ISO 21815-3:2023
(Main)Earth-moving machinery — Collision warning and avoidance — Part 3: Risk area and risk level for forward/reverse motion
Earth-moving machinery — Collision warning and avoidance — Part 3: Risk area and risk level for forward/reverse motion
This document defines requirements for collision warning systems (CWS) and collision avoidance systems (CAS) that address forward and reverse motion for: — earth-moving machinery as defined in ISO 6165, — mobile underground mining machinery as defined in ISO 19296, and — road construction machinery as defined in ISO 22242. This document does not consider machine height beyond that of height in travel position (e.g. dump body on dumper in lowered position) as established by machine manufacturer. This document covers collision avoidance by reducing speed, stopping, or inhibiting motion; it does not cover avoidance by automatic manoeuvring (e.g. steering) away from the intended object. Specific requirements for other types of machine motion are defined in the other parts of the ISO 21815 series. The system described in this document is intended to assist the operator of the machine. The responsibility for safe operation of the machine remains with the machine operator. This document is not applicable to collision warning and collision avoidance systems installed/manufactured before the date of its publication.
Titre manque — Partie 3: Titre manque
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21815-3
First edition
2023-08
Earth-moving machinery — Collision
warning and avoidance —
Part 3:
Risk area and risk level for forward/
reverse motion
Reference number
© ISO 2023
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
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Performance requirements . .7
4.1 General requirements . 7
4.2 Calculating CxS distance . 7
4.2.1 Forward/reverse motion . 7
4.2.2 Collision risk area reduction. 7
4.3 Determination of collision risk level . 8
4.4 Collision warning and collision avoidance action . 8
4.5 CxS action and expected machine speed behaviour . 8
4.5.1 General . 8
4.5.2 Requirement of D . 8
4.5.3 CxS configuration . 8
4.6 Collision warning system . 9
4.6.1 System functionality . 9
4.6.2 Discontinuation of warning signal and reactivation . . 9
4.6.3 Human interface requirements . 9
4.7 Collision avoidance system . 10
4.7.1 System functionality . 10
4.7.2 Discontinuation of collision avoidance action and reactivation . 10
4.7.3 Intervention indicator . 11
5 Time and distance calculation guidance .11
5.1 General . 11
5.2 CxS detection, determination and communication. 11
5.3 Action time (T ) and action distance (D ) . 11
CD CD
5.4 CWS action time (T ) .12
CD
6 Information for use .12
6.1 General .12
6.2 Operator’s manual .12
Annex A (normative) Determining of collision risk levels — forward/reverse motion .13
Annex B (normative) Limitations of use of CxS .16
Annex C (informative) Example calculation CxS distance for surface vehicles .22
Annex D (informative) Example calculations of CxS distance for underground mining
machine .24
Annex E (informative) Estimating the path .34
Annex F (informative) An approach for determining CxS configuration .38
Annex G (informative) Types of interventional collision avoidance actions . 44
Bibliography .48
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
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database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
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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 127, Earth moving machinery,
Subcommittee SC 2, Safety, ergonomics and general requirements.
A list of all parts in the ISO 21815 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.
iv
Introduction
The increasing use of detection systems and avoidance technology has been supporting operators to
safely operate machines in the field of mining and construction.
At the same time, there are demands to set standards for machines and systems detecting, alerting and
intervening to mitigate collision risk. This document addresses collision risk areas and collision risk
levels for machines utilizing detection systems and avoidance technology in the area of earth-moving
machinery that exhibit forward and reverse motion.
This document is a type-C standard as stated in ISO 12100.
This document is of relevance, in particular, for the following stakeholder groups representing the
market players with regard to machinery safety:
— machine manufacturers (small, medium, and large enterprises);
— health and safety bodies (regulators, accident prevention organisations, market surveillance etc.).
Others can be affected by the level of machinery safety achieved with the means of the document by the
above-mentioned stakeholder groups:
— machine users/employers (small, medium, and large enterprises);
— machine users/employees (e.g. trade unions, organizations for people with special needs);
— service providers, e. g. for maintenance (small, medium, and large enterprises);
— consumers (in case of machinery intended for use by consumers);
— providers of collision warning and avoidance technology;
— system integrators.
