That's not how it works. Autonomous cars would need to be a couple of orders of magnitudes safer than humans. Human killing human is one thing and machine killing humans is quite another. But more importantly, the blame currently gets distributed over many people's insurance policies. For autonomous cars, all blame would end up at car manufacturer. Imagine you getting blamed for every single accident that happens ever. Even if you have achieved human-level safe driving and chance of an accident is 0.001%, multiplying that with millions of vehicles is a huge number. A dominant autonomous car manufacturer will be blamed for 4 human deaths each hour even if they have achieved human-level safety.