The specific use of phones is barely discussed but worth doing so.

For example talking on a phone, or even in a car, is highly distracting and delays reactions. Passengers are generally more sensitive to context and weirdly somehow less distracting than phones. So that's something important to consider.

Listening to the radio is slightly distracting, and likewise listening to the radio played through the phone with notifications off. Doing this is probably fine and we should design roads and cars around the idea that people will listen to music, or sing, or whatever.

Fiddling with the radio is extremely dangerous, I'm sure we've all been rear ended or nearly so by someone doing it, and probably had a couple of "oops shouldn't have done that" moments ourselves. Likewise fiddling with phones.

The idea of banning all phone usage is a non starter, but we can probably introduce regulations like phones disabling certain features while cars are in motion but leaving them as useful for navigation and music etc.