[themoonisachees]

Google maps (and your phone's location services) seldom rely only on GPS.

For one, accelerometer-based location has become pretty good. You can usually get by for a few kilometers on the average road.

For two, Google maps is aware that you are driving, and this it sticks to roads, especially ones that are on your itinerary, because of your GPS registers as the middle of a field, it's more likely that you're experiencing GPS issues rather than you driving at 130km/h in a potato field.

Finally, location services are amplified by nearby wifi signals, mapped by google with street view. Your phone can say "here is the Mac address of every wifi network I can see and a rough estimate of my position" and Google's services can very accurately triangulate where you are.

[cft]

Does accelerometer-based location algorithm integrate the acceleration readings to get the phone displacement? Is it a part of the phone operating systems ?

[themoonisachees]

It tries. Accelerometer-based positioning is best used with camera displacement, which isn't used in Google maps driving mode (though there was? Is? An experimental on-foot mode that showed directions in AR).

the accel-based positioning I'm pretty sure is implemented app-side, not os-side, but I could be mistaken.

[rightbyte]

Probably not. Maybe to like know where you are turning in a round about. But the drift is too big to be useful over any distance.