“At a minimum, the documents show a pretty cozy relationship between Google and the Department of Transportation, as well as the White House,” said Anne Weismann, the executive director of the Campaign for Accountability. “Google, it appears, had a lot of input into how the federal government was going to deal with driverless cars. I don’t think there’s necessarily anything suspicious or improper about that, but there’s a fine line.”

The fine line Weismann describes has to do with navigating corporate and public interests as they pertain to technology that promises to transform cities, decimate and create entire industries, and save tens of millions of lives this century. It’s natural that federal officials have turned to Google to educate themselves on this technology. Google’s Self-Driving Car Project, which launched in 2009, is one of the best known and oldest of its kind among its peers in Silicon Valley. Google has also been considerably open with the public about its progress, sharing monthly reports about its software with the public and otherwise articulating its vision for a driverless future. Though it isn’t unusual for government officials to rely on corporations for technological expertise, it’s difficult for the public to glean how closely these entities are collaborating when such work happens in private. “Any time we’re looking at a specific group of emails, we’re only getting a small piece,” Weismann said. “To a large degree, unfortunately, [public understanding of what’s going on] depends on how transparent a particular administration wants to be. And the trend seems to be moving away from that. We’re given less and less access.”

The National Highway Traffic Safety Administration released a short policy statement on autonomous vehicles in 2013, and it hosted a pair of public meetings about the technology earlier this year, but much of the federal government’s work on the technology—including plans for regulatory oversight—has occurred behind closed doors.

There will be more opportunities for the public to participate in policymaking discussions once the new federal guidelines are issued, according to a senior Department of Transportation official who agreed to speak on-record only if his name wasn’t used. In the meantime, the Campaign for Accountability’s trove of emails offers a unique glimpse at tandem efforts between federal officials and Silicon Valley executives to bring self-driving vehicles to the masses.

The emails outline years of regular communications between top officials at Google and senior leaders in the Department of Transportation—including the head of Google’s Self-Driving Car Project; the project’s program manager; the project’s head of business development; several Google vice presidents; Google’s head of public policy; a Google product manager; a Google user-experience researcher; top Google engineers; Google lawyers; the deputy director of NHTSA, the agency’s top lawyer; NHTSA’s director of policy; the director of the Vehicle Research And Test Center; and several other top leaders from the federal Department of Transportation. The documents are focused on Google, but they also show plans for occasional meetings with officials at Bosch, Audi, Honda, Toyota, VW, BMW, and Tesla.