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
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©  ISO 2008
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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 closing vehicle warning function only. These systems are intended to warn the
subject vehicle driver of target vehicles that are approaching the subject vehicle from the rear. Because these
systems are not required to provide warnings of target vehicles located adjacent to the subject vehicle, Type II
systems are recommended for use on vehicles that have side mirrors with a horizontal field of view of at least
45° on both sides of the vehicle. If these systems are used on other vehicles, the owner’s manual shall include
the following statement: “The driver must turn and look into the adjacent area before attempting a lane
change.” 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
no support for the areas adjacent to the subject vehicle. This system may not provide adequate warning for
very fast moving vehicles approaching from the rear.”
3.1.4 Type III systems
Type III systems provide the blind spot warning function and the closing vehicle warning function. These
systems are intended to warn the subject vehicle driver of target vehicles in the adjacent zones and target
vehicles which 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 may not provide adequate warning for very fast moving
vehicles approaching from the rear.”
3.2 Target vehicle closing speed classification
3.2.1 General
LCDAS of Types II and III are classified by the maximum target vehicle closing speed and the minimum
roadway radius of curvature as shown in Table 2. A system may belong to more than one of the types listed in
Table 2. For example, a highly capable system may meet or exceed the minimum requirements defined
individually for Types A, B and C.
Table 2 — Target vehicle closing speed classification
Maximum target vehicle Minimum roadway radius
closing speed of curvature
Type
m/s m
A 10 125
B 15 250
C 20 500
NOTE The maximum target vehicle closing speed has a direct effect on the required sensor range and/or acquisition
time. A higher closing speed will require a longer sensor range and/or a shorter acquisition time in order to detect the
target vehicle quickly enough to give the subject vehicle driver adequate warning. In addition, there is a relationship
between the maximum target vehicle closing speed and the roadway radius of curvature. For a given curve radius and a
typical subject vehicle speed, the closing speed of a target vehicle is limited by driving dynamics parameters.
3.2.2 Type A systems
Figure 6 shows the minimum required region of performance with regard to roadway radius of curvature and
target vehicle closing speed for a Type A system. These systems may be capable of operating on curved
roads with smaller radii. The subject vehicle driver shall be made aware of the limitations of the system, at
least in the owner’s manual. In particular, the owner’s manual shall include the following statement: “This
system may not provide adequate warning on curves tighter than X metres radius” where X is replaced by the
tightest curve radius for which the system is designed but not more than 125 m.

Key
X target vehicle closing speed, m/s
Y roadway radius of curvature, m
Figure 6 — Type A system minimum region of performance
3.2.3 Type B systems
Figure 7 shows the minimum required region of performance with regard to roadway radius of curvature and
target vehicle closing speed for a Type B system. These systems may be capable of operating on curved
roads with smaller radii. The subject vehicle driver shall be made aware of the limitations of the system, at
least in the owner’s manual. In particular, the owner’s manual shall include the following statement: “This
system may not provide adequate warning on curves tighter than X metres radius” where X is replaced by the
tightest curve radius for which the system is designed but not more than 250 m.
6 © ISO 2008 – All rights reserved

Key
X target vehicle closing speed, m/s
Y roadway radius of curvature, m
Figure 7 — Type B system minimum region of performance
3.2.4 Type C systems
Figure 8 shows the minimum required region of performance with regard to roadway radius of curvature and
target vehicle closing speed for a Type C system. These systems may be capable of operating on curved
roads with smaller radii. The subject vehicle driver shall be made aware of the limitations of the system, at
least in the owner’s manual. In particular, the owner’s manual shall include the following statement: “This
system may not provide adequate warning on curves tighter than X metres radius” where X is replaced by the
tightest curve radius for which the system is designed but not more than 500 m.

Key
X target vehicle closing speed, m/s
Y roadway radius of curvature, m
Figure 8 — Type C system minimum region of performance
4 Functional requirements
4.1 LCDAS state diagram
4.1.1 General
LCDAS shall at a minimum operate according to the state diagram in Figure 9.