The above-mentioned stakeholder groups have been given the possibility to participate at the drafting
process of this document.
The machinery concerned and the extent to which hazards, hazardous situations, or hazardous events
are covered are indicated in the Scope of this document.
When requirements of this type-C standard are different from those which are stated in type-A or
type-B standards, the requirements of this type-C standard take precedence over the requirements of
the other standards for machines that have been designed and built according to the requirements of
this type-C standard.
This document addresses requirements for detecting, alerting and intervention in mitigating collision
risk.
There are currently two existing standards in the field: ISO 16001 and ISO 17757. These standards
provide guidance for visibility aids and object detection system and for autonomous and semi-
autonomous machines, however, there is currently no standard that describes collision risk awareness,
warning signals and collision avoidance actions of manually operated machinery when there is a risk of
collision.
v
INTERNATIONAL STANDARD ISO 21815-3:2023(E)
Earth-moving machinery — Collision warning and
avoidance —
Part 3:
Risk area and risk level for forward/reverse motion
1 Scope
This document defines requirements for collision warning systems (CWS) and collision avoidance
systems (CAS) that address forward and reverse motion for:
— earth-moving machinery as defined in ISO 6165,
— mobile underground mining machinery as defined in ISO 19296, and
— road construction machinery as defined in ISO 22242.
This document does not consider machine height beyond that of height in travel position (e.g. dump
body on dumper in lowered position) as established by machine manufacturer.
This document covers collision avoidance by reducing speed, stopping, or inhibiting motion; it does
not cover avoidance by automatic manoeuvring (e.g. steering) away from the intended object. Specific
requirements for other types of machine motion are defined in the other parts of the ISO 21815 series.
The system described in this document is intended to assist the operator of the machine. The
responsibility for safe operation of the machine remains with the machine operator.
This document is not applicable to collision warning and collision avoidance systems installed/
manufactured before the date of its publication.
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 6750-1, Earth-moving machinery — Operator's manual — Part 1: Contents and format
ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 21815-1, Earth-moving machinery — Collision warning and avoidance — Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12100, ISO 21815-1, and the
following 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
CxS distance
minimum distance for the CxS to complete detection (3.2), determination (3.3), action (3.6, 3.7), and
machine stopping distance (3.15), plus safe distance (3.10)
Key
1 machine
2 CxS distance
A – F see Table 1 and Table 2
Figure 1 — Graphical representation of CxS distance
Table 1 — CxS distance points
a
Point Description
A The point of the initial detection of the intended object by CxD
The point where the intended object is confirmed by the CxS (including debounce time)
B
NOTE For some systems this point cannot be quantified. There are no requirements for this
point.
The point where the CxS completes an assessment of risk level and the course of action is com-
C
municated to the operator (for CWS) or to the machine interface (for CAS)
The point where the operator has been provided sufficient time to react to the warning com-
D municated by the CWS or for the interventional collision avoidance action to be initiated on the
machine (for CAS)
E The point where the machine has fully stopped
F The position of the intended object
a
CWS specific notations are indicated with a single prime (’) and CAS specific are indicated with double prime (”)
throughout the document. No prime indicates CxS.
EXAMPLE A indicates CxS.
A’ specifies a CWS.
A” specifies a CAS.
Table 2 — CxS intervals
CxS distance CxS time inter-
a
Description
a a
interval val
D T detection (3.2)
AB AB
D T determination (3.3)
BC BC
D T action (3.6, 3.7)
CD CD
D T machine stopping distance (3.15)
DE DE
D T safe distance (3.10)
EF EF
a
CWS specific notations are indicated with single prime (’) and CAS specific indicated with
double prime (”) throughout the document. No prime indicated CxS.
EXAMPLE A-B indicates CxS
A’-B’ specifies a CWS
A”-B” specifies a CAS
Note 1 to entry: See Figure 1 for a graphical representation.
Note 2 to entry: The motion can be either forward or reverse (measured in meters).
Note 3 to entry: The values for D are typically larger for CWS than a CAS due to the slower action time of the
CD
operator.
Note 4 to entry: The first observable output of the CxS can be point C due to difficulty in measuring points A or B
without specialized equipment.
Note 5 to entry: Table 1 are points within the CxS distance.
