Google's self-driving cars had logged 140,000 miles before the project was revealed

In the October 9, 2010 Google blog post “What we’re driving at,” Sebastian Thrun disclosed that Google’s self-driving cars had already driven 140,000 miles on public roads, including San Francisco’s hilly streets, the Golden Gate Bridge, highways, and toll booths, with the car driving itself. A trained safety driver and a software operator were always present during these tests.