A new article in the Washington Post asks the question, “Will driverless cars really save millions of lives?” A lack of data, it says, makes it hard to know.

The article quoted Chris Urmson, who spoke to transportation engineers in Washington this year when he was the chief of Google’s self-driving car project: “One of the hardest questions to answer is, ‘How do these cars compare to human drivers?’  And part of the reason why that’s hard is we don’t actually have a good understanding of how good human drivers really are.”

Another problem is that the U.S. government keeps no comprehensive database of crashes, according to the article, which makes difficult what should be an easy task: determining which cars are more likely to crash, human-driven ones or those run by software and sensors.

To read the full article, click here.