Rumors of a self-driving vehicle from Apple have persisted for months but until now, the general consensus was that the Cupertino-based company was in the early stages of exploring the idea. Documents recently obtained by the Guardian, however, paint quite a different picture.

Correspondence reveals that in May, Apple engineer Frank Fearon reached out to officials from GoMentum Station to gather information regarding when the space would be open for testing and how they would need to coordinate with other parties using it.

GoMentum Station is located on a former navy weapons station in Concord, California. The Contra Costa Transportation Authority (CCTA) is in charge of the private facility which, with 20 miles of paved roadway, is the largest secure test facility in the world.

The CCTA says the area will become the center of connected vehicle and autonomous vehicle research. Honda and Mercedes-Benz have already conducted experiments on location, we’re told.

Randy Iwasaki, CCTA executive director and owner of GoMentum Station, told the publication they had to sign a non-disclosure agreement with Apple. As such, they can’t reveal anything more than the fact that Apple has come in and is interested.

No further details were skimmed from the documents although one would assume that if Apple is already seeking a proving ground, its autonomous electric car project – codenamed Project Titan – must be much further along than most thought.