Effects of one-pedal automobile operation on the driver's emotional state and cognitive workload.

A one-pedal system for operating an electric vehicle allows drivers to flexibly accelerate and decelerate (and even stop) by using just an accelerator pedal. Based on previous findings, one-pedal operation is considered to have the potential to increase positive emotions and decrease cognitive workload. To test this possibility, the present study compared the emotional state and cognitive workload between one-pedal and conventional two-pedal operation. Participants drove a vehicle on public roads, and driving enjoyment (i.e., pleasure and immersion) and the cognitive workload (i.e., ease and effortlessness) were assessed by means of questionnaires. In addition, physiological variations associated with driving pleasure and difficulty were assessed by electroencephalography (EEG). Both the questionnaire and EEG results revealed an increase in driving enjoyment in one-pedal operation. On the other hand, only the EEG results suggested a decrease in the cognitive workload in one-pedal operation; the questionnaire results did not show a significant difference between the pedal conditions. These findings support the notion that one-pedal operation has a positive influence on the driver's mental state, though its influence on the cognitive workload will require further investigation. We discuss future directions toward a better understanding of the effects of one-pedal operation on the driver's mental state.