Idk about risk: that is hard to establish. There are so many conditions in which an automatic pilot hasn't been tested. We don't even know the factors involved in estimating the risk: e.g., is it dependent on the human co-pilot? And self-driving cars may change the car usage patterns, exerting a contextual influence on the risk.

Then there's the question of responsibility. Who will be held responsible when the automatic pilot is driving? If it's the human, then a high risk of causing an accident will be unacceptable to many drivers.