Predicting Acceptability of Connected Automated Vehicles

Connected Automated Vehicles (CAV) are completely self-driving cars that are equipped with tools to communicate and share data with other devices both inside and outside the car, such as other cars, and public transport systems. The driver has the role of a passenger inside CAV. CAV is not available on the market right now, but they may dominate the road environment in the future. Many car manufacturers have already incorporated some degrees of automation into their cars, such as parking assist, and adaptive cruise control. Some manufacturers are now pilot testing vehicles with high or full automation in designated areas.

CAV may play an important role to solve several societal problems, such as increasing traffic safety, reducing traffic jams, enhancing mobility for those unable to drive, and reducing traffic CO2 emissions.

SUaaVE Project

In the SUaaVE project (Horizons 2020 project funded by the EU) we examine the acceptability and acceptance of CAV. Acceptability is an attitude people have towards CAV before they have experienced it. Acceptance is related to if people want to use or buy CAV after they have experienced it. We want to find out what drives the acceptability and acceptance of CAV, and what we can do to increase acceptability and acceptance for both potential users, as well as for other road users. SUaaVE aims to make a change in the current situation of public acceptance of CAV by focusing on the human side to improve more “intangible” aspects as safety perception, attitudes, and in general, emotional appraisal of CAV. First, we have examined what factors predict the acceptability of CAV. Based on an extensive literature review and several focus groups conducted in Italy, Spain, France, and the Netherlands, we proposed a psychological model that can predict acceptability of CAV.

Large Scale Survey in 6 European Countries

To test our psychological model that predicts the acceptability of CAV, we conducted a large scale survey. The survey was conducted online in 6 European countries: the United Kingdom, the Netherlands, Germany, France, Spain, and Italy. In total, almost 3800 people filled out the survey in April 2020. The sample was relatively evenly spread in terms of age (about 20% was between 18 and 30 years old, and about 20% was older than 55), gender, and country (about 630 participants per country). In the survey we explained what CAV is, and measured acceptability, how they perceived different aspects of CAV, and also measured various individual differences such as interest in technology and personal values.

Predicting Acceptability of CAV

We found that acceptability of CAV is predicted by its attributes, the perceived adoption norm, and the perceived behavioral control. The perceived adoption norm is the extent to which someone believes close others (such as friends, family, and coworkers) will adopt CAV in the future. The perceived behavioral control is the extent to which someone believes they will be capable of using CAV. Both of these positively predicted acceptability of CAV. As for CAV’s attributes, we found 7 distinct characteristics of CAV that influence acceptability: perceived safety (is CAV safe?), perceived convenience (is CAV useful?), perceived control (can I control CAV’s behavior?), perceived pleasure (is driving CAV enjoyable?), trust in CAV technology (is CAV’s computer system trustworthy?), perceived environmental sustainability (is CAV environmentally friendly?), and perceived status-enhancement (is CAV a status product?). Out of these, perceived safety, perceived convenience, and perceived environmental sustainability had the strongest positive effects on acceptability of CAV. Based on these results, we formulated some initial guidelines to enhance public acceptability.

More Information

Aside from the direct predictors of acceptability, we have examined other factors that could influence acceptability of CAV. For example, we have examined differences between drivers and non-drivers, and effects of personal values, the need for control, and experience with car technology. The full results are available as open access on On this website you can read more about the SUaaVE project in general, as well as read all currently published open access deliverables.


Internal factors that influence the passenger’s state in automated vehicles

There are factors concerning the trip and the driver that are crucial when describing the emotional and cognitive state of the passenger. This can be divided into two categories: Profile-passenger factors and trip-passenger factors.


The characteristics of the passenger could affect their perception of the driving experience. As a first approach, the category “Profile-Passenger factors” includes these factors:

  • Gender.
  • Age.
  • Origin.
  • Culture.
  • Experience in driving.
  • Driving predisposition.
  • Personality.
  • Past experiences.
  • Physical and cognitive characteristics.


