My parked car got gashed in a hit-and-run two weeks ago. I found a star witness: the car itself.

Like mine, your car might have cameras. At least one rearview camera has been required on new American cars since 2018. I drive a Tesla Model 3 that has eight lenses pointing in every direction, which it uses for backing up, parking and cruise control. A year ago, Tesla updated its software to also turn its cameras into a 360-degree video recorder. Even when the car is off.

All those digital eyes captured my culprit — a swerving city bus — in remarkable detail.

Tesla chief executive Elon Musk calls this function Sentry Mode. I also call it Chaperone Mode and Snitch Mode. I’ve been writing recently about how we don’t drive cars, we drive computers. But this experience opened my eyes.

I love that my car recorded a hit-and-run on my behalf. Yet I’m scared we’re not ready for the ways cameras pointed inside and outside vehicles will change the open road — just like the cameras we’re adding to doorbells are changing our neighborhoods.

It’s not just crashes that will be different. Once governments, companies and parents get their hands on car video, it could become evidence, an insurance liability and even a form of control. Just imagine how it will change teenage romance. It could be the end of the idea that cars are private spaces to peace out and get away — an American symbol of independence.

Tesla's "Sentry" mode activates cameras around the car and records nearby motion, such as a hit-and-run or just a passerby. Geoffrey Fowler tested it out. (The Washington Post)

“You are not alone in your car anymore,” says Andrew Guthrie Ferguson, a visiting professor at the American University Washington College of Law and the author of “The Rise of Big Data Policing.”

The moment my car was struck, it sent an alert to my phone and the car speakers began blaring ghoulish classical music, a touch of Musk’s famous bravado. The car saved four videos of the incident, each from a different angle, to a memory stick I installed near the cup holder. (Sentry Mode is an opt-in feature.) You can watch my car lurch when the bus strikes it, spot the ID number on the bus and see its driver’s face passing by moments before.

This isn’t just a Tesla phenomenon. Since 2016, some Cadillacs have let you store recordings from four outward-facing cameras, both as the car is moving and when it’s parked. Chevrolet offers a so-called Valet Mode to record potentially naughty parking attendants. Sold with Corvettes, they call this camera feature a “baby monitor for your baby.”

Now there are even face-monitoring cameras in certain General Motors, BMW and Volvo vehicles to make sure you’re not drowsy, drunk or distracted. Most keep a running log of where you’re looking.

Your older car’s camera may not be saving hours of footage, but chances are it keeps at least a few seconds of camera, speed, steering and other data on a hidden “black box” that activates in a crash. And I’m pretty sure your next car would make even 007 jealous; I’ve already seen automakers brag about adding 16 cameras and sensors to 2020 models.

The benefits of this technology are clear. The video clips from my car made a pretty compelling case for the city to pay for my repairs without even getting my insurance involved. Lots of Tesla owners proudly share crazy footage on YouTube. It’s been successfully used to put criminals behind bars.

But it’s not just the bad guys my car records. I’ve got clips of countless people’s behinds scooching by in tight parking lots, because Sentry Mode activates any time something gets close. It’s also recording my family: With another function called Dash Cam that records the road, Tesla has saved hours and hours of my travels — the good driving and the not-so-good alike.

We’ve been down this road before with connected cameras. Amazon’s Ring doorbells and Nest cams also seemed like a good idea, until hackers, stalkers and police tried to get their hands on the video feed. (Amazon founder and chief executive Jeff Bezos owns The Washington Post.) Applied to a car, the questions multiply: Can you just peer in on your teen driver — or spouse? Do I have to share my footage with the authorities? Should my car be allowed to kick me off the road if it thinks I’m sleepy? How long until insurance companies offer “discounts” for direct video access? And is any of this actually making cars safer or less expensive to own?

Your data can and will be used against you. Can we do anything to make our cars remain private spaces?

Where self-surveillance goes wrong

My Tesla hasn’t fully realized its potential as a rolling self-surveillance machine. So far.

On several fronts, Tesla’s cameras work differently than connected home security cameras. I can’t discern whether these differences are deliberate privacy by design or just a reflection of the newness of this tech in cars. Tesla didn’t answer questions I sent it, which hardly builds trust. As a customer, I deserve to know what my car is recording and how it can be used.

