ISO 21734-1:2022

Intelligent transport systems — Performance testing for connectivity and safety functions of automated driving buses in public transport — Part 1: General framework

This document specifies the general framework and the automated driving bus (ADB) system components for operating ADBs in public transport networks, including: a) the general framework and the operation scheme for public transport systems in cooperation with ADBs; b) definitions of system components for operating ADBs; and c) definitions of functions and requirements of each system component for providing transport services with ADBs. This document is applicable to bodies in public transport systems and services including transportation operators, public transport governing authorities and relevant industries.

Systèmes de transport intelligents — Essais de performance pour les fonctions de connectivité et de sécurité des bus à conduite automatisée dans les transports publics — Partie 1: Cadre général

General Information

• Status: Published
• Publication Date: 06-Nov-2022
• ICS: 03.220.20 - Road transport
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ISO/TC 204 - Intelligent transport systems
• Drafting Committee: ISO/TC 204/WG 8 - Public transport/emergency
• Current Stage: 6060 - International Standard published
• Start Date: 07-Nov-2022
• Due Date: 23-May-2022
• Completion Date: 07-Nov-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21734-1
First edition
2022-11
Intelligent transport systems —
Performance testing for connectivity
and safety functions of automated
driving buses in public transport —
Part 1:
General framework
Systèmes de transport intelligents - Essais de performance pour
les fonctions de connectivité et de sécurité des bus à conduite
automatisée dans les transports publics —
Partie 1: Cadre général
Reference number
ISO 21734-1:2022(E)
© ISO 2022
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ISO 21734-1:2022(E)
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© ISO 2022

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ISO 21734-1:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

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

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

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

3.1 Terms and definitions ...................................................................................................................................................................... 1

3.2 Abbreviated terms .............................................................................................................................................................................. 5

4 General information ......................................................................................................................................................................................... 5

4.1 ISO 21734 series overview and structure ...................................................................................................................... 5

4.2 Purpose of the ISO 21734 series ............................................................................................................................................. 6

5 ADB system Components ............................................................................................................................................................................ 6

5.1 Overview ...................................................................................................................................................................................................... 6

5.2 ADB component ..................................................................................................................................................................................... 6

5.3 MC centre component ....................................................................................................................................................................... 7

5.4 IoT infrastructure component .................................................................................................................................................. 7

5.5 Smart bus station component ................................................................................................................................................... 7

5.6 ADB user component ......................................................................................................................................................................... 7

6 ADB system framework ................................................................................................................................................................................ 8

6.1 Overview ...................................................................................................................................................................................................... 8

6.2 Safety aspect of ADB system framework ........................................................................................................................ 8

6.2.1 General ........................................................................................................................................................................................ 8

6.2.2 Road infrastructure ........................................................................................................................................................ 8

6.2.3 Safety performance test elements of the ADB operation ............................................................... 9

6.3 Connectivity aspect of the ADB system framework .......................................................................................... 10

6.3.1 General ..................................................................................................................................................................................... 10

6.3.2 Connectivity infrastructure .................................................................................................................................. 10

6.3.3 Connectivity performance test elements of ADB operation ..................................................... 11

6.4 ADB system framework requirements ..........................................................................................................................12

6.4.1 ADB component requirements............................................................................................................................12

6.4.2 MC centre component requirements ............................................................................................................. 13

6.4.3 IoT infrastructure requirements ...................................................................................................................... 16

6.4.4 Smart bus station requirements ....................................................................................................................... 16

6.4.5 ADB user requirements ............................................................................................................................................. 17

6.5 ADB service framework .............................................................................................................................................................. 18

7 Required data sets ..........................................................................................................................................................................................19

7.1 General ........................................................................................................................................................................................................ 19

7.2 Operation .................................................................................................................................................................................................. 20

7.2.1 Signalized intersection case ................................... ............................................................................................... 20

7.2.2 Crosswalk case .................................................................................................................................................................. 21

7.2.3 Bus stop case....................................................................................................................................................................... 22

7.3 ADB service ............................................................................................................................................................................................ 23

8 Use cases ....................................................................................................................................................................................................................25

8.1 General ........................................................................................................................................................................................................ 25

8.2 Left turn on intersection ............................................................................................................................................................25

8.2.1 Use case 1-1: Protected left turn on intersection ............................................................................... 25

