[dTal]

How does it know you're on a motorcycle? I can imagine that it would be possible to detect fairly reliably with smartphone sensors (correlate curved ground path with gyro tilt), but it's astonishing and frightening that they would put in the effort to go that far.

[blamazon]

I think you pretty much described the mechanism there. My friends and I have experimented with "riding like a car" and we can trick the algorithm for short distances if we really think about keeping the phone upright.

The keywords to learn more seem to be "activity recognition API" and I'm pretty sure they have been doing the motorcycle thing for the better part of a decade:

https://developers.google.com/location-context/activity-reco...

[SanjayMehta]

Some 4-5 years ago someone analyzed an Android phone and showed they even know when you've exited a car.

I'll update this comment with a link when I find it.