ISO 17387:2008

INTERNATIONAL ISO
STANDARD 17387
First edition
2008-05-01
Intelligent transport systems — Lane
change decision aid systems (LCDAS) —
Performance requirements and test
procedures
Systèmes intelligents de transport — Systèmes d'aide à la décision de
changement de voie — Exigences de performances et méthodes
d'essai
Reference number
©
ISO 2008
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2008
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Terms and definitions. 1
3 Classification. 4
3.1 Coverage zone classification . 4
3.2 Target vehicle closing speed classification. 5
4 Functional requirements. 8
4.1 LCDAS state diagram . 8
4.2 System performance . 10
4.3 User interface. 15
4.4 Operation with trailers. 16
4.5 Self-test requirements. 16
5 Test requirements. 16
5.1 Test target vehicle . 16
5.2 Environmental conditions. 16
5.3 Blind spot warning test requirements . 16
5.4 Closing vehicle warning test requirements . 24
5.5 Lane change warning test requirements. 29
Annex A (informative) Blind spot warning example cases . 34
Bibliography . 49

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 17387 was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
iv © ISO 2008 – All rights reserved

Introduction
Lane Change Decision Aid Systems (LCDAS) warn the driver against collisions that may occur due to a lane
change manoeuvre. LCDAS are intended to supplement the vehicle’s interior and exterior rear-view mirrors,
not eliminate the need for such mirrors. LCDAS are intended to detect vehicles to the rear and sides of the
subject vehicle (see Figure 1). When the subject vehicle driver indicates the desire to make a lane change, the
system evaluates the situation and warns the driver if a lane change is not recommended. LCDAS are not
meant to encourage aggressive driving. The absence of a warning will not guarantee that the driver can safely
make a lane change manoeuvre. The system will not take any automatic action to prevent possible collisions.
Responsibility for the safe operation of the vehicle remains with the driver.
NOTE Many figures in this document show vehicles on roadways with lane markings. This is not meant to imply that
lane marking recognition or lane detection is required for an LCDAS. The lane markings are drawn for reference only.

Key
1 subject vehicle
2 target vehicles
a
The shaded area illustrates the concept of one possible system. The actual requirements are given in Clause 4.
Figure 1 — LCDAS concept
INTERNATIONAL STANDARD ISO 17387:2008(E)

Intelligent transport systems — Lane change decision aid
systems (LCDAS) — Performance requirements and test
procedures
1 Scope
This International Standard specifies system requirements and test methods for Lane Change Decision Aid
Systems (LCDAS). LCDAS are fundamentally intended to warn the driver of the subject vehicle against
potential collisions with vehicles to the side and/or to the rear of the subject vehicle, and moving in the same
direction as the subject vehicle during lane change manoeuvres. This standardization addresses LCDAS for
use on forward moving cars, vans and straight trucks in highway situations.
This standardization does not address LCDAS for use on motorcycles or articulated vehicles such as
tractor/trailer combinations and articulated buses.
2 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
NOTE The figures illustrating the coverage zone definitions show the zone concept only. The actual requirements are
given in 4.2.
2.1
subject vehicle
vehicle equipped with the system in question and related to the topic of discussion
2.2
LCDAS target vehicle
any vehicle that is closing in on the subject vehicle from behind, or any vehicle that is located in one of the
adjacent zones
NOTE An LCDAS target vehicle is referred to as “target vehicle” in this document.
2.3
coverage zone
entire area to be monitored by an LCDAS, a system’s coverage zone consisting of a specific subset of the
following zones: left adjacent zone, right adjacent zone, left rear zone and right rear zone
NOTE A target vehicle located within the coverage zone will thus be detected by the system.
2.4
adjacent zones
zones to the left and right of the subject vehicle
See Figure 2.
NOTE The adjacent zones are intended to cover the lanes adjacent to the subject vehicle. However, the position and
size of the adjacent zones are defined with respect to the subject vehicle, and are independent of any lane markings.
Key
1 subject vehicle
2 left adjacent zone
3 right adjacent zone
Figure 2 — Adjacent zones
2.5
rear zones
zones that are behind and to the sides of the subject vehicle
See Figure 3.
NOTE The rear zones are intended to cover the lanes adjacent to the subject vehicle. However, the position and size
of the rear zones are defined with respect to the subject vehicle, and are independent of any lane markings.