8.2.2 Use case 1-2: Permitted left turn on intersection .............................................................................. 26

8.3 Straight forward on intersection ........................................................................................................................................ 27

8.3.1 Use case 2: Straight forward on intersection......................................................................................... 27

8.4 Right turn on intersection ........................................................................................................................................... ..............28

8.4.1 Use case 3-1: Right turn on intersection ....................................................................................................28

8.4.2 Use case 3-2: Right turn on red on intersection ..................................................................................29

iii
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ISO 21734-1:2022(E)

8.5 Crosswalk ................................................................................................................................................................................................. 30

8.5.1 Use case 4-1: Signalized pedestrian crosswalk ...................................................................................30

8.5.2 Use case 4-2: Non-signalized pedestrian crosswalk ....................................................................... 31

8.6 Smart bus station .............................................................................................................................................................................. 32

8.6.1 Use case 5-1: Bus station with bay .................................................................................................................. 32

8.6.2 Use case 5-2: Bus station without bay .......................................................................................................... 33

Bibliography .............................................................................................................................................................................................................................35

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ISO 21734-1:2022(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.

A list of all parts in the ISO 21734 series can be found on the ISO website.

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.
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ISO 21734-1:2022(E)
Introduction

Automated vehicle technology has been developing rapidly in recent years as one of the measures for

reducing automobile accidents caused by human errors and for promoting the automobile industry.

The automated driving bus (ADB) is a new type of public transport mode embedded with automated

vehicle technologies. The progress of the development and deployment of the ADB has been accelerated

in recent years, exceeding the speed of automated passenger vehicles.

The overall purpose of this document is to provide technical standards at the international level to

ensure the safety and connectivity of the ADB operating as a public transport mode. The objectives of

this document include building a framework for operating ADBs in public transit networks, developing

performance test methods and procedures in terms of safety and connectivity of ADBs that require

communication with roadside infrastructure and with the monitoring and control centre, and providing

the service framework and use cases as references for field applications.

From the connectivity perspective, the ADB needs to be connected with traffic signal networks for

vehicles and pedestrians, with the monitoring and control centre for bus operation, and with other

relevant infrastructure to ensure its effectiveness as a public transport mode. In terms of safety, the

ADB needs to be embedded with automated vehicle functions to connect with the wireless signal

control system and to be ready to respond to unexpected situations involving other road users such as

pedestrians and bicyclists.

Furthermore, the authorities of public transport need technical standards to measure the performance

of ADB for enhancing public safety on roads.

Therefore, this document is intended to benefit public transport operators, relevant governing

authorities of public transport, and industrial stakeholders.

This document provides the basis for the development of performance testing for connectivity and

safety functions of ADB on a national and international level.
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INTERNATIONAL STANDARD ISO 21734-1:2022(E)
Intelligent transport systems — Performance testing for
connectivity and safety functions of automated driving
buses in public transport —
Part 1:
General framework
1 Scope

This document specifies the general framework and the automated driving bus (ADB) system

components for operating ADBs in public transport networks, including:

a) the general framework and the operation scheme for public transport systems in cooperation with

ADBs;
b) definitions of system components for operating ADBs; and

c) definitions of functions and requirements of each system component for providing transport

services with ADBs.

This document is applicable to bodies in public transport systems and services including transportation

operators, public transport governing authorities and relevant industries.
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 terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms and definitions
3.1.1
automated driving bus
ADB

bus designed for public transport and embedded with automated driving functions based on SAE level

4 or higher
3.1.2
operation safety

set of minimum safety requirements ensuring an automated driving bus's expected functions as a

public transport mode when operating in cooperation with road infrastructure

Note 1 to entry: Road infrastructure includes exclusive bus lanes, bus stations, signalized and non-signalized

intersections, crosswalks for pedestrians and bicyclists, general traffic signals, bus priority signals, and

monitoring and control centres.
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ISO 21734-1:2022(E)
3.1.3
safety function

set of minimum functions related to the safety of an automated driving bus (ADB) as a public transport

mode, facilitating passengers on board, at bus stations and responding to emergency events that can

arise both inside and outside of ADBs
3.1.4
connectivity of ADB

connectivity performance of an automated driving bus (ADB) system that ensures the stable and

reliable provision of the information feed required to provide safe public transport services

3.1.5
transport information

set of information required for automated driving buses (ADBs) to function as a public mode

Note 1 to entry: This includes operation information exchanged between road infrastructure and ADBs

themselves, bus priority signal information, passengers’ boarding and alighting information, roadside signage

equipment information, battery charge and discharge information (if the bus is an electric bus), etc.

