ISO 21202:2020

Intelligent transport systems — Partially automated lane change systems (PALS) — Functional / operational requirements and test procedures

This document contains the basic control strategy, minimum functionality requirements, basic driver interface elements, minimum requirements for reaction to failure, and performance test procedures for PALS. PALS perform part or all of lane change tasks under the driver's initiation and supervision. PALS are intended to function on roads with visible lane markings, where non-motorized vehicles and pedestrians are prohibited (e.g. access controlled highway), and to perform a lane change into a lane with traffic moving in the same direction. Support on sections of roadway with temporary or irregular lane markings (such as roadwork zones) is not within the scope of this document. This document does not describe functionalities based on combinations with longitudinal control systems such as those standardized in ISO 22839 (FVCMS) or ISO 15622 (ACC). The driver always assumes responsibility for this system and the driver's decisions and operations take priority at all times. Use of PALS is intended for light-duty and heavy-duty vehicles (heavy trucks and buses). This document does not address any functional or performance requirements for detection sensors, nor any communication links for co-operative solutions.

Systèmes de transport intelligents — Systèmes de changement de voie partiellement automatisés (PALS) — Exigences fonctionnelles et opérationnelles et procédures d’essai

General Information

• Status: Published
• Publication Date: 22-Apr-2020
• 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 14 - Vehicle/roadway warning and control systems
• Current Stage: 6060 - International Standard published
• Start Date: 22-Apr-2020
• Due Date: 14-Nov-2020
• Completion Date: 23-Apr-2020

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 21202
First edition
2020-04
Intelligent transport systems —
Partially automated lane change
systems (PALS) — Functional /
operational requirements and test
procedures
Systèmes de transport intelligents — Systèmes de changement de
voie partiellement automatisés (PALS) — Exigences fonctionnelles et
opérationnelles et procédures d’essai
Reference number
ISO 21202:2020(E)
©
ISO 2020

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ISO 21202:2020(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
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ii © ISO 2020 – All rights reserved

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ISO 21202:2020(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
4.1 Symbols . 3
4.2 Abbreviated term . 3
5 Classification . 4
5.1 General . 4
5.1.1 Type I systems . 4
5.1.2 Type II systems . 4
6 Requirements . 5
6.1 General . 5
6.2 Functionality . 5
6.3 State transitions . 6
6.3.1 General. 6
6.3.2 PALS off state . 6
6.3.3 Transition from PALS off state to PALS stand-by state . 6
6.3.4 Transition from PALS stand-by state to PALS off state . 6
6.3.5 PALS stand-by state . 6
6.3.6 PALS active state. 6
6.3.7 Transition from PALS stand-by state to PALS active state . 7
6.3.8 Transition from PALS active state to PALS stand-by state . 7
6.3.9 Transition from PALS active state to PALS off state . 7
6.4 Driver interface and override capabilities . 7
6.4.1 System reaction . 7
6.4.2 Display elements . 8
6.5 Minimum performance . 8
6.5.1 Duration of the lane change manoeuvre . 8
6.5.2 Velocity for PALS operation . 8
6.5.3 Operational limit . 8
6.6 Failure reactions . 8
7 Performance evaluation test methods . 9
7.1 Environmental conditions . 9
7.2 Test course conditions . 9
7.3 Test vehicle conditions . 9
7.4 Test system installation and configuration . 9
7.5 Test procedures . 9
7.5.1 Parameters recoverable from data record . 9
7.5.2 Lane change test (types I and II) .10
7.5.3 Gap search test (type II only) .11
Bibliography .13
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ISO 21202:2020(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
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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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
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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 21202:2020(E)

