Three driverless cars bring a San Francisco street to a standstill, halting traffic and blocking people from leaving. #fox #media #breakingnews #us #usa #new #news #breaking #foxnews #sanfrancisco #california #tech #technology #ai #robotaxi #driverless #selfdriving #waymo #transportation #traffic #incident #publicsafety #streets #city #america Subscribe to Fox News: https://bit.ly/2vBUvAS Watch more Fox News Video: http://video.foxnews.com Watch Fox News Channel Live: http://www.foxnewsgo.com/