ISO/PRF 23792-1

International
Standard
ISO 23792-1
First edition
Intelligent transport systems —
Motorway chauffeur systems
(MCS) —
Part 1:
Framework and general
requirements
Systèmes de transport intelligents — Systèmes de conduite
automatisée sur voie à chaussée séparée (MCS) —
Partie 1: Cadre et exigences générales
PROOF/ÉPREUVE
Reference number
ISO 23792-1:2026(en) © ISO 2026

ISO 23792-1:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
ISO 23792-1:2026(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 4
5 Characteristics of motorway chauffeur systems (MCS) . 4
5.1 General .4
5.2 Operational design domain (ODD) .4
5.2.1 General .4
5.2.2 Roadway physical characteristics .5
5.2.3 Traffic in the surrounding environment .6
5.2.4 Abnormalities in roadway operational condition . .6
5.2.5 Ambient environmental conditions .6
5.3 System functionalities .6
5.3.1 General .6
5.3.2 Basic functionalities to realize in-lane operation .7
5.3.3 Lane changing functionalities .7
5.4 Classification .7
5.5 System limitations .8
5.6 Providing information to the user .8
6 General system requirements . 8
6.1 Operating conditions .8
6.1.1 General .8
6.1.2 Engagement conditions .8
6.1.3 Disengagement-triggering conditions .8
6.1.4 Direct disengagement conditions .8
6.2 State transition .9
6.2.1 General .9
6.2.2 Off state .9
6.2.3 Standby state .10
6.2.4 Nominal operation state .11
6.2.5 Requesting fallback state. 12
6.3 System functions . 13
6.3.1 General . 13
6.3.2 Object and event detection and response (OEDR) . 13
6.3.3 Vehicle motion control (VMC) .14
6.3.4 Generation of request to intervene (RTI) .14
6.3.5 Status indication . 15
6.3.6 User control interface .16
6.3.7 Fallback-ready user (FRU) input detection .17
6.3.8 Motorway chauffeur system (MCS) monitoring the fallback-ready user (FRU) .18
6.3.9 Subject vehicle condition monitor .18
6.3.10 Motorway chauffeur system (MCS) condition monitor .18
6.3.11 Localization.18
6.3.12 External warning generation .18
6.3.13 Function required for route-following functionalities .18
6.3.14 Related functions .19
6.4 Requirements for continuing operation after detecting disengagement-triggering
conditions .19
6.4.1 General .19
6.4.2 Classification of adverse situations .19
6.4.3 Responses to adverse situations . 20
PROOF/ÉPREUVE
iii
ISO 23792-1:2026(en)
6.5 Misuse countermeasures .21
6.5.1 General .21
6.5.2 Hazardous situations involving reasonably foreseeable misuse .21
7 Minimum performance requirements of the dynamic driving task (DDT) .21
7.1 General .21
7.2 Following traffic rules . 22
7.3 Operating speed range . 22
7.4 Normal operation . 22
7.4.1 General . 22
7.4.2 Sustained longitudinal vehicle motion control . 22
7.4.3 Sustained lateral vehicle motion control . 23
7.4.4 Crash avoidance . 23
7.5 Performance-impaired operation .24
7.6 Reaction to unresponsive fallback ready user (FRU) .24
8 Test procedures .24
8.1 General .24
8.1.1 Purpose .24
8.1.2 Driving environment .24
8.1.3 System settings and test driver roles . 25
8.1.4 Common test pass criteria . 25
8.1.5 Confirmation of the human machine interface (HMI) design . 25
8.1.6 Success rate and number of trials . 25
8.1.7 List of test scenarios . 25
8.1.8 Test sites . 26
8.2 Scenario 1: Reaction to unresponsive fallback-ready user . 26
8.2.1 Test scenario . 26
8.2.2 Pass criteria . 26
8.3 Scenario 2: Direct disengagement by steering input .27
8.3.1 Test scenario .27
8.3.2 Pass criteria .27
8.4 Scenario 3: Continued operation after brake input .27
8.4.1 Test scenario .27
8.4.2 Pass criteria .27
8.5 Scenario 4: Forward vehicle braking hard .27
8.5.1 Test scenario .27
8.5.2 Pass criteria . 28
8.6 Scenario 5: Aggressive cut-in from the adjacent lane . 28
8.6.1 Test scenario . 28
8.6.2 Pass criteria . 29
8.7 Scenario 6: Obstacle in lane . 29
8.7.1 Test scenario . 29
8.7.2 Pass criteria . 30
8.8 Scenario 8: Approaching geographical operational design domain (ODD) boundary . 30
8.8.1 Test scenario . 30
8.8.2 Pass criteria . 30
8.9 Scenario 9: Engagement restricted outside ODD . 30
8.9.1 Test scenario . 30
8.9.2 Pass criteria . 30
Annex A (informative) MCS Type 2 description and design considerations .31
Bibliography .38
PROOF/ÉPREUVE
iv
ISO 23792-1:2026(en)
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.
