What do other firms Have to say about the data Google’s report offered the most detail and explanation, by far. The leader of its self-driving car project, Chris Urmson, said that while he considers the results encouraging, they show room for improvement. Google reported that, in 424,000 miles of testing since autumn 2014, its cars needed human help 341 times due to serious safety issues. The data they contain are the most detailed look yet at how safely the prototypes are performing.Traditional automakers and technology companies such as Google are investing hundreds of millions — probably billions — of dollars in a race to market. While self-driving cars already are being tested on public roads, newly released safety data support the cautionary view that the technology has many miles to go before people can sleep at the wheel. After all, by the company’s own analysis, there were 11 instances in which the car would have had an accident if its driver had not taken over.The fact that Tesla reported no “disengagements” was puzzling.

A spokesman for Nissan, which has said it wants to have “commercially viable autonomous drive vehicles” by 2020, said disengagements are an expected part of testing. The data on “disengagements” of the self-driving technology document the gap.Wait, Teslas are perfect No. What are the blind spots in the data It’s hard to draw direct comparisons between companies. Tesla isn’t talking. And that, for now at least, traditional automakers remain far behind.The DMV released those reports on Tuesday.

While self-driving cars already are being tested on public roads, newly released safety data support the cautionary view that the technology has many miles to go before people can sleep at the wheel. It could reflect a company interpretation of the reporting requirements.Google was one of seven companies required to disclose to California’s Department of Motor Vehicles the number of times a trained test driver had to seize the wheel either because of a technology failure or because a prototype car was driving unsafely. Just go online and you’ll find videos where the “autopilot” feature already in some Tesla sedans drove erratically enough that the driver grabbed the wheel. That said, Google’s numbers do compare favorably to other companies.

Some questions and answers about what the data reveal about the state of the technology:What became clear this week It became clear that even Google, which has done the most testing in California by far, is not on the cusp of perfecting a car that doesn’t need a driver. The raw numbers say nothing about the conditions the cars were tested nylon rollers under, or how hard the companies pushed them. Other reports were not nearly as descriptive. If one company ventured to the hilly, hectic streets of San Francisco, its disengagement numbers likely would spike.