Figure 9 — LCDAS state diagram
4.1.2 LCDAS inactive state
In the LCDAS inactive state the system shall give no warnings to the driver. This state may be a power off
state or a ready state. In a ready state the system may detect target vehicles, but shall not issue warnings
because the activation criteria are not met.
4.1.3 Activation criteria
4.1.3.1 General
When activated, the LCDAS shall transition from the LCDAS inactive state to the LCDAS active state. Several
activation criteria may be used at the same time. Potential activation criteria include but are not limited to the
following.
4.1.3.2 Continuous activation
The system may be active continuously (whenever the subject vehicle’s ignition is on).
4.1.3.3 Manual switch activation
The system may be activated manually, e.g. by a toggle switch, a tip switch or a menu-based user interface.
4.1.3.4 Turn signal activation
The system may be activated based on the subject vehicle turn signal status. For instance, if the left turn
signal is on, the system may be activated on the left side of the subject vehicle, while remaining inactive on
the right side of the subject vehicle.
8 © ISO 2008 – All rights reserved

4.1.3.5 Subject vehicle speed activation
The system may be activated based on the subject vehicle speed. If this is the case, then when the subject
vehicle speed is greater than or equal to a certain threshold speed the system will transition to the LCDAS
active state. The threshold speed shall be no more than 16,7 m/s (60 km/h).
4.1.4 LCDAS active state
4.1.4.1 General
In the LCDAS active state the system shall detect target vehicles.
4.1.4.2 Non-warning state
In the non-warning state the system is active, but the warning requirements are not fulfilled.
4.1.4.3 Warning state
4.1.4.3.1 General
In the warning state the system is active and the warning requirements are fulfilled.
4.1.4.3.2 Warning level 1 state
In the warning level 1 state the warning requirements are fulfilled but no evaluation criteria are met. The
warning given to the driver in this state shall be a cautionary warning, which is less urgent than the warnings
given in warning level 2 and any subsequent warning levels.
4.1.4.3.3 Evaluation criteria
4.1.4.3.3.1 General
Evaluation criteria are certain parameters that an LCDAS may monitor. Evaluation criteria should be useful in
determining the driver’s intention for changing the lane of travel. If one or more of these evaluation criteria are
met, then the system may transition from the warning level 1 state to warning level 2 and above. Several
evaluation criteria may be used at the same time. Potential evaluation criteria include but are not limited to the
following.
4.1.4.3.3.2 Turn signal evaluation
The system may evaluate the subject vehicle turn signal status. For instance, if the left turn signal is on, the
system may transition to warning level 2 or higher on the left side of the subject vehicle, while not affecting the
right side of the subject vehicle.
4.1.4.3.3.3 Subject vehicle steering input evaluation
The system may evaluate the steering input by the subject vehicle driver. If, for instance, the system
determines that the driver is initiating a lane change to the left, the system may transition to warning level 2 or
higher on the left side of the subject vehicle, while not affecting the right side of the subject vehicle.
4.1.4.3.3.4 Subject vehicle lane position evaluation
The system may evaluate the subject vehicle’s position and/or lateral motion within its lane. If, for instance,
the system determines that the subject vehicle is moving toward or into the lane to the left, the system may
transition to warning level 2 or higher on the left side of the subject vehicle, while not affecting the right side of
the subject vehicle.
4.1.4.3.3.5 Lateral clearance evaluation
The system may evaluate the lateral clearance to a target vehicle. If the system has the ability to measure
lateral clearance, then when the lateral clearance is less than a preset threshold value the system may
transition to warning level 2 or higher.
4.1.4.3.4 Warning level 2 and above
Warning level 2 and above are optional states. In these states the warning requirements are fulfilled and one
or more evaluation criteria are met. The warnings given to the driver in these states shall be imminent
warnings that are more urgent than the warning given in the warning level 1 state.
4.2 System performance
4.2.1 General
The following lines, illustrated in Figure 10, are needed for the description of the blind spot warning
requirements and the closing vehicle warning requirements. The designations right, left and behind refer to the
driving direction of the subject vehicle. The lane markings in Figure 10 are shown for reference only. All
dimensions are given with respect to the subject vehicle.
