So, use an app with offline data and maps for the areas you are roaming into...

Perhaps I didn't make my point very clearly. Relying on a phone for in-car updates, such as traffic, is already an issue due to data roaming. Relying entirely on the phone will exacerbate this.

I appreciate there are offline mapping solutions, which I noted. However, there are probably also other edge cases I haven't specifically considered.

How do you propose you get in-traffic updates without some sort of data feed? You can't turn it off in any apps? Also, does your in-built navigation have this feature?

I think we really are talking at cross purposes.

Yes, my in-built navigation system requires me to tether my phone to receive traffic updates. No tethering, no traffic updates or traffic camera alerts.

I don't have an alternative solution and understand a data connection is required for this functionality to work.

My point was that already I lose this service if I travel out of my own country and turn the data connection off to save money. If the car only had "a screen and a few buttons", relying on the phone for everything, much more functionality could become hamstrung without a data connection. I appreciate there are offline mapping solutions, but there are probably other service edge cases I haven't considered.

But the UI wouldn't be stuck with something from 5+ years ago for a car that should last 15-20 years. My year old car's screen came with a UI that felt dated out of the box. If it were my phone driving the thing, at least the UX would be current, and with data, even more could work... I wouldn't be any less well off, even without data, unless my phone were broken or forgotten.

So you're not responding to the parent comment at all? The comment:

> I think it should be that way with cars. Just include a screen and some buttons, then let people connect their smart phones.

Your situation as described:

A built-in navigation system which is quite a bit more than just a screen and some buttons. It just happens to use your phone for data connection.

He's saying that he disagrees with the parent comment. That just a screen is great until it means you can't navigate.

Right. Except he doesn't just have a screen. He has some navigation system onboard that happens to use the phone's data system. Not just a screen. If it was just a screen you could hook your phone up to it and see the phone's screen. And then on the phone you use any of the many offline navigator apps. Which is perfectly viable, if it was just a screen, which he doesn't have.

What other services would require no data if it were integrated into your car but would require data if it were integrated into your phone?

There is an FM system in use in some countries (I know it works for sure in Germany). You just need to have a GPS unit with this receiver. More info here https://support.garmin.com/faqSearch/en-US/faq/content/i34WV... (it is the last one mentioned)

At least the EU recognizes the increased importance of data roaming and are working to abolish the extra charges hopefully this year.

I live in Austria, so can relate. But "just a screen and buttons" does not mean "permanent internet access". It could/should work without inet as well. But really, who wants car nav systems, when Google Maps on my phone is so much better?

First world problems :)