alt Hacker NewsThey're not. Use any car's heads up display and you can configure an enormous number of things. Even if there was somehow a pure separation, things such as "playing video while the car is moving" are regulated in many jurisdictions and would land firmly in the "UI" layer.
You can detect the car is in motion or not without talking to the engine computer. Just like my phone can tell I'm in motion without connecting to the car at all. You're trying to justify a bad design with bad reasoning