Comment by georgeecollins

I took a class in cognitive design (fancy name for controls design) with Donald Norman (he wrote Design of Everyday things) and his standard assignment was to ask us to make the controls for a clock radio television. This was a long time ago. One of the points of the exercise was to make us realize that combining different devices and their controls didn't always make sense. In the same sense in a car their is a lot to be gained by keeping the controls for audio and the controls for temperature separate. The only good reason is to save money on buttons and knobs.