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 patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems.
This first edition cancels and the first edition of ISO/TS 23792-1:2023, which has been technically revised.
The main changes are as follows:
— addition of Type 2 systems (5.4) and requirements associated with Type 2 systems;
— addition of requirements associated with misuse countermeasures (6.5);
— addition of Type 2 system description and design considerations (Annex A).
A list of all parts in the ISO 23792 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.
PROOF/ÉPREUVE
v
ISO 23792-1:2026(en)
Introduction
An automated driving system (ADS) needs to be designed with the capability to cope with various conditions,
such as the driving environment, behaviour of other vehicles in the surroundings, traffic regulations, etc.
In addition, an ADS designed to operate on motorways can encounter various situations such as merging
into the main lane of traffic, adjusting the speed according to congested or freely flowing traffic, overtaking
other vehicles, or changing lanes when approaching an exit or lane closure.
For Level 3 automated driving, the ADS issues a request to the fallback-ready user (FRU) to take over driving
tasks when it cannot respond to certain conditions or situations.
The ISO 23792 series identifies the performance requirements for an ADS based on its capability to respond
to certain conditions and situations. The requirements are derived in order to reliably transfer the control
between the human driver and ADS, and for safe operation by the ADS.
The ISO 23792 series focuses on the system functionalities, under the assumption that the FRU is available
and responsive to system requests to take over driving tasks.
PROOF/ÉPREUVE
vi
International Standard ISO 23792-1:2026(en)
Intelligent transport systems — Motorway chauffeur systems
(MCS) —
Part 1:
Framework and general requirements
1 Scope
[5]
Motorway chauffeur systems (MCS) perform Level 3 automated driving on limited access motorways with
[5]
the presence of a fallback-ready user (FRU) .
This document describes a framework of MCS including system characteristics, system states and transition
conditions and system functions.
This document specifies requirements for the basic set of functionalities of a MCS, and test procedures to
verify these requirements.
[5]
The requirements include vehicle operation to perform the entire dynamic driving task (DDT) within the
[5]
current lane of travel, to issue a request to intervene (RTI) before disengaging, and to extend operation
and temporarily continue to perform the DDT after issuing an RTI.
Requirements and test procedures for additional functionalities (such as lane changing) are provided in
other parts of the ISO 23792 series.
Means related to setting a destination and selecting a route to reach the destination are not within the scope
[11]
of this document. This document applies to MCS installed in light vehicles .
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 15622, Intelligent transport systems — Adaptive cruise control systems — Performance requirements and
test procedures
ISO 21448, Road vehicles — Safety of the intended functionality
ISO/SAE PAS 22736, Taxonomy and definitions for terms related to driving automation systems for on-road
motor vehicles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/SAE PAS 22736 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/
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
3.1
subject vehicle
SV
vehicle equipped with a motorway chauffeur system (MCS) feature
3.2
motorway
road specially designed and built for motorized traffic that does not serve properties bordering on it, and
does not cross at level with any road, railway or tramway track, or footpath
Note 1 to entry: Specific characteristics of motorways include the following;
— they provide, except at special points or temporarily, separate carriageways for the two directions of traffic,
separated from each other either by a dividing strip not intended for traffic or, exceptionally, by other means;
— they are specifically sign-posted as a motorway;
— they are prohibited for access from non-motorized road users, such as pedestrians and cyclists.
Note 2 to entry: Roads which satisfy the conditions listed in Note 1 to entry can be referred to using different terms in
different countries.
3.3
route
planned sequence of waypoints to reach a destination
Note 1 to entry: See Figure 1.
Key
1 route A
2 route B
3 route C
a
To destination.
Figure 1 — Route
3.4
path
combination of one or more neighbouring lanes in the same direction of travel along a given route
Note 1 to entry: See Figure 2.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
Key
1 path A
2 path B
Figure 2 — Path
3.5
trajectory
sequence of locations that define the intended motion vector of the subject vehicle (SV) used as references
for vehicle motion control
Note 1 to entry: The motion vector includes longitudinal position and/or speed, also lateral position and/or the
vehicle’s orientation information.