Note 6 to entry: Table 2 are the intervals with the CxS distance.
Note 7 to entry: For a CWS, can be referred to as collision warning distance.
Note 8 to entry: For a CAS, can be referred to as collision avoidance distance.
Note 9 to entry: D is the period where the sensor algorithm is determining if the intended object is present.
AB
This interval can be important for the designer of the CxS but could be difficult for the system integrator to
measure or interpret.
3.2
detection
acknowledgement of intended object
[SOURCE: ISO 21815-1:2022, 3.11, modified — The phrase "by a CxS" was removed from the end of the
definition.]
3.3
determination
analysis of collision risk level of the intended object(s) by CxS
Note 1 to entry: Determination also includes the transmission of warning/interventional collision avoidance
action as appropriate for the collision risk level.
3.4
decision
acceptance of warning and selection of action by operator
Note 1 to entry: See Figure 5.
3.5
decision
acceptance of recommended interventional collision avoidance action by machine control
system
Note 1 to entry: Acceptance does not imply providing feedback to the CxS.
Note 2 to entry: See Figure 5.
3.6
action
performance of the evasive action by operator
3.7
action
performance of the interventional collision avoidance action by machine
3.8
safe offset distance
D
O
distance value that is determined by the authorized person to provide additional clearance around
intended object
3.9
error distance
D
I
error value in the system in measuring the distance D
AE
3.10
safe distance
D
EF
distance comprising the safe offset distance (3.8) plus the possible error in the CxS measurements
position variance
Note 1 to entry: Figure 2 illustrates safe distance.
Key
1 D (3.8)
O
2 D (3.9)
I
3 D (3.9) × 2
I
Figure 2 — Safe distance
3.11
possible path
space that the machine could occupy based on machine state, potential paths of motion, and machine
stopping distance
Note 1 to entry: Machine state includes velocity, current direction, etc.
Note 2 to entry: See Annex E for more information.
3.12
projected path
space that the machine movement will occupy if there is no change in machine motion inputs and
limited by machine stopping distance
Note 1 to entry: See Annex E for more information.
3.13
probable path
space where the machine is permitted to move based on site operation rules and limited by machine
stopping distance
Note 1 to entry: Multiple probable paths can have estimates of future likelihood.
Note 2 to entry: See Annex E for more information.
Note 3 to entry: It is assumed that the machine is under control of the operator.
3.14
expected path
space where the machine is anticipated and permitted to move based on the site operation rules and
machine operating context (e.g. lanes, loaded) and limited by machine stopping distance
Note 1 to entry: There is only one expected path.
Note 2 to entry: See Annex E for more information.
Note 3 to entry: It is assumed that the machine is under control of the operator.
3.15
machine stopping distance
D
DE
distance travelled by the machine from the point which the machine brake control actuation begins
(e.g. operator actuates the brakes for CWS or when intervention action commences for CAS) to the point
where the machine is fully stopped
Note 1 to entry: It is expressed in meters [m].
Note 2 to entry: Machine braking delay is included in the calculation or measurement of stopping distance.
Note 3 to entry: Operator action time is excluded from the calculation or measurement of stopping distance.
3.16
detection zone
space where intended objects are expected to be detected by the CxS with a specified reliability
Note 1 to entry: CxS device technology or detection methods impact the bounds of the space.
Note 2 to entry: Examples of typical detection zones shown in Figure 3.
Key
1 trapezoidal example
2 semi-circular example
3 complete circular example
Figure 3 — Examples of detection zones
3.17
intervention indicator
signal that the automatic interventional collision avoidance action is engaged
3.18
bi-directional traffic
traffic that flows in opposite directions on established travel routes
Note 1 to entry: Often described as right-hand traffic or left-hand traffic.
Note 2 to entry: Right-hand traffic keeps to the right of established travel routes. Opposing traffic passes along
the left side.
Note 3 to entry: Left-hand traffic keeps to the left of established travel routes. Opposing traffic passes along the
right side.
3.19
alarm fatigue
state when a person is overloaded with excessive number of notifications and starts to ignore these
notifications including potentially important ones
3.20
debounce time
period where the sensor algorithm is determining if the intended object is present
Note 1 to entry: This time could be inapplicable for certain types of systems.
