Publication

The purpose of the study was to investigate how the "driving behaviour" characteristics of AV cars affect users' understanding, trust and acceptance of AD in different situations. An experimental study was conducted on the AstaZero test course where 18 participants experienced two consecutive AV-test runs with two different driving behaviours – ‘Defensive’ and ‘Aggressive’. The vehicle had a Wizard of Ozsetup, meaning that it was controlled by a (to the participant) hidden test driver. Each test run included nine situations of which seven were considered as possibly ‘critical’ traffic situations from a user trust perspective. Data on users’ trust in and experience of AV was collected by means of different questionnaires, an adapted UX curve, and personal interviews. The results show that he driving behaviour of an AV affects users´ trust in the AV. The ‘Defensive’ driving behaviour was in general rated highest regarding perceived trust as predictability was perceived as higher since it more clearly showed its intentions. The ‘Aggressive’ driving behaviour was however in some situations assessed as the more effective but in other situations as unpredictable. The results demonstrate the importance of considering the vehicle as a whole when designing the HMI.