3.1.6
ADB system framework

framework for ensuring stability and safety of automated driving bus system operations through

interactions among automated driving bus (ADB) system components
3.1.7
ADB system components
required components for operating an automated driving bus (ADB) system

Note 1 to entry: The components include the ADB, the monitoring and control centre, Internet of Things

infrastructure, smart bus stations and users.
3.1.8
ADB service framework

framework for transport services provided by the automated driving bus (ADB) system through

interactions among the ADB service components, consisting of the ADB, the monitoring and control

centre, passengers, smart bus stations and Internet of Things infrastructure
3.1.9
monitoring and control centre
MC centre

system that ensures the safe operation of the automated driving bus (ADB) system by monitoring

and controlling the fleet through collecting data from each component (the ADB, ADB users, Internet

of Things infrastructure, smart bus stations), processing the data, and providing comprehensive

information to each component
3.1.10
IoT infrastructure
Internet of Things infrastructure

sensor system collecting road traffic and environment data at intersections, pedestrian crosswalks and

smart bus stations

Note 1 to entry: The collected data is transmitted to the monitoring and control centre and automated driving

buses (ADBs) directly through communication networks.
3.1.11
smart bus station

facility where an automated driving bus stops and passengers safely board, alight, and wait for an

automated driving bus

Note 1 to entry: The smart bus station is installed with a station kiosk and Internet of Things infrastructure to

communicate with the monitoring and control centre.
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ISO 21734-1:2022(E)
3.1.12
station kiosk

device that is installed at a smart bus station and assists passengers with their boarding reservations,

the payments and ticketing
3.1.13
pickup station

smart bus station which is designated by the monitoring and control centre and at which it is intended

that an automated driving bus (ADB) will pick up passengers when operating a demand-responsive

route
3.1.14
routine station

fixed smart bus station that is designated for automated driving buses (ADBs) as a location to stop at

for picking up and dropping off passengers
3.1.15
one-time boarding ticket
boarding ticket that is used for one round trip

Note 1 to entry: Depending on reservation methods, tickets can be either paper or electronic.

3.1.16
ADB users

general passengers who are the primary party receiving mobility services and legal entities providing

mobility services to the passengers including local authorities and private bus operators

3.1.17
passenger
one of the automated driving bus (ADB) users receiving ADB mobility services
3.1.18
operator

one of the users who is responsible for operating and managing the automated driving bus (ADB)

systems
3.1.19
operation manager

person responsible for monitoring the automated driving bus (ADB) fleet operation and responding to

emergencies in the monitoring and control centre
3.1.20
in-vehicle operation manager

person responsible for monitoring automated driving bus operations and responding to emergencies in

an automated driving bus (ADB) vehicle
3.1.21
on-demand route

operating measure with flexible schedule and route to respond to passengers’ demands within the

delineated service area
Note 1 to entry: Passengers may only board and alight at a smart bus station.

Note 2 to entry: An automated driving bus (ADB) can deviate from a fixed route to an on-demand route in

response to the passengers’ demand. However, the automated driving bus should stop at a smart bus station.

3.1.22
automated driving message
ADM

message carrying data collected by a suite of automated driving bus (ADB) sensors

Note 1 to entry: The types of messages and the data each message includes are as follows:

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ISO 21734-1:2022(E)

— ADB driving messages include speed, acceleration and deceleration, angular acceleration, etc.

— ADB positioning messages include latitude, longitude, global navigation satellite system mode, etc.

— Route messages include a route ID, stopovers, the destination, etc.

— Route following messages include orientation control, control speed, acceleration, brake, mission, etc.

— Object messages include object type, distance to object, etc.

— Decision messages include system decision messages such as departure, stop, waiting, transmission

information, etc.
— Sensor messages include fail or safe, rerun message, etc.

— Automated driving status messages include fail or safe, passenger information, etc.

