ISO/PAS 23735:2025
(Main)Road vehicles — Ergonomic design guidance for external visual communication from automated vehicles to other road users
Road vehicles — Ergonomic design guidance for external visual communication from automated vehicles to other road users
The scope of this document encompasses design parameters of external visual communication used by single mode L4/L5 automated driving system-dedicated vehicles (ADS-DVs), as defined in SAE J3016. Guidance is given for passenger cars (including sport utility vehicles and light trucks) and commercial vehicles (including heavy trucks and buses), as well as derivatives of them that carry or do not carry compartments for occupants (i.e. driver or passengers). These vehicles can be operated in different domains, covering several alternative scenarios and use cases (e.g. open roads, motorways, urban environments, confined areas, geo-fenced areas with dedicated lanes, ports, terminals, pits). It is assumed that the design of ADS-DVs will be unique, thus making it readily apparent that the vehicle is an ADS-DV (see also Annex A for descriptions of use cases concerning the need for communication). The wide range of domains makes it important to consider users with different experiences and abilities, e.g. experienced and inexperienced drivers, elderly, people with disabilities and children.
Véhicules routiers — Lignes directrices de conception ergonomique de la communication visuelle extérieure du véhicule automatisé aux autres utilisateurs de la route
General Information
Standards Content (Sample)
Publicly
Available
Specification
ISO/PAS 23735
First edition
Road vehicles — Ergonomic design
2025-03
guidance for external visual
communication from automated
vehicles to other road users
Véhicules routiers — Lignes directrices de conception
ergonomique de la communication visuelle extérieure du véhicule
automatisé aux autres utilisateurs de la route
Reference number
© ISO 2025
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Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Historical perspective on the interaction between road users . 4
4.1 General .4
4.2 Road sharing .4
4.3 History of external communication systems .5
5 Current and future challenges in road user interaction . 6
6 Framework for interaction . 7
6.1 General .7
6.2 Encounter, interaction and conflict . .7
7 Communication channels . 8
7.1 General .8
7.2 Communication as a negotiation .8
7.3 Considerations for implicit signalling .8
7.4 Integration of implicit and explicit signals .9
8 Expectation of other road users .10
8.1 General .10
8.2 Acceptance/acceptability of new technology .10
8.3 Expectations for perception, comprehension and behaviour .11
8.3.1 Expected influence on road users’ perception .11
8.3.2 Expected understanding upon exposure .11
8.3.3 Expected influence on road users’ behaviour .11
8.4 Cultural and regional considerations . 13
8.5 Demographic factors . 13
8.5.1 General . 13
8.5.2 Age . . . 13
8.5.3 Gender . 15
8.5.4 Disabilities . 15
9 Developing a communication language .16
9.1 General .16
9.2 General communication needs .17
9.3 Communication protocols .17
9.4 Content selection, media allocation, realization and coordination .18
9.5 External communication language considerations .18
10 Re gulatory and standards considerations .20
11 Implementation guidance .21
11.1 General .21
11.2 Message content .21
11.2.1 Coordination with vehicle motion .21
11.2.2 Learnability .21
11.2.3 Addressability . 22
11.3 Visual attributes . 22
11.3.1 General . 22
11.3.2 Presentation style . 22
11.3.3 Location . 22
11.3.4 Angle of view . . 23
11.3.5 Colour . 23
iii
11.3.6 Brightness .24
11.4 Integration with existing systems .24
11.4.1 Coordination and choreography with other signals .24
11.4.2 Discussion on integration with automated driving system .24
11.5 E valuation .24
Annex A (informative) Use cases in traffic situations with need of communication .25
Annex B (informative) Description of the multiple resource theory .48
Bibliography .50
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Foreword
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