Introduction
In general, driving assist systems and automated driving systems equipped in a vehicle reduce the
burden of the drivers and contribute to safe driving. For a lane change operation, there are many
drivers who are not good at performing a lane change. To support such drivers, Partially Automated
Lane Change Systems (PALS) execute an automatic lane change manoeuvre following the request of
the driver and under the supervision of the driver, on a road with visible lane markings, where non-
motorized vehicles and pedestrians are prohibited.
PALS acquire information not only on the position of the vehicle within the lane, but also on adjacent
lanes and obstacles in the vicinity of the subject vehicle (SV). PALS evaluate whether or not a lane change
to an adjacent lane is possible and send commands to the actuators which control lateral movement
of the vehicle to perform a lane change. This document specifies how PALS support drivers for a lane
change and describes PALS' operations.
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INTERNATIONAL STANDARD ISO 21202:2020(E)
Intelligent transport systems — Partially automated
lane change systems (PALS) — Functional / operational
requirements and test procedures
1 Scope
This document contains the basic control strategy, minimum functionality requirements, basic driver
interface elements, minimum requirements for reaction to failure, and performance test procedures
for PALS.
PALS perform part or all of lane change tasks under the driver’s initiation and supervision. PALS
are intended to function on roads with visible lane markings, where non-motorized vehicles and
pedestrians are prohibited (e.g. access controlled highway), and to perform a lane change into a lane
with traffic moving in the same direction. Support on sections of roadway with temporary or irregular
lane markings (such as roadwork zones) is not within the scope of this document.
This document does not describe functionalities based on combinations with longitudinal control
systems such as those standardized in ISO 22839 (FVCMS) or ISO 15622 (ACC).
The driver always assumes responsibility for this system and the driver’s decisions and operations take
priority at all times.
Use of PALS is intended for light-duty and heavy-duty vehicles (heavy trucks and buses).
This document does not address any functional or performance requirements for detection sensors,
nor any communication links for co-operative solutions.
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 15037-1, Road vehicles — Vehicle dynamics test methods — Part 1: General conditions for passenger cars
ISO 15037-2, Road vehicles — Vehicle dynamics test methods — Part 2: General conditions for heavy
vehicles and buses
ISO 17387, Intelligent transport systems — Lane change decision aid systems (LCDAS) — Performance
requirements and test procedures
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/
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ISO 21202:2020(E)

3.1
subject vehicle
SV
vehicle equipped with the system in question and related to the topic of discussion
3.2
PALS state
one of several stages or phases of the system operation flow
Note 1 to entry: See Figure 1.
3.3
PALS off state
PALS state when the system is switched off
3.4
PALS stand-by state
PALS state when the system is switched on, but the activation criteria are not all met
3.5
PALS active state
PALS state when the system is switched on and the activation criteria are met
3.6
lane
one of the longitudinal strips into which a roadway is divided by lane markings (3.7)
3.7
lane marking
delineators, markings, or Botts’ dots intentionally placed on the borderline of the lane (3.6)
3.8
lane change manoeuvre
lateral movement which the system automatically executes to change lanes (3.6) from its initial lane to
an adjacent lane
3.9
lane change function
function of the system which includes both gap-searching and lane change manoeuvre (3.8)
3.10
time gap
value calculated from vehicle speed, v, and clearance, c, by the Formula: t = c/v
gap
Note 1 to entry: see Figure 1
Figure 1 — Time gap
3.11
time to collision
TTC
estimated time that it would take a target vehicle to collide with the SV if the SV were in the target
vehicle’s path and the target vehicle’s current closing speed remains constant
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ISO 21202:2020(E)

3.12
overtaking speed
difference between the SV’s speed and the target vehicle’s speed when the SV is overtaking the
target vehicle
Note 1 to entry: A positive overtaking speed indicates that the SV is moving faster than the target vehicle.
3.13
gap searching
system function to search for sufficient gap between the SV and the other vehicle(s) in the adjacent
target lane
4 Symbols and abbreviated terms
4.1 Symbols
See Table 1.
Table 1 — Symbols
Symbol Definition
Maximum lateral acceleration which is allowed to be induced by a lane change
A
PALS,l,max
manoeuvre
J Maximum lateral jerk which is allowed to be induced by a lane change manoeuvre
PALS,l,max
V Maximum SV speed which PALS is required to function
max
V Minimum SV speed which PALS is required to function
min
V Velocity of SV
sv
V Velocity of the rearward vehicle
rv
V Velocity of the forward vehicle
fv
Distance between the front edge of the rearward vehicle and the rear edge
D
r
of the SV
Distance between the rear edge of the forward vehicle and the forward edge
D
f
of the SV. The distance is equivalent to V × T
sv f.
T Time gap between the forward vehicle and the SV
f
T TTC between the rearward vehicle and the SV
col,r
Time from the initiation of the lane change function to the start of the lane
T change
I,S
manoeuvre itself, in a free gap available condition
4.2 Abbreviated term
ACC Adaptive cruise control
HMI Human-machine interface
LCDAS Lane Change Decision Aid Systems
SV Subject vehicle
TTC Time to collision
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ISO 21202:2020(E)

5 Classification
5.1 General
PALS are classified into two types by different tasks split between system and driver as shown in
5.1.1, and 5.1.2, and by a modified sequence of operations. In both types, the lane change manoeuvre
is initiated and supervised by the driver and is terminated when the SV is brought totally inside the
target lane.
In Type I systems, the driver intends to promptly change the lane as the driver evaluates the target lane
to be free and the PALS receive a driver command to perform the lane change manoeuvre. The system
performs the lane change unless it detects an adjacent vehicle that obstructs the lane change.
In Type II systems, the driver intends to change the lane as soon as a sufficient gap in the target lane
becomes available. The driver authorizes the system to search for a
...