The effects of type of road and driver personality on drivers’ automation use: an on the road study with Tesla’s autopilot

Abstract: Research has shown that drivers are willing to use vehicle automation. However, automated systems can only be beneficial if they are accepted, trusted and used appropriately by the driver. Therefore, the present study investigates drivers' willingness to use vehicle automation as a function of driving situation characteristics and driver personality in an on-road experiment. Firstly, the study investigates whether drivers are more or less likely to use vehicle automation depending on the type of road (rural road or motorway). It will also test whether the type of road affects the driver's in-situ assessment of the automation (e.g., criticality and mental load). Secondly, it examines whether driver personality (Big Five and affinity for technology) is related to the rate of handover, and whether drivers' in-situ assessment of vehicle automation is correlated with the rate of handover.Thirty-eight participants completed a one-hour drive with six measurement intervals and a length of 24 km in the north of Berlin. In general, the results showed that a combined handover of lateral and longitudinal automation was used most frequently, regardless of the type of road. More specifically, the type of road influenced the drivers' handover behavior. Handovers to lateral and longitudinal automation were more likely on motorways than on rural roads. The type of road also influenced in-situ ratings of automation trust, usefulness and appropriateness. Drivers' personality was found to have a significant influence on their handover behavior. Lower neuroticism scores and higher affinity for technology were associated with higher proportions of handovers. The results also show that in-situ ratings correlate with usage behavior. Critical ratings were negatively related to handovers, whereas trust, appropriateness and usefulness were positively related to handovers.Based on the results, we conclude that drivers will use automated driving functions when they have the opportunity to do so. Their usage behavior is influenced by the type of road, their assessment of the situation and aspects of their personality. The study serves as a starting point for future studies, such as naturalistic driving studies. The results also help in the design of vehicle automation and increase the understanding of drivers' use of vehicle automation.

Keywords: automated driving, driver behavior, human-automation interaction, driver-initiated handovers, on-road study

DOI: 10.54941/ahfe1004279

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