Making Passenger Conversation in Partial Driving Automation: Effects of Relationship Between Driver and Passenger on Driver Fatigue and Driving Performance

Abstract

Driving automation leads drivers to be disengaged by dynamic driving tasks, but the need for the driver to monitor traffic environment is existed in a partial automation. Monotonous road situations can produce drowsiness, resulting in poor driving performance. Conversation in automated vehicles is expected to mitigate fatigued driving. However, few studies have examined effects of conversation. This paper reports a driving simulator study describing impacts of passenger conversation on driver fatigue and driving performance regarding the relationship between a driver and a passenger. Participants were categorized into two groups: a passenger’s friends (ConvR) and people who had not met the passenger before (ConvNR) to examine whether the acquaintance with the passenger affects driver behaviour, driving performance, fatigue and workload. The results showed that drivers in ConvNR felt lesser sleepy and found it easier to drive than the drivers in ConvR, but no difference of driver behaviour and driving performance was observed between two groups. In addition, regardless of the relationship, making casual conversation led decreased fatigue and workload in comparison with solo driving without conversation. The practical implication for further conversation methods to regard driver fatigue and driving performance in the automated vehicle is discussed.