I just read a very interesting article in Popular Science about repo trucks and their new auto-scanning license plate cameras.

The cameras are mounted on all four corners of their trucks, as as they drive around they automatically scan any license plate number that comes into vision and compares it with an online database of 1.8 billion other scans. (Even though there a quarter of a billion cars in total in the U.S., vehicles are often scanned up to a dozen times or more.) A single truck can scan as many as 8,000 plates in one day.

If he gets a hit, a notification comes up on the repo driver's screen telling him the vehicle is past due. Otherwise, the data gets saved and sent back to the database along with the license plate number, GPS coordinates of the scan, and a time stamp. Using this data, repo firms can build profiles predicting a driver's home address, workplace, favorite restaurant, gym, etc. The system was so effective firms started hiring "scouts" to drive around with a $23,000 camera suite just to suck up license plates all day.

These databases came online for use by any paying customer (usually repo firms) in the early 2000s, and by 2009 repos were purchasing their own camera systems to be installed on trucks. It's safe to assume law enforcement has been playing this game even earlier, and possibly have special access to other license plate databases.

My question is, what would be the most discreet way to defend against such blatant data-mining attacks? I don't mind answering questions to LE, but like most of the equipment and tools I own that some would consider "iffy" (even if they're just ignorant of the law), I'd rather avoid unnecessary attention to it if I can. If the final thing could look like a bedazzled license-plate frame that would be great.

I own my car in full and don't have any debt, but the data-capture is indiscriminate. Nobody knows how these databases are secured, who has access, or if there are backdoors installed.

I'd rather just "opt-out".

I'm wondering the cleanest way to non-confrontationally "mask" my plate to such scans. The cameras they show in the pictures use IR lights (usually for night vision), so I'm wondering if a sufficiently bright IR light near my license plate would obscure the camera from reading all the numbers?

IR light would mean it wouldn't be visible to the human eye, and if the camera couldn't get a read, it would just give up. Cameras collect data in frames, sending them to a processing unit that analyzes each frame looking for a recognizable pattern — like a license plate — so every frame that doesn't contain one is technically a "failed scan".

Is it possible to have a light bright enough? I would need a prototype and a camera that picks up IR to test it, so I was wondering if anybody else has more understanding or experience with this already?

Also, any alternative ideas to defend against this are welcome.

Edit: So, I've done some more research, and found this. He describes blocking a surveillance cam from watching your face by building the LEDs around some glasses and a hat. Like he mentions with this "super-bright LEDs" method, you will highlight yourself to the camera but it will not make out the features of your face. Since this is computer vision we're talking about and not a security guard watching the screen, this is not an issue for my project.

I think the next step is to order a roll of IR LEDs, see if they work with my webcam or camera, and test arrangements on a license plate.

Like someone commented much earlier, you can still get scanned while parked unless you wired them to stay on, in which case you're dealing with car battery drain problems. I probably won't go that far with this project. It's sunny >300 days a year here, so my first thought for that was a roof-mounted solar panel. :-)

Edit 2015-01-21: EFF: What You Can Learn from Oakland's Raw ALPR Data

  • 4
    You might get in trouble if it prevents law-enforcement readers from operating. You might check if your local jurisdiction has rules against obscuring plates. If the system alerts cops that you're doing something like this, they might pull you over to find out why. This would have to be on 24/7 to prevent reads while parked, watch out for draining the batteries. If your car gets stolen, this will work against you. Commented Jul 6, 2014 at 23:42
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    @Clockwork-Muse — I updated the question to clarify your concerns about failed scans notifying the driver. As for legality, if I were to ever get pulled over I would point out there are no laws (as of yet) protecting the right of the gov't to indiscriminately log the whereabouts of every citizen; same as there are no laws preventing me from "opting-out" of such sweeping dragnet programs. (If there ever where any such laws tried, it would be my hope that national outrage occur)
    – IT Bear
    Commented Jul 7, 2014 at 1:14
  • There are laws against this in many countries, including the UK.
    – Rory Alsop
    Commented Jul 7, 2014 at 11:12
  • I've checked into the laws in the U.S., all of them appear to be about obscuring the plate visually, or explicitly prohibiting red-light camera "tricks" which appears that most don't work anyway. Let me be clear on this: I don't want any answers suggesting anything "illegal". What I'm proposing would conform with all existing laws in my country. (an IR light to beat an IR camera). Red light cameras do not use IR, as we can tell by the blinding flash we see when they get a hit. This would be a specific tool for a specific purpose (prevent relentless data mining)
    – IT Bear
    Commented Jul 8, 2014 at 23:21
  • 2
    I asked a question on meta about this.
    – jliv902
    Commented Sep 23, 2014 at 16:17


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