Note 2 to entry: See Figure 3.

a
Trajectory.
Figure 3 — Trajectory
3.6
vehicle motion control
VMC
activities necessary to adjust vehicle movement continuously in real time, including lateral control and
longitudinal control
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
Note 1 to entry: “Lateral vehicle motion control” and “longitudinal vehicle motion control” are defined in ISO/
SAE PAS 22736.
4 Abbreviated terms
ACC adaptive cruise control
[5]
ADS automated driving system
[5]
DDT dynamic driving task
[5]
FRU fallback-ready user
FV forward vehicle
HMI human machine interface
MCS motorway chauffeur system
[5]
MRC minimal risk condition
MRM minimal risk manoeuvre
[5]
ODD operational design domain
[5]
OEDR object and event detection and response
[5]
RTI request to intervene
SV subject vehicle
TTC time to collision
VMC vehicle motion control
V2X vehicle to everything (wireless communication)
5 Characteristics of motorway chauffeur systems (MCS)
5.1 General
This document covers a variety of implementations of MCS based on its operational design domain (ODD)
(see 5.2) and functionalities (see 5.3).
The ODD definition of an MCS is considered to be design-specific for its implementation. Therefore, the
requirements in this document apply to the functionalities and performance of the MCS within its prescribed
ODD.
5.2 Operational design domain (ODD)
5.2.1 General
Each MCS shall have a pre-defined ODD, and the user shall be informed of the general ODD limitations (i.e. to
make clear under which conditions a given MCS is capable of operating or not).
The description of an ODD shall, at minimum, include the following information unless the item does not
represent a restriction for system operation.
— Roadway physical characteristics.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
— Traffic in the surrounding environment.
— Abnormalities in roadway operational condition.
— Ambient environmental conditions.
Subclauses 5.2.2 to 5.2.5 provide examples of possible ways to describe the above-mentioned ODD attributes.
However, such attributes are not limited to those listed below, and more details should also be added as
needed. ISO 34503 provides a sample list of ODD attributes.
Figure 4 illustrates an image of the geographical ODD boundaries for an MCS capable of operating from the
entrance to the exit of a motorway.
Key
1 service area
2 junction
3 tollgate
4 exit
example of geographical ODD of MCS
An MCS may also be designed to operate within more restricted boundaries that do not include entrance and
exit ramps or merging and lane changing locations.
Figure 4 — Example of geographic boundary (geofence)
5.2.2 Roadway physical characteristics
Roadway characteristics should be considered as possible ODD attributes. An MCS may be designed to
operate on roads with or without certain characteristics such as those mentioned below.
— Road configuration (e.g. number of lanes in each direction, existence of medians, road shoulders).
— Road structure characteristics (e.g. curvatures, slopes, undulations).
— Quality and visibility of lane markings.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
— Surface characteristics of road structures (e.g. irregularity, running resistance friction coefficient,
potholes).
NOTE To explain the above general roadway characteristics as part of the ODD to the user, sections of the
motorway can be mentioned. For example, if the absence of a median strip to divide the carriageway is an out of
ODD condition, the starting point and the end point of the section with no median strips can be considered as the
geographical boundaries of the ODD.
5.2.3 Traffic in the surrounding environment
The existence of traffic in the surrounding environment and its motions (e.g. travelling speed, travelling
direction) may be considered as a possible ODD attribute. Vehicles in the forward direction, as well as in
the adjacent lanes and behind the subject vehicle (SV) may be considered as ODD attributes for an MCS to
operate.
The existence of emergency vehicles (e.g. ambulance) may also be considered as a possible ODD attribute.
If an MCS is not capable of responding appropriately to emergency vehicles, the existence of approaching
emergency vehicles should be considered as an out of ODD condition.
5.2.4 Abnormalities in roadway operational condition
Restrictions in roadway operational conditions, such as those in the following list, should be considered as
possible ODD attributes.
— Lane blockage.
— Traffic incident (e.g. crash, failed vehicle).
— Existence of road work (e.g. construction, maintenance).
5.2.5 Ambient environmental conditions
Characteristics related to ambient environmental conditions (including weather conditions), such as those
in the following list, should be considered as possible ODD attributes.
— Lighting conditions (e.g. illuminance, direction).
— Temperature.