⎯ Line A shall be parallel to the trailing edge of the subject vehicle and a distance of 30,0 meters behind it.
⎯ Line B shall be parallel to the trailing edge of the subject vehicle and a distance of 3,0 meters behind it.
⎯ Line C shall be parallel to the leading edge of the subject vehicle and located at the centre of the 95th
percentile eyellipse.
⎯ Line D shall be the extension in both directions of the leading edge of the subject vehicle.
⎯ Line E shall be parallel to the centreline of the subject vehicle and located at the left outermost edge of
the subject vehicle’s body excluding the exterior mirror.
⎯ Line F shall be parallel to the centreline of the subject vehicle and a distance of 0,5 meter to the left of the
left outermost edge of the subject vehicle’s body.
⎯ Line G shall be parallel to the centreline of the subject vehicle and a distance of 3,0 meters to the left of
the left outermost edge of the subject vehicle’s body.
⎯ Line H shall be parallel to the centreline of the subject vehicle and a distance of 6,0 meters to the left of
the left outermost edge of the subject vehicle’s body.
⎯ Line J shall be parallel to the centreline of the subject vehicle and located at the right outermost edge of
the subject vehicle’s body excluding the exterior mirror.
⎯ Line K shall be parallel to the centreline of the subject vehicle and a distance of 0,5 meter to the right of
the right outermost edge of the subject vehicle’s body.
⎯ Line L shall be parallel to the centreline of the subject vehicle and a distance of 3,0 meters to the right of
the right outermost edge of the subject vehicle’s body.
⎯ Line M shall be parallel to the centreline of the subject vehicle and a distance of 6,0 meters to the right of
the right outermost edge of the subject vehicle’s body.
⎯ Line N shall be the extension in both directions of the trailing edge of the subject vehicle.
⎯ Line O shall be parallel to the trailing edge of the subject vehicle and a distance of 10,0 meters behind it.
10 © ISO 2008 – All rights reserved

Key
1 subject vehicle
2 centre of the 95th percentile eyellipse
3 left adjacent zone
4 right adjacent zone
Figure 10 — Warning requirements diagram
4.2.2 Minimum detectable target vehicle
LCDAS shall be capable of detecting target vehicles that are at least the size of a highway-legal motorcycle
with a rider.
4.2.3 Requirements for the blind spot warning function
4.2.3.1 Warning requirements for the blind spot warning function
4.2.3.1.1 General
The blind spot warning function shall provide coverage of the left and right adjacent zones. The lines
illustrated in Figure 10 are needed for the description of the blind spot warning requirements.
NOTE The adjacent zone coverage is intended to supplement the mirror coverage of the subject vehicle.
4.2.3.1.2 Left side blind spot warning requirements
Referring to Figure 10, a left side blind spot warning shall be issued to the subject vehicle driver if a target
vehicle satisfies all of the following conditions:
⎯ any part of the target vehicle is forward of line B;
⎯ the target vehicle is entirely behind line C;
⎯ the target vehicle is entirely to the left of line F;
⎯ any part of the target vehicle is to the right of line G.
If the zone defined by lines A, D, E and H does not contain target vehicles nor any parts thereof then a left
side blind spot warning shall not be issued.
See Annex A for blind spot warning example cases.
4.2.3.1.3 Right side blind spot warning requirements
Referring to Figure 10, a right side blind spot warning shall be issued to the subject vehicle driver if a target
vehicle satisfies all of the following conditions:
⎯ any part of the target vehicle is forward of line B;
⎯ the target vehicle is entirely behind line C;
⎯ the target vehicle is entirely to the right of line K;
⎯ any part of the target vehicle is to the left of line L.
If the zone defined by lines A, D, J and M does not contain target vehicles nor any parts thereof then a right
side blind spot warning shall not be issued.
See Annex A for blind spot warning example cases.