In addition to the elements that constitute the environment of the trip, there are some trip characteristics that are also of great relevance for the cognitive and emotional description of the passenger. Those characteristics are the ones related with the link between the passenger and the trajectory. These can be classified as follows:

  • Time to complete the trip: From ample time, to very short time, to irrelevant.
  • Importance of get in time: From very important, to irrelevant.
  • Purpose of the trip: Work, hospitalization, holidays, etc.
  • Pre-journey and post-journey activity.
  • Familiarity with the trip // with the environment: prompt, regular // very familiar, completely new.

As an example of the previous factors, the driving experience and how the passenger perceives it, can be crucially different according to the purpose of its trip. For instance, if the purpose of the trip is holidays, the dense traffic could not get on his/her nerves in the same way, as if the trip is to get to work being short in time.

During the development of the emotional and cognitive models in SUaaVE, these factors will be identified and defined according with their relevance regarding the passenger’s state. For more information about other factors that can influence the passenger’s state, please see Deliverable 3.1. Framework of the emphatic module and preliminary relationship among automotive factors with cognitive and emotional passenger state.


Special Session of SUaaVE at CHIRA 20 Conference

The Special Session on “Reliable Estimation of Passenger Emotional State in Autonomous Vehicles (SUaaVE 2020)” was held online November 6th at the International Conference on Computer-Human Interaction Research and Applications 2020 (CHIRA).

In this session, Lucie Lévêque (from Université Gustave Eiffel -IFSTTAR in the past-, one of the SUaaVE’s partners) presented the paper “Development of an Immersive Simulation Platform to Study Interactions between Automated Vehicles and Pedestrians”. The paper focuses on a novel simulation platform, the V-HCD, allowing the conduct of immersive experimentations, both from the pedestrian’s and the driver’s point of view. This platform will be used to study the acceptance of the automated vehicle in SUaaVE, and further to support the human-centred design of a future empathic automated vehicle (AV).

Figure 1: Example of scenario implemented on the V-HCD platform to study the interaction between a pedestrian and an AV with a more or less attentive driver. Université Gustave Eiffel ©.

Juan Felipe Medina-Lee (from the Center for Automation and Robotics, researcher in the project ‘Programmable systems for intelligence in automobiles’ as a member of Autopia program) presented “Traded Control Architecture for Automated Vehicles Enabled by the Scene Complexity Estimation”. The research consists on a novel traded control architecture proposed to enhance the operational domain of the autonomous driving system (ADS) under the premise that vehicles and humans may need to adapt their cooperation level depending on the context.

The third presentation was conducted by Juan-Manuel Belda-Lois (researcher at Instituto de Biomcecánica de Valencia, IBV, the coordinator partner of the SUaaVE project) with the title “The Estimation of Occupants’ Emotions in Connected and Automated Vehicles”. This research covers an initial experiment to identify changes in the emotional state of the occupants in different driving experiences (in a driving simulator and in real conditions) by measuring and analysing the physiological signals of the participants, serving as a basis for the generation of the emotional model. The results showed that it is possible to estimate the level of Arousal and Valence of the participants during the journey from the analysis of ECG, EMG and GSR signals.

Figure 2: HRV along the experiment and emotional components (Arousal and Valence) declared by a co-driver in each event of an urban journey by car. IBV ©.

The last presentation of the session was conducted by Davide Salanitri (from IDIADA, partner of the SUaaVE project) with the title “Evaluation of a New System in Future L4 Vehicles: Use Cases and Methodology for the SUaaVE European Project”. The paper describes the definition process of the use cases in SUaaVE, considering the different factors that characterize them.

Finally, in the session “Interaction Design” at CHIRA 2020, Benjamin Chateau (from CATIE, another SUaaVE’s partner) presented the paper “Exploring Empathetic and Cognitive Interfaces for Autonomous Vehicles”. An interface for automated vehicles capable of informing the user at any time about the road situation and reassuring him/her about the information processed by the vehicle.

Figure 3: Interface overview. CATIE ©.


