Apple is doing something with cars, whether it's building a car itself or just researching software for self-driving cars. But whatever it's doing, it's happening on a tiny dead end street in an industrial neighborhood in Sunnyvale, California, according to a slew of reports.

Neighbors have complained about "motor noises" coming from this complex at night.

The complex has been linked to Apple through public records, which also suggest that one of the offices have had a "lube bay," a "wheel balancer," "tire changer," and "wheel sensor" installed.

So when I was in Silicon Valley last month, I decided to drive by to check out this facility that Apple has reportedly codenamed "Rhea." (In Greek mythology, Rhea is a Titan, and Apple's car project is reportedly called "Project Titan.")

When I got there, I discovered a complex of boring office buildings with frosted windows. The street was pretty barren and the parking lots were empty. It was a Sunday, after all.

But in front of 175 San Gabriel Dr, I spotted two brand new Tesla Model X SUVs — the new electric SUV that came out earlier this year. They're pretty rare. Tesla's only sold about 7,000 of them, and two of them were in front of Apple's car office.

The SUVs aren't necessarily Apple's. The cars could have been just randomly parked on the street, or they could have belonged to Apple employees — lots of Apple workers drive Teslas, and some of its engineers may have been among the first to buy the new SUV.

But they were the only cars on the street on that Sunday. Neither had California plates — one had an special Illinois "interstate transport" plate, and the other had a generic Tesla "zero emissions" paper plate.

Apple did not respond to a request for comment.

Car companies regularly buy other companies' cars so they can see what the competition is up to. Ford bought one of the first Model Xs sold in the United States, for example. Since Apple's automotive ambitions center around electric cars, it would make sense to get acquainted with the Model X.

"It is common for auto companies to buy competitors' cars and tear them apart," Michelle Krebs, senior analyst for Autotrader.com, told Business Insider. "I think this would now apply to tech companies thinking about working on automotive."

The street has scary looking signs in front of its parking lots warning that trespassing is a crime, although San Gabriel Drive, where we took these photos, is a public road.

They look like this:

That bottom sign looks a lot like the standard sign Apple uses to warn people from trespassing, only it's missing any mention of Apple. Here's an Apple-specific sign we saw at another spot:

I didn't get a closer look at any of the offices. A security officer, wearing what looked like a black hat with an Apple logo, pulled up in a white Prius to keep an eye on me, so I drove away.

Do you know anything about Project Titan or Apple's car? Email the author at kleswing@businessinsider.com.