Although everyone can agree that self-driving cars will be hitting the market in the near future, nobody can agree on when that’ll actually happen. Google’s prediction that fully autonomous cars will become available to consumers in five years or so has been the most aggressive of all the predictions for a while, but it looks like Ford holds that honor now. According to CEO Mark Fields, it’s the legal and regulatory obstacles that need to be overcome before self-driving cars can start hitting the market, more so than the technological ones, and he believes that will happen within the next four years.