Cade Metz / New York Times:
After predicting autonomous vehicles would be commonplace by 2021, the industry is resetting expectations and committing to years of further R&D  —  Many in Silicon Valley promised that self-driving cars would be a common sight by 2021.  Now the industry is resetting expectations and settling in for years of more work.

Source: http://www.techmeme.com/210526/p2#a210526p2