Research accomplished in the framework of connected automated vehicles in the first year of SUaaVE project

SUaaVE is a H2020 project funded by the European Union aiming to enhance the public acceptance of highly connected automated vehicles (CAVs) by increasing trustworthiness via Human-Driven Design, including the participation of all road users as well as stakeholders. In April, SUaaVE has reached its first 12 months achieving relevant breakthroughs in its different research topics.

In the research about acceptance, a set of focus groups (led by RuG and conducted by CRF, IFSTTAR, VEDECOM and IBV) has been performed to identify the relevant psychological factors that influence the user acceptance in CAVs. A diversity of relevant road-users was involved aiming to make it representative (drivers, non-drivers, pedestrians, cyclists). These focus groups were carried out in different EU countries (Spain, Italy, and France) to analyse cultural differences. More than 50 people have participated in this research.

Furthermore, a large survey has been conducted in different countries (France, Germany, UK, Italy, Spain and The Netherlands), led by RuG, to analyse and verify the main factors that influence acceptance in CAVs, validating the results obtained in the focus groups. 3900 European citizens have participated in this survey.

Figure 1 . Countries that have participated in the large-scale survey in SUaaVE.

As regards to research in ethics, different interviews have been carried out by VEDECOM with experts in robotics, laws, human factors experts, sociologists and urban planners in order to analyse ethics in CAVs. In addition, it has been conducted focus groups with different road users (including people with disabilities) to identify their opinions and feelings reflecting their perceptions and attitudes, which may constitute drivers or barriers to the acceptance of CAV for ethical concerns.

Concerning the research to understand the passenger’s emotional and cognitive state during the trip, IBV has developed the Emotional Model composed by a Categorical Model (based on the analysis of contextual factors that influence the trip experience on board) and a Dimensional Model (the estimation of the emotional state of the passenger based on the parameters arousal and valence obtained from physiological signals from the passengers in the vehicle). Furthermore, BORDEAUX INP has designed a Cognitive Model to determine the cognitive states of the user in any situation in real time, with a significant impact on the user experience of the vehicle. Finally, TUM is working on the Observation Model, aimed to anticipate the passenger state. It will emulate the input-output dynamic map from external stimuli (road conditions, driving behavior), to resulting human emotional and cognitive state.

Figure 2 . Scheme of the different developments in SUaaVE to understand the passenger’s state.

Regarding the control strategies tackled in SUaaVE for the management of CAV behaviour to enhance trip user experience on-board, Bordeaux INP has designed a first interface prototype of a smart cognitive assistant aiming to provide the user with information on the traffic situation, the car’s behaviour, and the way it adapts to the passenger. Furthermore, IDIADA has developed a set of models for ambient comfort in the framework of CAVs, covering thermal comfort, acoustic comfort, visual comfort and postural comfort. Additionally, IDIADA has made great progress in motion comfort research, aiming to study the relationship between the passenger perception of the dynamic comfort and the way that the autonomous driving algorithms plans and executes a vehicle trajectory.

Figure 3 . Interface prototype of a smart cognitive assistant that informs the passenger about the main information processed by an automated vehicle. © Tous droits réservés/All rights reserved – Benjamin CHATEAU – CATIE – SUaaVE project – 2020.

At this stage of the project, CIVITEC has released the first version of the Immersive Virtual Human Centred Design (V-HCD) platform, a 3D virtual simulation environment for urban and highway road context. This platform will be used to adjust and validate the different developments in SUaaVE in the first loop of tests with subjects (to be carried out from April to October 2020). In this regard, IDIADA has led, with the participation of the rest of partners involved, the definition of the different methodologies that will be used for the evaluations of all the aspects involved in the project, specially covering the assessment of acceptance of the different developments.

Figure 4 . IDIADA DiM 250 dynamic simulator. The simulator will be used in the first loop for testing with subjects motion comfort.

SUaaVE is coordinated by the Institute of Biomechanics of Valencia (IBV). The consortium of the project is composed by a combination of research institutions (RUG, VED, IFSTTAR, CRF, TUM, BORDEAUX INP and IBV) and industrial and market partners (IDIADA, CVT and FICOSA group represented by AAA) oriented to Social Science, Human Factors Engineering, and Technical Engineering.

