What you're referring to has nothing to do with the location of the vehicle itself (which is what this article is about), but the location of external objects relative to the vehicle.
The most important thing a self-driving vehicle accurately needs to track about itself is its current speed. Next would be the current state of the steering wheel, accelerator, and brakes (and perhaps whether the driver is trying to take over to avoid an accident). I suppose there are a number of other things you wouldn't normally think about for a moving vehicle such as whether any doors are currently open (it sounds stupid, but it's possible). There are plenty of other (mostly) fixed constant values such as vehicle dimensions, weight, braking power, turning radius, etc. that it needs to know to determine the best way to avoid obstacles/accidents. I'm sure I haven't thought of all of them, but none of those that I can think of are location-based.