BRAVE population survey on the acceptance of and trust in conditionally automated cars

In BRAVE’s work package 2 “Multidisciplinary study and specification of user’s and stakeholder’s requirements” the opinions of different road users groups – especially of the vulnerable road users (VRU) pedestrians, cyclists and motorcyclists – about conditionally automated cars (CACs) where explored by a population survey of road users that was conducted in the EU member states France, Germany, Slovenia, Spain and Sweden as well as in Australia and in the USA. The online survey was carried out from December 2019 to February 2020. In each of the seven countries participating in BRAVE, almost 1,000 respondents answered the questionnaire.

The findings on the general a priori acceptance of CACs indicate a rather positive attitude of the respondents. With a relative majority, the respondents expect CACs to increase road safety as well as to be useful, easy to use and easy to communicate with. Nevertheless, a certain scepticism of the respondents can be detected when assessing the own intention to use such a car or the future interaction of the road users with CACs on the roads.

The general trust in CACs is also rated as rather positive by the road users surveyed. Almost half of the respondents express that CACs will be dependable, will act reliably and that they will overall trust in CACs. The level of general trust in CACs differs between the gender of the respondents, their age, their country of residence and their main transportation mode.

A special focus of this study is on the acceptance of and trust in CACs from the perspective of the certain road user groups. To depict them, a fictitious interaction with a CAC in road traffic was described in the questionnaire that was specifically adapted to each road user group. In such a situation, respondents state that they would feel mostly neutral or safe. However, noticeable differences between the road user groups can be identified, with car drivers and pedestrians perceiving their subjective feelings as less safe than two-wheelers on a bike or a motorcycle.

Out of eleven listed benefits, the four most expected benefits of CACs relate to safer driving behaviour: sufficient distances to other road users, better emergency braking reaction times, stricter adherence to traffic rules and more predictable driving. Two-wheelers, whether on bicycles or motorcycles, more than pedestrians and car drivers expect the introduction of CACs to have an increased positive impact on themselves as road users. Males emphasise expected benefits of CACs more strongly than females.

The three concerns most strongly stressed are those relating to the reliable functionality of the CAC including the possibility of system failures, hacker attacks or the take-over situation of a CAC. The unresolved question of liability in the case of a crash and the technical ability to detect the behaviour of other road users are emphasised as further possible problems. Pedestrians and car drivers are often more strongly concerned than cyclists and PTW-riders. In addition, it is females who express concerns more strongly than males.

An ethical dimension of the introduction of CACs becomes apparent in the need to program the behaviour of the CAC in the case of an unavoidable crash. In the assessment of the ethical principles guiding the programming of the CAC, an inconsistency becomes observable: a vast majority of the respondents agree with an (utilitarian) approach which states that in the event of a crash the automated car should behave to minimize the overall number of fatalities. At the same time, most respondents prefer to sit in a car that protects the passengers against all other road users.

In its characteristic as a cross-sectional study, the BRAVE population survey can be used as a starting point for a future regular monitoring of the attitudes of the population of EU member states towards highly automated or autonomous driving. A detailed presentation and discussion of the findings of the BRAVE population survey can be found in Deliverable 2.3 “Report on the findings of the population survey”, which can be downloaded from


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