I have an iPhone 14 Pro and Apple Watch SE. My phone is connected via Bluetooth to my car (it is NOT CarPlay). This feature has been working for at least a couple of iOS versions, however, I'm currently running iOS 17 Public Beta and WatchOS 10 Public Beta.
When I start my car, my watch tells me how far I'm from home and if it's light/heavy traffic. As far as I can tell, Apple Maps is telling me this info. I do have Google Maps installed as well, but don't think it's that. This is NOT the "Find my car" feature.
I recently moved (in the last few days) and updated my "Home" on both Apple Maps and Google Maps, however, when I start my car from my new address, it tells me how far I am from my old address. When I'm away from both addresses it still tells me the old address as well. I need to figure out how to update the new address so it'll tell me that distance when I start my car.