approach speed (m/s)
V maximum speed of vehicle, assumed for the purpose of designing CIWS (m/s)
Design
X travel distance from the current position of the vehicle to the stop line (m)
X location of downloading information from RSE (m)
AL
2
v
Design
Xv≥⋅t +
AL Design D
2⋅d
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ISO 26684:2015(E)

NOTE: Location of the RSE is limited by the physical conditions of the road. If the RSE is
2
located upstream than v t + v /(2 · d), it can communicate the information in the
Design · D Design
timing required for warning.
t = t + t
D PRT OBE
X stopping distance (m)
v
2
v
   Xv=⋅t +
v PRT
2⋅d
Y duration of yellow time (s)
5 Classification
5.1 System configuration
The system configuration should be in accordance with Figure 1.
Vehicle
interface
Vehicle
information
(optional)
Infrastructure
Display
information
information
Roadside
On board
Driver
equipment
equipment
interface
(RSE)
(OBE)
Figure 1 — System configuration
5.2 System configuration
In order to reduce the likelihood of crash injury, damage, and fatality by enhancing the capability
...