Uber gets a lot of criticism here for their business practices but from a technical standpoint this is a tremendous achievement in improving urban location accuracy. I hope they'll consider offering it as a separate API someday since it would obviously be valuable for many use cases beyond transportation.
Then it went dark. So Uber deserves credit for funding the continuing development of this tech, but it isn't open when the pre-acquired company could have provided exactly what you want. I really wish there were different (but still financially rewarding) avenues for technology like this to go down, other than being swallowed whole by BigCorp and disappearing from the world.
I wanted to come in to say this as well. I am not a fan of the previous practices Uber has had and I hope they have changed some of their ways but I have always appreciated their willingness to publish their findings from an engineering perspective to the world.
The calculations look pretty complex. I think doing it on mobile devices would impact battery life, which is why Uber built a server farm instead of just adding it to their Android app.