4.2.3.2 Optional blind spot warning suppression
If the subject vehicle is overtaking the target vehicle and the target vehicle has entered the adjacent zone from
the front, the blind spot warning may be suppressed for a period of no more than 2 s after the blind spot
warning is first required.
12 © ISO 2008 – All rights reserved

4.2.4 Requirements for the closing vehicle warning function
4.2.4.1 Warning requirements for the closing vehicle warning function
4.2.4.1.1 General
The closing vehicle warning function shall provide coverage of the left and right rear zones. The lines
illustrated in Figure 10 are needed for the description of the warning requirements. For systems having the
ability to estimate the geometry of the roadway, these lines may be defined to follow the curvature of the
roadway.
4.2.4.1.2 Left side closing vehicle warning requirements
Referring to Figure 10, a left side closing vehicle warning shall be issued to the subject vehicle driver if a
target vehicle satisfies all of the following conditions:
⎯ the target vehicle is entirely behind line B;
⎯ the target vehicle is entirely to the left of line F;
⎯ any part of the target vehicle is to the right of line G;
⎯ the target vehicle’s estimated time to collision is less than or equal to the value given in Table 3.
Table 3 — Closing vehicle warning time to collision by target vehicle closing speed classification
Maximum target vehicle closing
Time to collision
speed for full performance
Type
m/s s
A 10 2,5
B 15 3,0
C 20 3,5
For target vehicles in the left rear zone behind line A, a left side closing vehicle warning shall not be issued if
all target vehicles have estimated times to collision of 7,5 s or more.
For target vehicles located on or forward of line A, a left side closing vehicle warning shall not be issued if
either of the following conditions is true:
⎯ the target vehicle is entirely forward of line N;
⎯ no part of the target vehicle is located in the area between lines E and H.
4.2.4.1.3 Right side closing vehicle warning requirements
Referring to Figure 10, a right side closing vehicle warning shall be issued to the subject vehicle driver if a
target vehicle satisfies all of the following conditions:
⎯ the target vehicle is entirely behind line B;
⎯ the target vehicle is entirely to the right of line K;
⎯ any part of the target vehicle is to the left of line L;
⎯ the target vehicle’s estimated time to collision is less than or equal to the value given in Table 3.
For target vehicles in the right rear zone behind line A, a right side closing vehicle warning shall not be issued
if all target vehicles have estimated times to collision of 7,5 s or more.
For target vehicles located on or forward of line A, a right side closing vehicle warning shall not be issued if
either of the following conditions is true:
⎯ the target vehicle is entirely forward of line N;
⎯ no part of the target vehicle is located in the area between lines J and M.
4.2.4.1.4 Optional dual side closing vehicle warning
Referring to Figure 10, simultaneous closing vehicle warnings may be issued on both sides of the subject
vehicle if a target vehicle satisfies all of the following conditions:
⎯ a left side closing vehicle warning is not currently required (see 4.2.4.1.2);
⎯ a right side closing vehicle warning is not currently required (see 4.2.4.1.3);
⎯ any part of the target vehicle is between lines E and J;
⎯ the target vehicle is entirely behind line O;
⎯ the target vehicle’s estimated time to collision is less than or equal to the value given in Table 3.
4.2.4.2 Optional closing vehicle information
Visual information pertaining to one or more target vehicles (e.g. target vehicle location, closing speed, etc.)
may be presented to the subject vehicle driver at any time provided that this information is clearly
distinguishable from a warning indication.
4.2.5 Requirements for the lane change warning function
4.2.5.1 Warning requirements for the lane change warning function
The warning requirements for the lane change warning function consist of the combination of the warning
requirements for the blind spot warning function and the warning requirements for the closing vehicle warning
function. For a given situation, the blind spot warning requirements will give one of the following results: shall
give warning, might give warning, shall not give warning. For the same situation, the closing vehicle warning
requirements will also give one of the following results: shall give warning, might give warning, shall not give
warning. Based on these two results, the lane change warning function shall give warnings according to
Table 4.
