Spinny-dial-based input, with the dial located just behind the shifter (just in front of where the cupholders usually are), is the best input method developed for cars so far.
The forces the UI to be a flat list in terms of navigation (rather than a 2d-space-filling UX mess). And being a flat 1d list, it encourages the list be short, which means more submenus, which is good!
If menus are consistent, you can mostly control without taking your eyes off the road.
Apple CarPlay already works with this input method.
I have a BMW with chip shortage touch-screen delete, and I can confirm that CarPlay is a royal pain in the neck to operate with just a dial. I have a touch-screen part on order so I can do a retrofit. Just the dial is usually fine when driving, but when parked the keyboard interface is impossible to operate. Sometimes though, navigating CarPlay with the dial causes me to have to look at the screen more than I'd have to with a touch-screen, since the dial is rather unpredictable (trying to get it over to the dock on the left is far from intuitive).
This is how Mazda handles the screen. The knob has a satisfying tick on rotation and rebound when pressed. The car's a little older now and the screen os is a bit slow, but usually keeps up with input. Radio and navigation have hard button shortcuts. It's just a good system.
i think this is subjective, i drove my moms car with this setup (mazda suv) to NY last weekend. I would NEVER buy a car like this. Touch screen for apple carplay is in my opinion the obvious best setup and the most intuitive interface. You can use your phone or the touch screen on the dashboard. Using a dial to navigate on the screen felt like 2003 UX on some hybrid palm pilot/blackberry. Extremely dangerous for me and even if I got used to it, I couldnt imagibe how poking the Map icon would be more dangerouss/slower than using a literal dial while staring at the screen for highlighting as I round robin search through 2-3 inputs...
That's because Apple Carplay wasn't really designed with a linear input method in mind. It should be list-based, not grid-based. Like old Nokia phones, which often only had up-down buttons paired with two action buttons—no left-right.
Give each menu item it's own tone and you could probably navigate it blind after a little bit of practice. Importantly, in this type of system, each menu list should be short—6-7 items max—so that it is easily navigable and memorizable.
The forces the UI to be a flat list in terms of navigation (rather than a 2d-space-filling UX mess). And being a flat 1d list, it encourages the list be short, which means more submenus, which is good!
If menus are consistent, you can mostly control without taking your eyes off the road.
Apple CarPlay already works with this input method.