Uber has unveiled its fleet of self-driving cars in a second U.S. city in three months: San Francisco. Now passengers in the Bay Area can ride in the semi-autonomous Volvo XC90, in which a driver sits in the front seat but does not need to control the vehicle. The first U.S. city to experiment with the vehicles was Pittsburgh. “In coming to San Francisco, there are lots of new things that are being added,” said Anthony Levandowski, chief of Uber’s Advanced Technology Group. “We’re able to handle rain and more inclement weather, and we’re also able to handle now heavy bicycle traffic, which is much more prevalent in the city of San Francisco… And of course the hills are kind of a fun thing.” The expansion to a new city will allow the company to gather data that it can use to improve the vehicles and technology.