Table 4 — Lane change warning requirements
Shall give blind spot Might give blind spot Shall not give blind spot
warning warning warning
Shall give closing vehicle Shall give lane change Shall give lane change Shall give lane change
warning warning warning warning
Might give closing vehicle Shall give lane change Might give lane change Might give lane change
warning warning warning warning
Shall not give closing
Shall give lane change Might give lane change Shall not give lane change
vehicle warning warning warning warning
14 © ISO 2008 – All rights reserved

4.2.6 System response time
The overall system response time from the time at which a target satisfies the warning requirements to the
time that the warning indication is activated shall be no more than 300 ms.
The overall system response time from the time at which a warning is no longer allowed to the time that the
warning indication is deactivated shall be no more than 1 s.
4.3 User interface
4.3.1 LCDAS status indication
4.3.1.1 General
There are two possibilities of indicating the LCDAS status. The system shall use at least one of the following
two possibilities: LCDAS driver selection indication or LCDAS active/inactive indication.
4.3.1.2 LCDAS driver selection indication
If the system can be manually activated and deactivated by the driver, then the driver’s selection shall be
indicated. This indication shall be visual. If the means to manually activate and deactivate the system is a
switch, and the switch position is clearly understood by the driver, then the switch may be considered to be
this indicator.
4.3.1.3 LCDAS active/inactive indication
The system shall indicate whether it is in the active or inactive state (see 4.1). This indication shall be visual.
4.3.2 LCDAS warning indication
4.3.2.1 General
A system warning shall indicate to the subject vehicle driver that a lane change manoeuvre will result in a
threatening situation. Referring to 4.1, the LCDAS warning indication is active in the warning state.
4.3.2.2 LCDAS warning indication method
In the warning level 1 state (see 4.1) the system warning indication shall be visual only. In warning level 2 and
above (see 4.1) the system warning indication may include visual, audible, and/or haptic warnings. It is
recommended that warnings in some way indicate the side on which the target vehicle is present. It is
recommended that visual warning indicators be placed in locations that will encourage mirror usage. Visual
warnings should be clearly distinguishable from other visual information in the vehicle. If an audible warning is
used, it should be clearly distinguishable from other audible signals in the vehicle. If a haptic warning is used,
it should be clearly distinguishable from other haptic signals in the vehicle.
4.3.3 LCDAS failure indication
A failure indication shall indicate to the subject vehicle driver that the LCDAS self-test function (see 4.5) has
detected a system malfunction.
The LCDAS failure indication shall be visual and/or audible, and shall clearly convey to the driver that there is
a system malfunction.
4.4 Operation with trailers
The dimensions given in the LCDAS warning requirements are based upon the subject vehicle alone, without
regard to any trailer that may be attached. If a trailer is attached to the subject vehicle the LCDAS shall
operate according to one of the following options (ranked in order of preference).
a) The system performs according to its normal capabilities.
NOTE The coverage provided by the system is not extended to account for the trailer.
b) If the system is not able to perform according to its normal capabilities, then the system indicates to the
driver that the system is unavailable or disabled.
c) The system does not operate correctly; however, in this case the subject vehicle’s owner’s manual
includes a notice stating that the system does not operate correctly while towing a trailer.
4.5 Self-test requirements
The system shall at a minimum provide the following self-test functions (at least after each system activation):
The system shall:
⎯ check for proper function of the major electronic components;
⎯ check for proper function of all sensor elements.
The system shall automatically execute the self-test functions listed above, and shall generate an LCDAS
failure indication (see 4.3.3) whenever a fault condition is detected.
5 Test requirements
5.1 Test target vehicle
For each of the following tests, the test target vehicle shall be a motorcycle with a rider. The test target vehicle
shall have the following dimensions. The length of the motorcycle shall be between 2,0 m and 2,5 m. The
width of the motorcycle at its widest point (not including the side mirrors) shall be between 0,7 m and 0,9 m.
The height of the motorcycle (not including the windscreen) shall be between 1,1 m and 1,5 m.
5.2 Environmental conditions
The test location shall be on a flat, dry asphalt or concrete surface. The ambient temperature during testing
shall be within the range of 10 °C ± 30 °C. The horizontal visibility range shall be greater than 1 km.