3.21
collision risk level
CRL
value that is assigned to each intended object to determine if a collision is foreseeable based on the
current motion of the machine and the intended object
Note 1 to entry: See A.1.4 for additional information on collision risk levels.
Note 2 to entry: Adapted from ISO 21815-1:2022, 3.6.
4 Performance requirements
4.1 General requirements
Machinery shall conform with the safety requirements and/or protective/risk reduction measures of
this clause. In addition, the machine shall be designed according to the principles of ISO 12100:2010 for
relevant but not significant hazards which are not dealt with by this document.
CxS shall comply with the requirements of ISO 21815-1, in as far as those are not modified or added to
by the requirements in this document.
The CxS shall determine a collision risk level of each intended object and communicate the appropriate
action.
NOTE For multiple intended objects, see B.8.
The detection zone of CxD should be the same or larger than the collision risk area. However, due to
limits of the system, the detection zone may be smaller than the collision risk area. In that case, the
limits of the system shall be defined in the operator’s manual as a system limitation.
Annex B shall be used to provide information on the limitations of use of the CxS.
4.2 Calculating CxS distance
4.2.1 Forward/reverse motion
The CxS distance shall be long enough to allow a machine to stop to avoid a collision with an intended
object where earth-moving machinery (EMM) movement can occur.
NOTE 1 Examples of calculating CxS distances are provided in Annex C (surface machines) and Annex D
(underground machines).
NOTE 2 An example of an approach to determining CxD configuration parameters based on stopping
performance is provided in Annex F.
4.2.2 Collision risk area reduction
The collision risk area is determined by the limitations of physical kinematics (e.g. speed, turning
radius, angle, dimensions) of the machine. The size of the collision risk area may be reduced by knowing
the real-time value of kinematics (e.g. speed, turning angle).
Physical or virtual barriers can reduce the collision risk area, if the CxS is capable of considering them.
A CxS which has the ability to utilize information regarding projected path and expected path and their
interactions may be able to reduce the size of the collision risk area.
4.3 Determination of collision risk level
The CxS shall determine a collision risk level upon detection of each intended object within the detection
zone or collision risk area. The collision risk level is based on analysis of the current motion of machine
and possibility of a collision. For forward and reverse travel, Annex A shall be used to determine the
collision risk level.
NOTE 1 For other types of machine movement other parts of the ISO 21815 series can be used.
NOTE 2 For multiple intended objects, see B.8.
4.4 Collision warning and collision avoidance action
The CxS actions shall only occur for intended objects in the collision risk area.
NOTE There are several challenges (see Annex B) that can result in false positive detections (detecting
objects that do not have a high risk of collision) or false negative detections – missing real risks. False positives
could create alarm fatigue and result in operators ignoring real collision risks.
4.5 CxS action and expected machine speed behaviour
4.5.1 General
Figure 4 shows CxS device output in relation to distance travelled.
Key
v machine speed
P point (see Table 1)
a
CxS action.
Figure 4 — Expected machine speed
4.5.2 Requirement of D
The CxS may allow the means for the value to change in accordance with the worksite situation and
environment. This should be done by an authorized person.
4.5.3 CxS configuration
The CxS manufacturer shall communicate the typical delays in their system. If the CxS allows for
configurable parameters, the CxS manufacturer shall communicate the default values and how a system
integrator can change the default values.
If the system integrator changes the default values, the system integrator shall communicate the
configuration and assumptions. The following values shall be communicated:
— velocity,
— slope,
— T ,
AC
— T ,
CD
— and D .
DE
Table 3 is an example of the information.
Table 3 — Example of configuration and assumptions
Velocity Slope T T D
AC CD DE
[kph] [%] [s] [s] [m]
40 -10 0,300 2,5 130
10 -10 0,300 2,5 30
Ground conditions – dry and hard packed
Model of machine – truck model 123
Model of CxS – CwS model
CWS
CAS ESB SDB
NOTE For additional information, see Annex F, G.2 (ESB) and G.3 (CSB).
4.6 Collision warning system
4.6.1 System functionality
CWS shall provide warning(s) to assist operator in avoiding collision. The warning from the CWS shall
be initiated if the collision risk level with the intended object is at least equal to the threshold value of
collision risk level 3.
