Scubaregs said:
Don't understand this safety bit of the touchscreen argument. If using the idrive controller you still have one hand off the wheel and you still need to be looking at the screen to navigate to where you wish to be. It is no safer using the idrive controller than touching the screen.
Massive difference in human resources management.
Your eyes operate as one entity (unless you are certain types of amphibians)..so both eyes need and can only look in one place.
If you are looking at a screen you are not looking at the road.
Human brain uses about 80% of its available capacity to receive, process and initiate actions based on seeing things.
If you have a HUD then its better but even so your focus has to move from the far to the foreground to resolve the information.
With a touchscreen your eyes need to look at the screen, follow /direct your finger to the landing point, confirm the action and view the result.
Lack of tactile / other sensory clues further impair /overload the precious visual resource. The famous ' what the f&*k is it doing now'
With a mechanical knob, your arm/hand/fingers move, using a lower priority, less resource intensive, autonomous part of your brain.
That's why you can press a brake, turn the steering wheel, press the accelerator, operate a stalk all at the same time..
If that was a touch screen system you could only do one at any one time.
Also limbs/fingers acquire 'muscle memory' with the relevant part of the brain. So an action does not need conscious thought as proved by steering /braking etc.
So over a period of time if you use the idrive enough you learn to use all the 6 buttons as well reducing the interface time.
The tactile feedback from a physical device like a know or switch all helps that process.
All that reduces workload and leaves more resources available for the important bit, looking out of the windscreen!