The last time Google’s self-driving car team checked in with us over a year ago, when it announced Google’s cars had driven more 300,000 accident-free miles. Today, the team announced in a blog post that the cars have now driven over 700,000 miles. The team has been focused on improving the self-driving cars in cities rather than on freeways, mostly testing this in Google’s hometown of Mountain View, California, and this focus on city driving has produced some impressive results.

The sensors on the self-driving cars can now detect with impressive detail everything from pedestrians and buses to “a stop sign held up by a crossing guard, or a cyclist making gestures that indicate a possible turn.” It can do this all, of course, without getting distracted or tired, as human drivers are prone to doing. Self-driving cars could cut down on vehicle-related injuries by 90%, since most car accidents are caused by human error.

Right now, Chris Urmson, the director of Google’s self-driving car project, writes, “We still have lots of problems to solve, including teaching the car to drive more streets in Mountain View before we tackle another town.”

Still, he is optimistic about the future of the project, saying, “with every passing mile we’re growing more optimistic that we’re heading toward an achievable goal—a vehicle that operates fully without human intervention.”

Embedded below is a video showing one of Google’s self-driving cars navigating the streets of Mountain View, California.

In addition to writing for BGR, Ben also helps out at two student publications at the University of Chicago. He writes for The Daily Sophist and copy edits for The Chicago Maroon.