— Rain, snow, hail (e.g. precipitation impact on visibility).
— Wind (e.g. speed, direction).
— Fog (e.g. visual distance).
NOTE Time of day can be used to explain the above ambient environmental conditions as ODD limitations, and
potentially other ODD limitations that are subject to regular changes during time of the day. For example, if illuminance
condition is an ODD limitation for the ADS designed to operate in areas without streetlamps, "night time" can be used
to express such ODD limitation.
5.3 System functionalities
5.3.1 General
Subclauses 5.3.2 and 5.3.3 define the functionalities of an MCS. Each MCS shall incorporate the basic set of
functionalities (5.3.2) and may also be equipped with additional functionalities (5.3.3). Each functionality
may have further detailed classifications associated with individual requirements.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
5.3.2 Basic functionalities to realize in-lane operation
The following items are the basic set of functionalities with which all MCS shall be equipped, including those
that only operate in a single lane.
— Perform the entire DDT within the current lane of travel. See Clause 7 for minimum performance
requirements of the DDT.
— Continuously monitor (at minimum, the driving environment, system conditions, vehicle conditions and
driver or FRU) if the required operating conditions are satisfied. See 6.2 for the requirements on the
changes in system states as the result of monitoring these items. See 6.3.2, 6.3.8, 6.3.9, and 6.3.10 for
requirements on the monitoring functions.
— Inform the driver or FRU of the MCS operating state and state changes. See 6.2 for requirements related
to state transitions, and 6.3.5 for status indication requirements.
— Issue an RTI when operating conditions are either detected or predicted to no longer be satisfied. See
6.3.4 for related requirements.
— While issuing an RTI, extend operation and continue to perform the DDT for a sufficient time for the FRU
to respond. See 6.4 for related requirements.
— If the FRU does not respond adequately to the RTI, bring the SV to a stop. See 7.5 for related requirements.
5.3.3 Lane changing functionalities
In addition to the basic set of functionalities, an MCS may be equipped with additional functionalities, for
example to perform a lane change during its operation. The ISO 23792 series classifies lane changes into two
categories: a discretionary lane change and a mandatory lane change.
The primary difference between discretionary and mandatory lane changes are the time-criticality to
perform a lane change, whereas a mandatory lane change becomes time-critical for trip continuation.
Examples of situations in which a mandatory lane change can be necessary include when the appropriate
lane must be selected to pass junctions, or the current lane of travel will end and so merging into another lane
is required. For a mandatory lane change, the lane change manoeuvre must be completed before reaching
a specific location. Requirements and test procedures to verify these requirements are to be specified in
1)
ISO 23792-3:—.
Examples of situations in which an MCS may perform a discretionary lane change include overtaking slower
traffic or selecting a lane to prepare for a future diverging or merging scenario. For a discretionary lane
change, an MCS may delay the manoeuvre until the conditions for initiating the lane change are satisfied or
cancel the lane change when conditions are not satisfied. Requirements and test procedures to verify these
2)
requirements are to be specified in ISO 23792-2:—.
An MCS may be equipped with additional functionalities other than lane changes. However, these are not
defined in the ISO 23792 series.
5.4 Classification
An MCS can be further classified into the following two categories based on their relationship with other
driving automation features with which the subject vehicle is equipped.
— Type 1 MCS is engaged independently from other driving automation features, directly following an
explicit driver command through a dedicated procedure.
— Type 2 MCS is integrated with other driving automation features that operate at different levels of
automation. Type 2 MCS engages by automatically transitioning from another lower-level driving
1) Under preparation. Stage at the time of publication: ISO/PWI 23792-3:2026.
2) Under preparation. Stage at the time of publication: ISO/FDIS 23792-2:2026.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
automation feature without a dedicated driver command (see Annex A). Such a system containing
multiple driving automation features with automatic transitioning capability is described as a “multi-
feature system” in this document.
5.5 System limitations
Situations with performance-impairing effects (see 6.4.2.5) and incapacitating effects (see 6.4.2.6) and their
possible consequences should be documented.
5.6 Providing information to the user
Providers of an MCS are expected to provide the user with the necessary information regarding its usage
prior to the first actual usage of the MCS, for example by actively explaining the intended usage and roles of
the FRU to the user and including the information in the owner’s manual. Information provided in 5.2 to 5.5
should be considered as the basis of the information.