SUaaVE is funded by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 814999.

For more information of the project, see Follow us on Twitter @SUaaVE_project


First Milestone of the project, reached: SUaaVE frameworks and ALFRED use cases defined.

The first months of SUaaVE have mainly consisted in the formulation of different requirements and frameworks for the developments and research activities to be carried out in the next stages of the project.

One of the partial results, already obtained and available on project website (, has been the identification of the main social psychological factors that influence the Connected and Autonomous Vehicles (CAV) acceptance.

The work carried out regarding the ethical, legal and social challenges of artificial intelligence, will be the basis for the focus groups on the public opinion in these areas. The ethical decision-making algorithms for automated systems have been also studied.

In order to monitor and interpret the passenger state based on the cognitive state and emotional response in next steps of the project, SUaaVE partners have defined the empathic module framework. In addition, we have outlined the observer tool, which will serve to anticipate the passenger state not only detecting their responses, but combining categorical and dimensional approach.

We have also obtained “a new smart and multimodal Human Machine Interface (HMI) and strategies to ensure the user acceptability of ALFRED” (defined as a concept to humanise the CAV actions, which will result from the project), based on the quality of comfort, interaction and information.

Another partial result has been the definition of the use cases and the events for the future evaluation of the ALFRED concept (also available on website). Two types of use cases have been established: Situational use cases (to elicit specific emotions and composed of a short scenario where only one event) and Trip use cases (composed by a long scenario where several events occur).

Finally, consortium has advanced with the requirements of the V-HCD simulation platform that will be used for immersive experiments with subjects during next months.

All the planned actions in this period have been executed, the project is making good progress and successful results are expected by the consortium, which is composed by the IBV as coordinator, the Spanish companies IDIADA Automotive Technology, FICOSA ADAS andADVANCED AUTOMOTIVE ANTENNA; the Centro Ricerche FIAT; the University of Groningen; the Fondation Partenarial MOV’EOTEC, the French Transport Institute IFSTTAR, the Polytechnic Institute of Bordeaux and CIVITEC SARL; and the Technical University of Munich .

This project has been funded by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 814999.

For more information of the project, see Follow us on Twitter @SUaaVE_project


4 new projects on the European Horizon of the autonomous driving

Under the Horizon 2020 Research and Innovation Programme, the European Commission has recently funded 4 new projects focused on driver behaviour and acceptance of connected, cooperative and automated transport: Drive2TheFuture, PAsCAL, SUaaVE, Trustonomy.

These projects share some common topics to investigate on such as the assessment of public acceptance of autonomous driving; the analysis of the driver behaviour under different scenarios; the human/machine interconnections, and last – but absolutely not least – the investigation of ethical and legal issues associated with drivers of autonomous vehicles.

Lila Gaitanidou, CERTH/HIT, Drive2theFuture project coordinator, stresses out that “User should be in the core of designing and deploying connected and autonomous vehicles (CAVs). And this is valid for all means of transportation. There are different user categories addressed, from drivers and passengers, to related stakeholders and vulnerable road users, their needs and wants varying accordingly. Drive2theFuture, through its 12 pilots undertaken in 8 European countries and a series of design, modelling, training, awareness and dissemination activities, aims at actively involving all users in the process, towards a successful deployment of CAVs in Europe”.

Guillaume Gronier, LIST, PAsCAL project coordinator, explains that “Our aims is to create a “Guide2Autonomy” that will improve the understanding of the implications of connected and automated vehicles (CAVs) on society, educate future drivers and passengers and help decision makers navigate the transition to new forms of personal mobility resulting from the deployment of Connected and Autonomous Vehicles. It will not only focus on the interaction of the “users” in or near CAV, but also assess the impact of connected transport on people’s well-being, quality of life, and equity by using a strongly interdisciplinary mix of innovative tools from both human science and technology, to capture the public’s acceptance and attitude, analyse and assess their concerns, model and simulate realistic scenarios for hand-on practices, and validate the research innovation in a number of trials in the real world.”

