Apple (AAPL) - Get Report has been driving tech fans and investors crazy for about two years, declining to provide the answer to a very simple question: Is the company developing a car?

After revolutionizing the personal computing and telephony industries, the company has dropped plenty of hints that it's interested in mobility. Tim Cook, Apple's CEO, spoke in 2014 of "opportunities" in the industry, while the tech giant has hired top experts from rivals and kept their activities secret while assigning them a codename, Project Titan.

Yet Apple remains obdurate, declining to reveal the faintest clue of what it's trying to achieve in the car business. The behavior is a cultural legacy of the late Steve Jobs, who was famously secretive about future plans. That policy worked well to keep consumers curious about what new product or feature soon would be revealed.

Elon Musk, Tesla Motors' (TSLA) - Get Report chairman, once mocked Apple as a "graveyard" for former Tesla engineers. Now, Apple has written a letter to the National Highway Traffic Safety Administration, responding to the agency's September request for comment on a series of guidelines for development of self-driving cars.

Apple's letter said little beyond agreeing that self-driving technology will reduce accidents and bring mobility "to those without." The letter urged NHTSA to provide regulatory flexibility in order to foster innovation. If Apple were a start-up, its coyness wouldn't matter.

The new shred of epistolary evidence is exciting Apple fans once more, suggesting the existence of a secret project, perhaps to develop software to sell to automakers or maybe to create a car that will utterly transform personal transportation the way the iPod changed music.

The future of driverless vehicles, as the Internet before it, is a landscape shrouded by fog. The auto industry's cleverest engineers and scientists strain to conjure an image of how a transportation grid that replaces human control with artificial intelligence can operate.

Last week in Munich, BMW briefed reporters on the state of its progress in battery research and driverless car technology. No deep dark secrets were revealed, only enough to persuade the press that BMW is on it, that it embraces the responsibility of keeping consumers and regulators on top of broad technological change.

In early January, several automakers, software makers and suppliers will demonstrate what they've accomplished in advanced mobility at the Consumer Electronics Show in Las Vegas.

The government and most of the incumbent automakers at least are trying to help the public understand what's coming so as to shape and prepare for that future. Critical safety questions such as whether driverless vehicles should provide steering wheels and other controls -- in the event of software breakdown -- remain unanswered.

Apple's understandable interest in playing a role in driverless tech calls for more openness by Cook and a willingness to participate in the global discussion. How vehicles will drive on public roads, transport the masses in crowded global cities, reduce traffic deaths and injuries and contribute to a cleaner environment are ideas that transcend a desire for secrecy.

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Doron Levin is the host of "In the Driver Seat," broadcast on SiriusXM Insight 121, Saturday at noon, encore Sunday at 9 a.m.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.