At the blockbuster plenary sessions, the chairs stretched so far back that even the most youthful Silicon Valley college dropouts-turned VC hoovers had to squint to see the action up in front. A handful of large projection screens hung between the ballroom’s chandeliers, displaying loop-de-looping flow charts on vehicle safety systems, sensor alignments, liability law.

But despite the best efforts of the downtown San Francisco Hilton’s air conditioners, the air shared by the attendees of this year’s Automated Vehicles Symposium was thick with secrets and doubt. Eight years after Google first showed its self-driving car to The New York Times, the autonomous vehicle industry is still trying to figure out how to talk about itself.

Over the three-day conference, engineers, business buffs, urban planners, government officials, and transportation researchers grappled with how to tell the public that its wonder drug of a transportation solution will have its limitations. For at least a few decades to come.

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In a market that could be worth $7 trillion by 2050, the players have a powerful incentive to stay mum. And if anyone forgot that, Tuesday’s news that FBI agents had arrested an ex-Apple engineer en route to China, charging him with stealing blueprints of the company’s autonomous vehicle circuit board, reminded them. If any player talks too much, who knows what snatches of information might slip out? There are plenty of competitors waiting to profit.

And yet, the reasons for speaking more loudly and clearly about the goals and realities of self-driving have snapped into focus. In March, an autonomous Uber testing in Tempe, Arizona, struck and killed a woman crossing the street. A AAA survey taken after the incident found American unwillingness to ride in an autonomous vehicle jumped by 16 percent. The crash hung over the symposium as both a lesson in what’s at stake and in what can happen if the autonomous vehicle industry gets things wrong.

In years past, this conference has been all about big pronouncements. Last year, Lyft’s policy chief told the audience that most of the service’s rides would be automated in five years. This year, attendees heard less about commercial launches and more about the minutiae of safety procedures. Lyft’s 2018 presentation, by self-driving car president Nadeem Sheikh, dodged firm deadlines all together.

In an industry built on eliminating human error, insiders have started to admit that building a flawless vehicle will be almost impossible. In fact, they are starting to admit that they need to start admitting it publicly.

“Safety should be foundational to everything you do in this area,” said Mark Rosekind, a former National Highway Traffic Safety Administration and National Transportation Safety Board official who now heads up safety and innovation at the secretive autonomous vehicle startup Zoox. “But understand that on that path, crashes will continue to happen.” How do you go about telling the public this sort of truth, that zero road fatalities is, for the time being, a fantasy?

During her keynote address on Tuesday, Department of Transportation Secretary Elaine Chao suggested one avenue. “Let me challenge you to step up, and help educate the public about this new technology,” she said. “That is so important, because without public acceptance automated technology will never reach its full potential.”

Chao appears to be onto something there. The public is primed to expect autonomous vehicles to be perfect. When the tech isn’t, people are surprised—and scared. Earlier that morning, Kristin Kolodge of the market research firm JD Power presented her findings on what consumers expect from AVs. “The car is meant for accidents not to happen,” one respondent told the firm. “[Accidents] Should never happen,” said another. For self-driving vehicle developers, that’s an unfortunate expectation. A person who expects infallible technology will be disappointed.