Key
1 subject vehicle
2 left rear zone
3 right rear zone
Figure 3 — Zones
2.6
lateral clearance
〈of a target vehicle〉 lateral distance between the side of the subject vehicle and the near side of a target
vehicle
See Figure 4.
2 © ISO 2008 – All rights reserved

Key
1 subject vehicle
2 target vehicle
3 lateral clearance
Figure 4 — Lateral clearance
2.7
rear clearance
〈of a target vehicle〉 distance between the rear of the subject vehicle and the front of the target vehicle as
measured along a straight line, or optionally, as estimated along the target vehicle’s estimated path
See Figures 5 a) to 5 d).
NOTE This definition applies to target vehicles in the rear zones only.

a)  On a straight road measured along b)  On a straight road estimated along
a straight line target vehicle path

c)  On a curved road measured along d)  On a curved road estimated along
a straight line target vehicle path
Key
1 subject vehicle
2 target vehicle
3 rear clearance
Figure 5 — Examples of rear clearance
2.8
closing speed
〈of a target vehicle〉 difference between the target vehicle’s speed and the subject vehicle’s speed
NOTE This definition applies to target vehicles in the rear zones only. A positive closing speed indicates that the
target vehicle is closing in on the subject vehicle from the rear.
2.9
time to collision
estimated time that it would take a target vehicle to collide with the subject vehicle if the subject vehicle were
in the target vehicle’s path and the target vehicle’s current closing speed remained constant
NOTE Time to collision can be estimated by dividing a target vehicle’s rear clearance by its closing speed. This
definition applies to target vehicles in the rear zones only.
2.10
overtaking speed
〈of the subject vehicle〉 difference between the subject vehicle’s speed and the target vehicle’s speed when
the subject vehicle is overtaking the target vehicle
NOTE A positive overtaking speed indicates that the subject vehicle is moving faster than the target vehicle.
2.11
blind spot warning function
function that detects the presence of target vehicles in one or more of the adjacent zones and warns the
subject vehicle driver in accordance with the requirements given in Clause 4
2.12
closing vehicle warning function
function that detects closing vehicles in one or more of the rear zones and warns the driver in accordance with
the requirements given in Clause 4
2.13
lane change warning function
function that includes the blind spot warning function and the closing vehicle warning function
2.14
roadway radius of curvature
horizontal radius of curvature of the road on which the subject vehicle is travelling
3 Classification
3.1 Coverage zone classification
3.1.1 General
LCDAS are classified by the minimum required coverage as shown in Table 1; for example, a Type I system
shall provide coverage of at least the left and right adjacent zones.
Table 1 — Coverage zone classification
Left adjacent Right adjacent Left rear Right rear
Type Function
zone coverage zone coverage zone coverage zone coverage
Blind spot
I X X
warning
Closing vehicle
II  X X
warning
Lane change
III X X X X
warning
4 © ISO 2008 – All rights reserved

3.1.2 Type I systems
Type I systems provide the blind spot warning function only. These systems are intended to warn the subject
vehicle driver of target vehicles in the adjacent zones. These systems are not required to provide warnings of
target vehicles that are approaching the subject vehicle from the rear. The subject vehicle driver shall be
made aware of the limitations of this type of system, at least in the owner’s manual. In particular, the owner’s
manual shall include the following statement: “This system provides support only within a limited area beside
the vehicle. The system may not provide adequate warning for vehicles approaching from the rear.”
3.1.3 Type II systems
Type II systems provide the closi
...