The Instituto de Biomecánica (IBV) is leading the European project SUaaVE (SUpporting acceptance of automated vehicle) with the objective to improve the response and sensitivity of the autonomous vehicle, making it more aware of the occupants, pedestrians and other drivers needs. José Solaz, director of innovation in Automotive of the IBV, ensures that in this way “we will achieve a greater acceptance of the autonomous vehicle by solving the existing gap between technology and the real needs of citizens.”

Stefano Bianchi, Softeco, TRUSTONOMY project coordinator, thinks that “Building acceptance and trust in autonomous mobility is one of the keys to the success and actual implementation of the autonomous and connected vehicles. And this is what our project will be working on for the next three years, proposing a complete framework for the evaluation of technical solutions that constitute Autonomous Driving Systems (ADS).”

Drive2TheFuture, PAsCAL, SUaaVE and Trustonomy are ready to work together in the next years for pushing forward the autonomous driving! Stay tuned!


IBV leads a European project that will “humanize” the autonomous vehicles

The connected and autonomous vehicle already exists, but it is not fully accepted by users. Despite its advantages in terms of distraction related accidents reduction or the inclusion of people who need door-to-door transport, there is a reluctance to incorporate them on a day-to-day basis.

Indeed, social problems related to public acceptance, user awareness and ethics have become priority concerns for manufacturers and public administrations.

To address this problem, the Instituto de Biomecánica (IBV) is leading the European project SUaaVE (SUpporting acceptance of automated vehicle), funded by the Horizon 2020 program. The main objective of SUaaVE is to improve the response and sensitivity of the autonomous vehicle, making it more aware of the occupants, pedestrians and other drivers needs.

José Solaz, director of innovation in Automotive of the IBV, ensures that in this way “we will achieve a greater acceptance of the autonomous vehicle by solving the existing gap between technology and the real needs of citizens.”

This will be possible through close collaboration between companies, universities and technology centers, through a design process, known as people-oriented design (HDD) that will take into account the end user of the vehicle.

SUaaVE will solve this gap by improving the synergies of the social sciences, human factors research and the automobile market. “Placing the person in the center of technological development and not vice versa is key. I order to achieve it, we will carry out a continuous process of evaluation, collaborative design and creation of prototypes that will be tested by the future users” says the director of Automotive Market Innovation.

Participation of users and experts

More than 4,000 users of autonomous vehicles (passengers, traditional and future drivers, as well as vulnerable users) and more than 100 experts and interested entities will participate in the process.

The ten partners that, together with the IBV as coordinator, form the consortium are the Spanish companies IDIADA Automotive Technology and FICOSA ADAS; the FIAT Research Center in Italy; the University of Groningen (Holland); the MOV’EOTEC PARTNERSHIP Foundation, the French Transport Institute IFSTTAR, the Polytechnic Institute of Bordeaux and CIVITEC SARL in France; and the Technical University of Munich (Germany).

This project has been funded by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 814999.


SUaaVE kick-off meeting

It was held at Instituto de Biomecánica (IBV) facilities in Valencia, and it was attended by all the partners and some of the linked third parties. During the first day, our Project Officer, Mr. Georgios Sarros, joined the meeting and gave us a useful overview of INEA’s expectations regarding the project and recommendations about the management of the project. And work package’s leaders presented the WP plans.

During the second day, we had an action plan development workshop, that allowed all partners be engaged in technical discussions for preparing next months’ work.

For the next three years we will work on enhancing public acceptance of highly automated CAVs by increasing trustworthiness.

We would like to grateful the Centre for the Development of Industrial Technology (CDTI) its help during the preparation of this amazing project.

SUaaVE project has received funding from the from the European Union’s Horizon 2020 research and innovation programme under grant agreement Nº 814999


IBV attended the Transport Coordinators Workshop at INEA

We hosted more than 40 representatives of 26 new #H2020transport projects at INEA today.
Exciting to end the week with so much positive energy and exchange of ideas! Welcome on board!