Humans are terrible drivers. The open question is are self driving cars overall safer than human driven cars. So far the only people talking either don't have data, or have reason cherry pick only parts of the data that make self driving look good. This is the one exception where someone seemingly independent has done analysis - the question is are they unbiased, or are they cherry picking data to make self driving look bad (I'm not familiar with the source so I can't answer that)
Either way more study is needed.