4.6.2 Discontinuation of warning signal and reactivation
Warning signals shall discontinue when the collision risk level of intended object has been reduced
below CRL-3. After the collision risk level of the intended object has become lower than CRL-3 but
returns to CRL-3 and above the threshold again, a warning signal shall be applied.
4.6.3 Human interface requirements
4.6.3.1 General
All visual, audible and haptic warnings shall be perceptible by the operator.
For devices that provide CWS functions, the operator action time shall be used in determining the
collision warning distance (see 5.3 and 5.4 for additional details).
A CWS shall provide warnings to the operator and may provide warnings to workers and other persons
present at the work site. If warnings are provided on levels, each warning signal shall be clearly
distinguishable from the others by the operator and correspond to the risk level.
The CWS shall notify for a period for time to allow the operator’s senses to recognize the CWS Action
(e.g. visual, audio).
4.6.3.2 Audible signals
Audible signals shall be set at and maintained, or should automatically adjust to, a level at least 3 dB
higher to the operator than the expected ambient noise level. Audible signals shall be selected so that
they are clearly audible to the operator.
The warning signal should align with the frequency range as defined ISO 16001:2017, 4.3.2.1.
Audible signals shall be distinguishable from other sounds (for example, warnings or machinery noise).
A voice message or melody type signal may be used for the warning signal. The voice message shall be
in the language understood by the operator. If multiple languages are available, then the system should
allow language selection.
Voice and melody signals can take an appreciable length of time to annunciate and for the operator to
comprehend the message, therefore, additional time shall be allowed for the operator action delay when
using voice or melody.
NOTE Distinctiveness of the alarm can be achieved by varying the spectral characteristics and the temporal
distribution of the signals (see ISO 9533).
4.6.3.3 Warning lights and visual devices
The warning lights and visual devices in the cab shall be located such that it is in the 120° arc centred
in front of the operator and shall be bright enough to be viewed under sunlight operating conditions.
Appropriate shielding may be used to reduce the effect of direct sunlight onto the visual devices.
The warning lights shall be distinguishable from other instrument panel warnings.
Visual devices may indicate recommended collision avoiding actions either by symbols and/or using
words such as “Emergency braking”, “Slow down”. If words are used, then the text or audible words
shall be in a language understood by the operator.
Visual devices may indicate direction of the other intended objects in surrounding area.
4.7 Collision avoidance system
4.7.1 System functionality
The collision avoidance system shall provide an interventional collision avoidance action (e.g. braking,
inhibiting motion, slowing down) to help the operator to avoid or mitigate risk of collision. An
appropriate level of intelligence should be provided in the system for determination of the collision risk
levels and the decision of the appropriate automatic actions.
The system may allow operator’s intentional control to override automatic interventional action
if appropriate. If the CAS is also equipped with CWS, the CWS may warn before the automatic
interventional action is initiated. The action from the CAS shall be initiated if the collision risk level
with the intended object is at least equal to the threshold value of collision risk level 4.
The system shall not override the operator control if braking by the operator is greater than that of the
system. For additional information on types of braking see Annex G.
4.7.2 Discontinuation of collision avoidance action and reactivation
The detail of discontinuation and reactivation of collision avoidance or mitigation action shall be
defined by the system integrator, based on the information provided by the CxS manufacturer and the
machine manufacturer, and shall be documented in the information for use.
To prevent a possible rollaway condition, the CxS should require the operator to act (e.g., set parking
brake) prior to allowing the CAS braking to discontinue.
4.7.3 Intervention indicator
An intervention indicator shall be provided. The intervention indicator shall occur no later than the
initiation of the interventional collision avoidance action (see Annex G).
5 Time and distance calculation guidance
5.1 General
The CxD distance may be subdivided into discrete parts based on CxS detection and determination
(D ), action (D ), and machine stopping distance (D ) as shown in Figure 5.
AC CD DE
Key
1 operator or machine control system action
Figure 5 — Subdivision of CxS distance into discrete parts
Annex C and Annex D show an example of the calculation.
