ISO 22737:2021

INTERNATIONAL ISO
STANDARD 22737
First edition
Intelligent transport systems — Low-
speed automated driving (LSAD)
systems for predefined routes —
Performance requirements, system
requirements and performance test
procedures
Systèmes de transport intelligents — Systèmes de conduite
automatisée à basse vitesse pour des itinéraires prédéfinis (LSAD) —
Exigences de performance, exigences du système et procédures de test
de performance
PROOF/ÉPREUVE
Reference number
ISO 22737:2021(E)
©
ISO 2021

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ISO 22737:2021(E)

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© ISO 2021
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ISO 22737:2021(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Example use case for an LSAD system deployment . 4
6 LSAD system architecture . 5
7 Basic requirements . 6
7.1 General . 6
7.2 Minimum operating capabilities . 7
7.3 Operational design domains (ODDs) . 7
7.4 LSAD state transition diagram . 7
7.4.1 LSAD state functional descriptions . 8
7.4.2 LSAD state transition description: . 9
7.4.3 Possible extension of the LSAD state diagram to accommodate dispatcher
inputs .11
7.5 Communication requirements .11
8 Functional requirements .12
8.1 Determination of hazardous situation .12
8.1.1 Non-occluded view .12
8.1.2 Occluded view .13
8.2 Minimal risk manoeuvre (MRM) .14
8.3 Driving in the drivable area .14
8.4 Emergency stop (e-stop) .15
9 Performance requirements for the LSAD system .16
9.1 Maximum subject vehicle speed (V ) .16
SV_max
9.2 Obstacle detection requirements .16
9.2.1 Maximum pedestrian speed (V ) .16
ped_max
9.2.2 Maximum pedal cyclist speed (V ) .16
ps_max
9.2.3 LSAD system deceleration .16
10 System requirements .16
10.1 Recording data about a safety-critical event .16
11 Performance test procedures .17
11.1 General .17
11.2 Environmental parameters .17
11.3 Hazardous situation .17
11.3.1 Pedestrian as an obstacle .17
11.3.2 Pedal cyclist as an obstacle .19
11.3.3 Hazardous situation turning around a corner .22
11.3.4 False positive tests.24
11.4 Drivable area test .26
11.4.1 Test setup .26
11.4.2 Vehicle parameters .27
11.4.3 Evaluation path parameters .27
11.4.4 Environmental parameters .28
11.4.5 Pass criteria for unblocked drivable area .28
11.4.6 Pass criteria for blocked drivable area .28
11.5 Minimal risk manoeuvre (MRM) test.28
11.5.1 Test setup .28
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11.5.2 Vehicle parameters .29
11.5.3 Evaluation path parameters .29
11.5.4 Environmental parameters .29
11.5.5 MRM trigger .30
11.5.6 Pass criteria .30
Annex A (informative) Test speeds for hazardous situation tests .31
Annex B (informative) Example LSAD communication messages .33
Annex C (informative) Example LSAD system data recorder .34
Annex D (informative) LSAD system activities (experiment tests) in various countries .35
Bibliography .43
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ISO 22737:2021(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
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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
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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.
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ISO 22737:2021(E)

