Under carefully limited conditions, and for the specific limited aspects that were measured and reported. At a AAAS Annual Meeting a few years ago, the research heads of several car companies were asked about prospects for unlimited conditions. All but one hawed and hemmed. That one didn't pretend, saying [this is a paraphrase] "Nobody knows how to do that."
Self-driving cars are dramatically safer than human drivers, not just marginally. https://spectrum.ieee.org/are-self-driving-cars-safe