5.3 Blind spot warning test requirements
5.3.1 General
Subclauses 5.3.2 and 5.3.3 describe the minimum test requirements for a blind spot warning system (LCDAS
Type I).
16 © ISO 2008 – All rights reserved

5.3.2 Blind spot warning test measurement system
The test measurement system shall:
⎯ be completely independent of the blind spot warning system being tested;
⎯ be capable of measuring the longitudinal distance between the trailing edge of the subject vehicle and the
leading edge of the test target vehicle, if the test target vehicle is to the rear of the subject vehicle;
⎯ be capable of measuring the longitudinal distance between the leading edge of the subject vehicle and
the trailing edge of the test target vehicle, if the test target vehicle is forward of the subject vehicle;
⎯ be capable of measuring the lateral distance between the leftmost edge of the subject vehicle and the
rightmost edge of the test target vehicle, if the test target vehicle is to the left of the subject vehicle;
⎯ be capable of measuring the lateral distance between the rightmost edge of the subject vehicle and the
leftmost edge of the test target vehicle, if the test target vehicle is to the right of the subject vehicle;
⎯ be capable of measuring the time delay from the point at which the test target vehicle satisfies the
warning conditions to the point at which a warning is issued;
⎯ be capable of measuring the time delay from the point at which a warning is no longer allowed to the point
at which the warning is terminated.
For all of the test procedures, the test measurement system shall be capable of the following accuracies.
⎯ Distance measurement accuracy:
⎯ for distances less than 2 m the accuracy shall be 0,1 m or better;
⎯ for distances from 2 m to 10 m the accuracy shall be 5 % or better;
⎯ for distances greater than 10 m the accuracy shall be 0,5 m or better.
⎯ Time measurement accuracy:
⎯ for times less than 200 ms the accuracy shall be 20 ms or better;
⎯ for times from 200 ms to 1 s the accuracy shall be 10 % or better;
⎯ for times greater than 1 s the accuracy shall be 100 ms or better.
5.3.3 Blind spot warning test procedures
5.3.3.1 General
During all of the following tests, all relevant activation criteria shall be met.
5.3.3.2 Target vehicle overtaking subject vehicle
The purpose of this test is to check that the blind spot warning system gives warnings when required as the
target vehicle overtakes the subject vehicle. Referring to Figure 11 and the line definitions in 4.2, the test shall
be conducted as follows.
On a straight, flat test course the subject vehicle shall be driven in a straight line at a minimum steady speed
of 20 m/s. The test target vehicle shall be driven in a straight line as shown in Figure 11 so that its closing
speed is between 1 m/s and 3 m/s. Both vehicles shall be driven such that the lateral distance between the
outermost edge of the subject vehicle’s body (excluding the exterior mirror) and the centreline of the test
target vehicle is 2,0 m to 3,0 m. To begin the test, the test target vehicle shall be completely behind line A.
As the test target vehicle approaches and overtakes the subject vehicle, the system shall meet the following
test requirements.
⎯ The system shall give no warnings while the test target vehicle is completely behind line A.
⎯ After the test target vehicle crosses line A, the system shall initiate a warning on the correct side of the
subject vehicle no later than the time at which the leading edge of the test target vehicle crosses line B
plus the system response time given in 4.2.6.
⎯ The system shall sustain the warning at least until the leading edge of the test target vehicle crosses
line C.
⎯ The system shall terminate the warning no later than after the time at which the trailing edge of the test
target vehicle crosses line D plus the system response time given in section 4.2.6.
This test shall be repeated according to Table 5 for a total of twelve trials. During night time conditions, no
illumination shall be provided other than the standard headlamps and tail lamps of the subject vehicle and test
target vehicle. If it can be shown that the ambient light conditions have no effect on the system’s performance,
then the tester may choose to perform either the daytime tests or the night time tests for a total of six trials.
Table 5 — Blind spot warning target overtaking subject test trials
Day Night
Test target to left
3 trials 3 trials
...