so about half a year ago when they were preparing for public release they decided to change safety level constant from 0.99 to 0.999 That's my theory as well.

so about half a year ago when they were preparing for public release they decided to change safety level constant from 0.99 to 0.999 That's my theory as well. Remember, Uber killed a pedestrian earlier this year. Fortunately that didn't result in self-driving cars being banned or regulated out of existence, but they may not a get a third chance, so it makes sense to be even more cautious after that.