  Although the automotive industry has been among the sectors that
best-understands the importance of drivers' affect, the focus of design and
research in the automotive field has long emphasized the visceral aspects of
exterior and interior design. With the adoption of Advanced Driver Assistance
Systems (ADAS), endowing 'semi-autonomy' to the vehicles, however, the scope of
affective design should be expanded to include the behavioural aspects of the
vehicle. In such a 'shared-control' system wherein the vehicle can intervene in
the human driver's operations, a certain degree of 'intrusive feelings' are
unavoidable. For example, when the Lane Keeping Assistance System (LKAS), one
of the most popular examples of ADAS, operates the steering wheel in a
dangerous situation, the driver may feel interrupted or surprised because of
the abrupt torque generated by LKAS. This kind of unpleasant experience can
lead to prolonged negative feelings such as irritation, anxiety, and distrust
of the system. Therefore, there are increasing needs of investigating the
driver's affective responses towards the vehicle's dynamic behaviour. In this
study, four types of intrusive feelings caused by LKAS were identified to be
proposed as a quantitative performance indicator in designing the affectively
satisfactory behaviour of LKAS. A metric as well as a statistical data analysis
method to quantitatively measure the intrusive feelings through the vehicle
sensor log data.