NOTE The provider of an MCS under a typical private vehicle purchase or lease arrangement is the vehicle
manufacturer or dealer, but when a vehicle is rented or borrowed, the provider is the vehicle owner or car rental
company, who can also use the means described in A.4.3.
EXAMPLE If the SV is equipped with multiple driving automation features, special care needs to be taken in order
to explain the difference in the user’s role while MCS is engaged, compared to when any other driving automation
feature of Level 2 and below is engaged.
6 General system requirements
6.1 Operating conditions
6.1.1 General
Subclauses 6.1.2 to 6.1.4 describe the basic principles of MCS engagement and disengagement. These
principles serve the purpose of highlighting the specifics for a Level 3 ADS compared to other levels of
automation, especially considering the interaction with the driver or FRU.
6.1.2 Engagement conditions
The MCS shall engage to perform the entire DDT within its prescribed ODD only when minimum performance
requirements of the DDT during normal operation specified in 7.4 can be satisfied. The MCS shall have a
predefined set of engagement conditions specified in the overall system design. See 6.2.3.2 for details.
6.1.3 Disengagement-triggering conditions
The MCS shall continue to operate for a sufficient time for the FRU to respond (see 6.2.5) before disengaging,
unless specific direct disengagement conditions described in 6.1.4 are satisfied. For this reason, the MCS
shall have a predefined set of disengagement-triggering conditions specified in the overall system design
(see 6.2.4.3), which occur within the prescribed ODD to notify the FRU of a need to disengage. The MCS
should avoid trip continuation and unnecessary acceleration after detecting a disengagement-triggering
condition.
Refer to 6.4 for detailed requirements related to continuation of MCS operation after encountering
disengagement-triggering conditions.
6.1.4 Direct disengagement conditions
The MCS shall be designed to disengage in such a way that the risk of relinquishing control of the SV in active
traffic, without confirming that the FRU has taken over the control (i.e. becoming a driver to perform the
DDT) is minimized. See 6.3.7 for system reaction to driver FRU input.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
6.2 State transition
6.2.1 General
The MCS shall operate based on the system states and transition conditions specified in 6.2.2 to 6.2.5.
Figure 5 shows the fundamental system state transition diagram for an MCS. The following subclauses
define the system condition of each state as well as the transition conditions when the system state changes.
Sub-states may be added as needed. In general, all of the system states and transitions described in Figure 5
shall be indicated to the user (see 6.3.5 for requirements).
Key
A off state
B standby state
C requesting fallback state
D MRM
E nominal operation state
F MCS does not perform the DDT (i.e. MCS is disengaged, user is expected to be a driver)
G MCS performs the DDT (i.e. MCS is engaged, user is expected to be a FRU)
1 MCS turned on
2 engagement conditions are satisfied
3 FRU initiated transfer of control from MCS to FRU
4 disengagement triggering condition detected
5 MCS requested and FRU responded transfer of control from MCS to FRU
6 MCS turned off
7 MCS turned off
8 MCS turned off
Figure 5 — State transition diagram
6.2.2 Off state
6.2.2.1 State definition
In the off state, the MCS is turned off. Therefore, the VMC function (see 6.3.3) shall be inactive. Monitoring
functions (e.g. localization as described in 6.3.11) may be active in order to detect conditions that influence
transitions.
PROOF/ÉPREUVE
ISO 23792-1:2026(en)
6.2.2.2 Transition 1 (from off state to standby state)
6.2.2.2.1 General requirements
At least the following conditions shall be satisfied for the MCS to transition from its off state to the standby
state (key element 1 of Figure 5).
— Absence of performance-impairing situations (see 6.4.2.5).
— Powertrain of the SV is activated.
— SV is approaching or detected to be on a motorway (see 6.3.11).
6.2.2.2.2 Type 2 specific requirement
The multi-feature system, including MCS, is turned on.
6.2.3 Standby state
6.2.3.1 State definition
In the standby state, the MCS shall determine if engagement conditions are satisfied by continuously
monitoring, at a minimum, the conditions of the driving environment (see 6.3.2), system (see 6.3.10) and SV
(6.3.8).
6.2.3.2 Transition 2 (from standby state to nominal operation state)
6.2.3.2.1 General requirements
The MCS shall transition from the standby state to the nominal operation state (key element 2 of Figure 5)
when engagement conditions are satisfied. Engagement conditions shall, at minimum, include all of the
following conditions.
— The driving environment satisfies the ODD.
— FRU is present within the designated driver’s seat (see 6.3.8).
— The current speed of travel is within the op
...