Introduction
The move towards automated driving systems is leading to a shift in the way people, goods and
services are transported. One such new mode of transport is low-speed automated driving (LSAD)
systems, which operate on predefined routes. LSAD systems will be used for applications like last-mile
transportation, transport in commercial areas, business or university campus areas and other low-
speed environments.
A vehicle that is driven by the LSAD system (which can include interaction with infrastructure) can
potentially have many benefits, like providing safe, convenient and affordable mobility and, reducing
urban congestion. It can also provide increased mobility for people who are not able to drive. However,
with different applications of LSAD systems in the industry worldwide, there is a need to provide
guidance for manufacturers, operators, end users and regulators to ensure their safe deployment.
The LSAD system requirements and procedures specified herein are intended to assist manufacturers
of the LSAD systems in incorporating minimum safety requirements into their designs and to allow
end users, operators and regulators to reference a minimum set of performance requirements in their
procurements.
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INTERNATIONAL STANDARD ISO 22737:2021(E)
Intelligent transport systems — Low-speed automated
driving (LSAD) systems for predefined routes —
Performance requirements, system requirements and
performance test procedures
1 Scope
This document specifies:
— requirements for the operational design domain,
— system requirements,
— minimum performance requirements, and
— performance test procedures
for the safe operation of low-speed automated driving (LSAD) systems for operation on predefined
routes. LSAD systems are designed to operate at Level 4 automation (see ISO/SAE DPAS 22736), within
specific operational design domains (ODD).
This document applies to automated driving system-dedicated vehicles (ADS-DVs) and can also be
utilized by dual-mode vehicles (see ISO 2575). This document does not specify sensor technology
present in vehicles driven by LSAD systems.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 19206-2, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for
assessment of active safety functions — Part 2: Requirements for pedestrian targets
ISO 19206-3, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for
assessment of active safety functions — Part 3: Requirements for passenger vehicle 3D targets
ISO 19206-4, Road vehicles — Test devices for target vehicles, vulnerable road users and other objects, for
assessment of active safety functions — Part 4: Requirements for bicyclist targets
ISO 26262 (all parts), Road vehicles — Functional safety
1)
ISO 21448:— , Road vehicles — Safety of the intended functionality
2)
ISO/SAE DPAS 22736:— , Taxonomy and definitions for terms related to driving automation systems for
on-road motor vehicles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/SAE DPAS 22736 and the
following apply.
1) Under preparation. Stage at the time of publication: ISO/DIS 21448:2021.
2) Under preparation. Stage at the time of publication: ISO/SAE DPAS 22736:2021.
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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
hazardous situation
condition whereby the position, orientation and motion of an obstacle (e.g. pedal cyclists, pedestrians,
vehicles, etc.) relative to the position, orientation and motion of the vehicle driven by the LSAD system,
can result in an imminent collision
3.2
predefined route
trajectory defined before start of a trip to be traversed by the vehicle driven by the LSAD system, from
a point of origin to one (or many) destination(s)
Note 1 to entry: A single trip of a vehicle driven by the LSAD system may have many destinations. A predefined
route has a length and curvature but not width.
3.3
minimal risk manoeuvre
MRM
tactical or operational manoeuvre triggered and executed by the LSAD system to achieve minimal risk
condition
3.4
trip segment
travel from point of origin to destination or from one destination to another destination in a trip
Note 1 to entry: A trip may comprise multiple trip segments.
3.5
drivable area
manoeuvrable area around the predefined route (3.2) where the LSAD system is capable of operating
Note 1 to entry: The width of the drivable area may vary along the predefined route.
3.6
pedal cyclist
human-vehicle combination consisting of a human riding on top of a wheel frame with a steering
mechanism, brakes, two pedals for propulsion (optionally with motor assist pedalling) that does not
require a licence for use on public roads
3.7
day-time
condition where the ambient illuminance is greater than 2 000 lx
3.8
night-time
condition where the ambient illuminance is less than 1 lx
3.9
standstill
vehicle state when vehicle speed is at 0 m/s
3.10
low-speed automated driving systems
LSAD
automated driving system that has a maximum speed of 8,89 m/s
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3.11
low ambient lighting condition
ambient light between day-time (3.7) and night-time (3.8)
4 Symbols and abbreviated terms
ϴ angle between pedestrian trajectory and vehicle trajectory while in straight section of the
evaluation path
ADS-DV automated driving system-dedicated vehicle
DDT dynamic driving task
e-stop emergency stop
LSAD low-speed automated driving
MaaS mobility as a service
MRC minimal risk condition
ODD operational design domain
R radius of curvature of trajectory in drivable area
RTI request to intervene
S width of drivable area
lat1
S lateral distance between SV and pedestrian starting point
lat2
S lateral distance between SV and target vehicles (TV and TV )
lat3 1 2
S width of reduced drivable area
lat4
S longitudinal distance of drivable area
long
S longitudinal distance of evaluation path from situation C
long2
S longitudinal distance between point 1 and point 4
long3
S longitudinal distance between point 1 and Pt.4 where MRM is triggered
long4
S longitudinal distance between Pt. 4 and end of evaluation path
long5
SV subject vehicle
T time taken by pedestrian to reach point 2
ped_to_Pt2
T time taken by pedal cyclist to reach point 2
pc_to_Pt2
TV target vehicle (1, 2)
(1, 2)
V2X vehicle to - X
V velocity for the LSAD system
LSAD
V maximum velocity for the LSAD system
LSAD_max
V velocity of pedal cyclist
pc
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V maximum velocity of pedal cyclist
pc_max
V velocity of pedestrian
ped
V velocity of pedestrian
ped_max
V maximum velocity of subject vehicle
sv_max
VRU vulnerable road users
DDT dynamic driving task
5 Example use case for an LSAD system deployment
Vehicles driven by LSAD systems may be used as a part of a larger (MaaS) system. Figure 1 depicts an
example system architecture of such a MaaS system. However, the scope of this document is restricted
to the LSAD system installed in a vehicle in Figure 1.
As per the example in Figure 1, the LSAD system receives a trip destination from the dispatcher via
wireless communication, which in turn receives a destination request from the user (through a web
portal or a mobile app. The dispatcher or the control centre processes the destination request and
provides a trip/trip segment confirmation to the user and commands the vehicle driven by the LSAD
system to proceed. The term "dispatcher" in this document refers to the driverless operation dispatcher
(see ISO/SAE DPAS 22736).
As there may be more than one predefined route to reach the destination, the selected predefined route
may be:
1) provided by the dispatcher/control centre;
2) selected by the user via a user-interface on a mobile app or on-board the LSAD system equipped
vehicle;
3) selected by the LSAD system itself.
The LSAD system periodically provides its status (e.g. system health, trip status) to the user and the
dispatcher/control server.
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Figure 1 — Example system architecture — LSAD in a MaaS system
6 LSAD system architecture
Figure 2 represents the system architecture of an individual LSAD system. Figure 2 also highlights the
components from the LSAD system architecture that are covered within the scope of this document.
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Key
functional requirements defined in this document
optional features not defined in this document
functional requirements not defined in this document
Figure 2 — Example system architecture — individual LSAD system
7 Basic requirements
7.1 General
The LSAD system shall perform the dynamic driving task (see ISO/SAE DPAS 22736). The implementation
of the strategic driving tasks (see ISO/SAE DPAS 22736) is left to the manufacturer’s discretion.
However, the LSAD system shall operate in predefined routes only. The maximum operational speed of
an LSAD system engaged vehicle shall be equal to or less than 8,89 m/s or 32 km/h. However, this may
be significantly reduced based on special conditions (selected as per the discretion of the driverless