5.2 CxS detection, determination and communication
The T is the total time from initial detection of the intended object to communicating the action. It
AC
comprises the time to detect a potential object and confirm this as an intended object (T ) and time to
AB
analyse the collision risk, determine recommended action and communicate external to the CxS (T ).
BC
D = v * T (1)
AC a AC
NOTE 1 v units is in meters/seconds.
a
NOTE 2 T units is in seconds.
AC
NOTE 3 D units is in meters.
AC
5.3 Action time (T ) and action distance (D )
CD CD
The action time T is the time while the machine control system or the operator takes action.
CD
D = v * T (2)
CD a CD
NOTE 1 v units is in meters/seconds.
a
NOTE 2 T units is in seconds.
CD
NOTE 3 D units is in meters.
CD
5.4 CWS action time (T )
CD
Depending on how the action is communicated, the decision by the operator requires time to recognize
the impending collision, apply the controls (e.g. apply brake, steer around) or determine no action is
necessary as shown in Table 4.
Table 4 shows example of calculating operator action time.
Table 4 — Example action times
Operator activity Min. time [s] Cumulative [s]
Recognition of impending collision and deci-
1,5 1,5
sion
Control action done by the operator 1,24 2,74
NOTE 1 Times in this table are defined in Table B.1 (Reference [10]).
NOTE 2 These times are indicative times and can vary based on several factors (e.g. age, health, complexity of
control action)
6 Information for use
6.1 General
Information for use shall be provided in accordance with ISO 12100:2010, 6.4.
6.2 Operator’s manual
Information for use shall be included in the operator’s manual and shall use ISO 6750-1 for guidance.
This information shall include the following as applicable:
— descriptions of symbols that are displayed to the operator and what action is required;
— descriptions of error messages that are displayed to the operator and what action is required;
— descriptions of warning messages that are displayed to the operator and what action is required;
— descriptions of calibration procedures that the operator is required to perform.
Annex A
(normative)
Determining of collision risk levels — forward/reverse motion
A.1 Collision risk levels
For forward/reverse motion there are multiple levels of risk. For all figures, the path shown is the
expected path, but it could also be all types of paths as defined in Annex E.
A.1.1 Collision risk level – Not applicable
The CxS determines there is no risk of a collision as there is no intended object as shown in Figure A.1.
The CRL is defined as (NA).
Figure A.1 — Risk level NA
A.1.2 Collision risk level 1
The risk of collision is not possible based on expected path of the machine and the location of the
intended object (e.g. Figure A.2).
Key
1 expected path
2 barrier (e.g. berm, wall)
3 intended object
NOTE The example shows a barrier but it is not required to be a valid example.
Figure A.2 — Collision risk level 1
A.1.3 Collision risk level 2
The risk of collision is possible, if the movement is initiated or continues in the same expected path but
no action is needed as shown in Figure A.3.
NOTE 1 CWS can make the operator aware of the intended object.
NOTE 2 CAS does not need to initiate interventional action, e.g. speed reduction.
Figure A.3 — Collision risk level 2
A.1.4 Collision risk level 3
The risk of collision is possible, if the movement is initiated or continues in the same expected path but
the operator has time to take action as shown in Figure A.4. The operator shall be made aware of the
intended object.
NOTE CAS could initiate interventional action, e.g. speed reduction.
Figure A.4 — Collision risk level 3
A.1.5 Collision risk level 4
The risk of collision is possible, if the movement is initiated or continues in the same expected path, but
the CAS shall automatically take action as shown in Figure A.5.
NOTE 1 The CWS informing the operator does not have time to avoid the intended object by only braking.
NOTE 2 An alternative motion can be used to avoid the intended object (e.g. steer around, raise bucket).
NOTE 3 The CAS can react fast enough by applying interventional action control (e.g. brake, motion inhibition).
Figure A.5 — Collision risk level 4
A.1.6 Collision risk level 5
The risk of collision cannot be avoided, if the movement is initiated or continues in the same state (e.g.
relative speed, direction, etc.) as shown in Figure A.6.
NOTE 1 An alternative motion can be used to avoid the intended object (e.g. steer around, raise bucket).
However, the machine is not able to react fast enough by only applying interventional action control (e.g. brake,
motion inhibition).
Figure A.6 — Collision risk level 5
A.2 Comparison of risk levels
Table A.1 compares the risk levels.