3.1.23
automated driving service message
ASM

service message such as automated driving control, road driving and pedestrian protection, and the

collected information which includes service unique ID, service purpose and service provision location,

etc.
3.1.24
basic safety message
BSM

message providing basic information for safe driving such as communication status, weather

information, system status, etc.
3.1.25
emergency event message
EEM

message providing information for responding to the vehicle emergency and driving requirements

when operating

Note 1 to entry: The collected information includes emergency event ID, location, time of the emergency, etc.

3.1.26
routine data set

data set that the two components (automated driving bus and monitoring and control centre) regularly

exchange without a request from each side
3.1.27
event data set

data set provided when requested by automated driving buses (ADBs) or the monitoring and control

centre
3.1.28
backup data set

data sets stored once the automated driving buses (ADBs) finish one round of the route

3.1.29
target location

specific point on an automated driving bus route where an automated driving bus is aiming to move on

3.1.30
target vehicle

vehicle that can form a conflict with an automated driving bus by driving in opposite directions or

merging into the same lane, at the same location, and at the same time
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ISO 21734-1:2022(E)
3.1.31
target object

pedestrian, bicycle rider and other non-human object that can potentially form a conflict with an

automated driving bus (ADB)
3.2 Abbreviated terms
BIS bus information system
BMS bus management system
BRT bus rapid transit
DSRC dedicated short range communication
GNSS global navigation satellite system
IoT Internet of Things
LTE long term evolution
RSE roadside equipment
RSU roadside unit
SOH state of health for electric vehicle battery
TOD transport-oriented development
V2I vehicle to infrastructure
V2X vehicle to everything
WAVE wireless access for vehicle environment
4 General information
4.1 ISO 21734 series overview and structure

The ISO 21734 series specifies documents and standards related to the connectivity and safety

functions required to support the implementation of the ADB system in the public transport network.

Unlike autonomous driving vehicles which make operation manoeuvres based on their own sensor

data, ADBs are connected with the MC centre and Internet of Things (IoT) infrastructure for obtaining

information that is critical for ensuring safety but undetectable by their own sensors.

This document (ISO 21734-1) defines five components of the ADB system that are required for safe

operations, the objectives and scopes of performance tests in terms of connectivity and safety for ADB

operations, and service framework and use cases.

ISO 21734-2:— specifies the performance requirements and test procedures for ADBs to operate

in existing public transport systems. It specifies appropriate types of test methods and performance

standards to ensure the overall safety of public transport operations.

ISO/TR 21734-3:— specifies the service framework and uses cases as a technical reference for

field applications. The service framework is composed of software that utilizes components of ADBs,

1) Under preparation. Stage at the time of publication: ISO/AWI 21734-2:2022.
2) Under preparation. Stage at the time of publication ISO/DTR 21734-3:2022.
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ISO 21734-1:2022(E)

passengers, IoT infrastructure, smart bus stations, the MC centre and other elements for serving

passengers.
4.2 Purpose of the ISO 21734 series

The overall purpose of ISO 21734 series is to set performance standards, testing methods and

procedures for operating ADBs when adopted for a conventional bus system.

The purpose of ISO 21734–1 (this document) is to provide general information on the ISO 21734 series,

including the basic structure of the series. It further specifies five ADB system components that are

required for ADBs to operate in existing bus system and use cases.

The purpose of ISO 21734-2 is to specify performance requirements to be adopted safely as an ADB

system in terms of safety and connectivity and to specify test procedures for ensuring safety and

connectivity of the ADB system operation.

The purpose of ISO 21734-3 is to specify the ADB system service framework and use cases as a reference

for application.
5 ADB system Components
5.1 Overview

The ADB system shall consist of five components as shown in Figure 1: ADBs, the MC centre, IoT

Infrastructure, smart bus stations and ADB users.
Figure 1 — Five components of ADB system
5.2 ADB component

The ADB component is the most important component; all others except ADB user are supporting the

safe driving of ADBs. An ADB vehicle shall be designed for carriage of passengers with capacity of more

than nine persons and shall be embedded with level 4 automated vehicle technologies or higher based

on SAE J3016.
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ISO 21734-1:2022(E)

The ADB shall be capable of operating on fixed and on-demand routes, communicating with the

MC centre and IoT infrastructure, detecting traffic signals and other objects that may deter its safe

operation, allowing passengers to board and alight at a smart bus station regardle

...