operation dispatcher [ISO/SAE DPAS 22736]) mentioned in this document, for example time of day,
visibility, day of week, rainfall, snow, fog, ice on roads etc.).
The LSAD system shall use sensors in order to enable part of the dynamic driving task. This includes
detecting objects, vehicles, pedestrians, buildings, pathways, etc. Appropriate hazard analysis and
risk assessment shall be performed for the sensor performance and failures, and other safety critical
system elements. The LSAD system development shall be developed according to the ISO 26262 series
and ISO 21448.
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7.2 Minimum operating capabilities
Subject vehicles driven by the LSAD system shall be capable of performing the following functions:
a) follow a predefined route to the destination (8.3),
b) detect a hazardous situation (8.1),
c) initiate braking and/or steering, to mitigate and/or avoid collision with obstacles (9.1, 9.2),
d) perform minimal risk manoeuvre (8.2),
e) inform the dispatcher about the fault state of the LSAD system (e.g. binary flag) (8.4),
f) provide warnings to road users in case of a hazardous situation.
7.3 Operational design domains (ODDs)
Every LSAD system shall have its ODD defined by the manufacturer. The ODD limitations for an LSAD
system shall specify at least the following attributes:
a) Low speed: the speed of an LSAD system shall be equal to or less than 8,89 m/s or 32 km/h.
b) Areas of application: for example, either restricted access or dedicated roadways (public or
private), or pedestrian/bicycle pathways, or areas from which all or some specific categories of
motor vehicles are restricted. Restricted access roadways can be specified by lane markings or
speed restriction or physical demarcation. (See Annex D for examples).
c) Predefined routes: routes defined within the LSAD system before operation of the LSAD system.
An LSAD system shall only operate on the predefined routes. Predefined routes shall be defined
by relevant stakeholders in conjunction with each other (e.g. local authorities, service providers,
manufacturers, etc.). Any deviation from predefined routes shall be confirmed by the dispatcher to
not result in a hazardous situation.
d) Lighting conditions in the area of application.
e) Weather conditions.
f) Road conditions.
g) Presence or absence of VRUs.
h) Potential presence of static obstacles in the drivable area.
i) Connectivity requirements.
Either the LSAD systems or the dispatcher should select operating values (for a vehicle driven by the
LSAD system) within the boundaries of the predefined values of the ODD attributes for the specified
application based on current ODD conditions (e.g. foggy weather conditions, night-time lighting
conditions).
EXAMPLE A dispatcher or an LSAD system can decide to restrict the maximum allowable speed on a rainy
day to a lower speed as compared to a clear, sunny day.
7.4 LSAD state transition diagram
The LSAD system shall function according to the state transition diagram of Figure 3. Specific
implementation, beyond the description in Figure 3 shall be the responsibility of the manufacturer.
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Key
A1 power on and self-test passed
B1 system failure or power-off dispatcher command or power turned off
B2 ODD conditions are met and dispatcher has sent engage ADS command and ADS equipped vehicle has data
recording capability and has engaged it
C1 dispatcher disengage command
C2 passenger or dispatcher initiates emergency stop
C3 detection of hazardous situation which the LSAD system is unable to handle or DDT performance relevant
system failure or loss of safety critical V2X communications or imminent violation of ODD or safe to proceed
confirmation authorization not received from dispatcher
C4 vehicle is in standstill, i.e. 0 m/s
C5 confirmation to proceed to standby state by dispatcher
C6 vehicle is in standstill, i.e. 0 m/s, and confirmation to proceed to standby state by dispatcher
Figure 3 — LSAD state transition diagram
7.4.1 LSAD state functional descriptions
7.4.1.1 LSAD off
The LSAD system shall not perform any aspect of the dynamic driving task in the LSAD off state.
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7.4.1.2 LSAD standby
In LSAD standby state, the LSAD system shall:
a) Verify that ODD conditions are satisfied to enable a transition to LSAD active state.
b) Perform communications with dispatcher.
c) Remain in standstill.
LSAD standby state may receive an external operating command from the dispatcher selecting the
operating values (e.g. nominal or degraded) for the LSAD system when in DDT state.
Note that nominal mode suggests the ideal performance of the vehicle driven by the LSAD system.
Degraded mode suggests reduced performance on pre-defined vehicle parameters due to external or
the LSAD system’s internal conditions.
7.4.1.3 LSAD active
In LSAD active state, the LSAD shall perform
...