Their design choices may well determine our future privacy. It’s important to remember: Automakers can change how their cameras work with as little as a software update. Sentry mode arrived out of thin air last year on cars made as early as 2017.

We can learn from smart doorbells and home security devices where surveillance goes wrong.

The problems start with what gets recorded. Home security cameras have so normalized surveillance that they let people watch and listen in on family and neighbors. Today, Tesla’s Sentry Mode and Dash Cam only record video, not audio. The cars have microphones inside, but right now they seem to just be used for voice commands and other car functions — avoiding eavesdropping on potentially intimate car conversations.

Tesla also hasn’t activated a potentially invasive source of video: a camera pointed inside the car, right next to the rear view mirror. But, again, it’s not entirely clear why. Musk tweeted it’s there to be used as part of a future ride-sharing program, implying it’s not used in other ways. Already some Tesla owners are champing at the bit to have it activated for Sentry Mode to see, for example, what a burglar is stealing. I could imagine others demanding live access for a “teen driving” mode.

(Tesla has shied away from perhaps the most sensible use for that inner camera: activating it to monitor whether drivers are paying attention while using its Autopilot driver-assistance system, something GM does with its so-called SuperCruise system.)

In other ways, Tesla is already recording gobs. Living in a dense city, my Sentry Mode starts recording between five and seven times per day — capturing lots of people, the vast majority of whom are not committing any crime. (This actually drains the car’s precious battery. Some owners estimate it sips about a mile’s worth of the car’s 322-mile potential range for every hour it runs.) Same with the Dash Cam that runs while I’m on the road: It’s recording not just my driving, but all the other cars and people on the road, too.

The recordings stick around on a memory card until you delete them or the card fills up, and it writes over the old footage.

With other connected cameras, there’s also a privacy concern that they are recording people without their permission or knowledge. Chevrolet potentially ran afoul of eavesdropping laws when it debuted Valet Mode in 2015, because it was recording audio inside the cabin of the car without disclosure. (Now they’ve cut the audio and added a warning message to the infotainment system.) When it’s on, Tesla’s Sentry Mode activates a warning sign on its large dashboard screen with a pulsing version of the red circle some might remember from the evil HAL 9000 computer in “2001: A Space Odyssey.”

My biggest concern is who can access all that video footage. Connected security cameras let anybody with your password peer in from afar, through an app or the Web. You can’t do that on cars — yet. Tesla and GM require you to physically pull the memory stick out of the car to watch the footage. Requiring local access avoids some potential problems.

But streaming video from your car isn’t out of the realm of possibility: Teslas, like most new cars, come with their own independent cellular connections. And Tesla, by default, uploads clips from its customer cars’ external cameras. A privacy control in the car menus says Tesla uses the footage “to learn how to recognize things like lane lines, street signs and traffic light positions.” (It says the clips are made anonymous, but it still might have pictures of my house or even me.)

What about other companies? It’s not hard to imagine the value of driving footage to insurance firms. Already, companies such as GM have deals with insurance firms to share data about your driving in exchange for discounts, though it doesn’t include video. (It’s worth noting the presence of all those cameras hasn’t lowered insurance rates on a Model 3, which are sky high.) Now imagine what Google or Facebook might want to do with that data on everywhere you drive.

All of which raises a constitutional question: What about the police? Amazon’s Ring has raised hackles by partnering with more than 400 local police in the United States to map out where consumers have installed the devices and make it easier to request footage.

I was happy to turn over my car’s video files to the police, but I could imagine lots of other cases when it wouldn’t be to my advantage. What if I had been the perpetrator of the crash? There is a lot of gray zone when cars are also measuring where you’re looking and how you might have been “reckless” right before or after a crash. We’re all bad drivers sometimes.

Video from security cameras is already routine in criminal prosecutions. In the case of Ring cameras, the police can make a request of the homeowner, who is free to say no. But courts have also issued warrants to Amazon to hand over the video data it stores on its computers, and it had to comply.

It’s an open question whether police could just seize the video recordings saved on a drive in your car, says Ferguson, the law professor.

“They could probably go through a judge and get a probable-cause warrant, if they believe there was a crime,” he says. “It’s a barrier, but is not that high of a barrier. Your car is going to snitch on you.”

Without Sentry Mode, I wouldn’t have known what hit me. The city’s response to my hit-and-run report was that it didn’t even need my video file. Officials had evidence of their own: That bus had cameras running, too.

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