I was just about to post this!

Uber would be crippled if it lost access to the industry-leading mapping application, and alternatives— such as AOL's MapQuest, Apple Maps, and a host of regional players—are widely seen as inferior.

I've seen some people in the comments on Hacker News suggest OpenStreetMaps or TIGER data as an alternative for Uber. While they're good for mapping purposes, they falls short to use just those sources as a foundation to a self-driving car, as you can see here.