During my internship at a company in the automotive industry I was allowed to create my own human machine interface for an automated vehicle. The only condition was that it had to be completely based on touch.
My approach was to create a system that had two touch displays beside the steering wheel and on center stack behind the steering wheel. That way it was almost possible to interact with the system without taking your hands of the steering wheel.
During user tests it was interesting to investigate that young people understood the logic behind the system immediately but elderly people seemed to need some more time to get it. After doing multiple loops with one paper prototype and a low fidelity touch prototype a final design was made and the system was coded later.