Table A.1 — Comparison of collision risk levels
Existence
Collision Possible risk of Required collision
of intend-
risk level collision avoidance action
ed object
NA No No No
1 Yes No No
2 Yes Yes No
3 Yes Yes CWS, CAS (CSB, SDB)
4 Yes Yes CAS (ESB, TIC)
5 Yes Yes -
NOTE 1 CSB is controlled stop braking.
NOTE 2 SDB is slow down braking.
NOTE 3 ESB is emergency stop braking.
NOTE 4 See Annex G for more information.
NOTE 5 On risk level 5 a CAS that only does braking will not prevent
the collision.
NOTE 6 TIC will occur at collision risk level 4.
Annex B
(normative)
Limitations of use of CxS
B.1 General
The following shall be considered in the development of the system and implementation.
Several challenges exist on assigning CRLs. These challenges can result in false positive CxS actions or
false negative CxS actions. Too many CxS false positives create alarm fatigue and result in operators
ignoring risk and create brake events that could create physical fatigue for the operators. False
negatives CxS actions could result in collision.
B.2 Distance
The minimum distance at which an object would need to be detected could exceed the distance at which
objects can be detected when the machines are traveling.
The CxS supplier shall provide information that describes the limits of detection and the configuration
parameters that allow the CxS actions to be matched to the slow down and braking characteristics of a
machine fitted with a CxD.
B.3 Environmental obscurants
Obscurants (e.g. rain, dust, EMI) can cause the object to be missed or cause the system to be non-
functional which could result in false actions.
The CxS supplier shall provide information on the limitations of the system in the presence of
environmental obscurants.
B.4 Terrain
The terrain of the collision risk area could degrade the performance of the system. Objects on uneven
terrain (e.g. slopes, ruts), around blind curves (e.g. switchbacks) could result in false actions.
B.5 Close proximity
Machines frequently work in close proximity within the determined collision risk area to other objects
on job-site to complete work tasks. Creating a system that can assign appropriate collision risk levels to
the intended objects allowed in close proximity could be difficult (e.g. wheel loader and a truck).
The CxS supplier shall define the limitations for use of the CxD when working in close proximity to
other objects.
B.6 Voids
Detecting a void requires the perception system to analyse the terrain and create a risk level based
strictly on the terrain.
The CxS supplier shall define the capability for detection and assessment of the risk level for voids in
the limitations for use.
B.7 Diverse objects
The types of objects are diverse. A technology that is sufficient for detecting one type of object could be
insufficient for detecting a different type of object. A complex system could fuse multiple technologies
together to address gaps.
The following are high level types of objects:
— earth-moving machinery;
— light vehicles;
— human;
— others (e.g. infrastructures, environment, voids).
The CxS supplier shall define the capability for detection and assessment of supported object types in
the limitations for use.
B.8 Multiple concurrent collision risk levels
There will be situations where there will be multiple objects that need be evaluated simultaneously as
shown in Figure B.1. The system should analyse each object in the collision risk area, assign a risk level
to each intended object and take appropriate action.
The system supplier shall communicate the limitations of concurrent risk levels.
Key
1 risk level 4
2 risk level 2
Figure B.1 — Multiple concurrent risk levels
B.9 Changing risk levels
Collision risk levels can change based on the movement of the machine and the object as shown in
Figure B.2.
Key
1 risk level 1
2 risk level 5
Figure B.2 — Changing risk level
The CxS supplier shall define the limitations for use of the CxD when rapidly changing risk levels are
present.
B.10 Instrumented vs non-instrumented objects
Some CxS can rely on the instrumentation of the objects to be detected to enable or improve the
detection of those objects. Common examples of instrumentation include coverage with reflective
material, addition of RFID tags and active reporting of GNSS position.
When CxS rely on the instrumentation of specific objects to meet a required detection rate, controls
shall be put in place to detect and correct failures of the instrumentation.
Administrative controls should not be presumed infallible or having a success rate superior to reality.
The CxS supplier shall define the ability and/or limitations to detect instrumented or non-instrumented
object.
B.11 Controlled vs uncontrolled site
On a controlled site, it is possible to ensure that objects (e.g. personnel and equipme
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