Other than driving (the primary task), operations like controlling the air conditioner, the audio system, the inner lights, the navigation etc. will highly affect the experience in a vehicle as well. Sometimes, the secondary task might also disturb the primary task and lead to a security concern.

• Buttons or/and Knobs: Complex display, confusing, visual distraction
• Touch Screen: Visual distraction, high cognitive load
• Voice Control: Low accuracy without large-data server, annoying, interference

• Natural – operations are consistent with results we want
• Low cognitive load – require minimal visual and aural resource
• Independent – Passenger and driver can separately operate

• Sensitive – may mistake the unconscious movement as operation
• Interference – detection might be interfered by background and shadow
• Diverse preference – meaning of gesture are diverse among users

• One button – we choose to minimize the number of button, instead of removing all. Just one button to activate the whole system.
• 3D camera – to have a best detection of gesture.
• Optimal preference – we conduct an academic study to understand the preference among users.