Feb 132011

Are Seattle police tracking the movement of law-abiding citizens?  They have the technology to do so.  I’d like to find out how they’re using automated license plate recognition (ALPR) now and what limitations we’ve placed on use of these devices.

Thursday, on my way to a meeting of the Capitol Hill Chamber of Commerce‘s Clean & Safe committee at the Seattle Police Department’s East Precinct, I noticed a police car with what looked like three cameras mounted on its roof:

Upon closer inspection, it appeared that each contained two lenses and an array of LEDs.  Here’s a closeup:
image closeup of camera on police car roof

After the meeting, I asked Officer Casey Sundin (who is on the clean & safe committee with me) about the cameras.  He told me that they’re license plate scanners — technically, cameras, but producing license plate numbers, not images — and are used to look for stolen vehicles.  I was surprised.  I’ve heard of these devices, but I didn’t know we were using them in Seattle.

I have mixed feelings about our police investigating every single vehicle that squad car passes, but if they’re just checking plate numbers of vehicles on the public roads against a list of those of stolen vehicles and storing information only about matches, it would be hard to argue against such a system.  My car was stolen off the streets of Capitol Hill twice about six or seven years ago.  It was recovered both times.  The first time, it was discovered in a residential area of the University District a couple weeks after the theft.  There was a parking ticket on the windshield, and it had been issued after I reported the car stolen.  So it seems SPD were not looking very hard for stolen cars back then.

Friday, ACLU of Washington noted on their Facebook page that there was a great discussion going on in the comments of their May 26, 2010, post about license plate recognition, and encouraged readers to join in.  In that post, Brian Alseth (director of ACLU-WA’s Technology and Liberty Project) writes about automated license plate recognition (ALPR) systems, but not specifically about SPD’s system:

Automatic License Plate Recognition systems or “ALPR” consist of cameras that are either mounted on a vehicle or a pole. The cameras capture an image of the license plate of every passing vehicle, including cars travelling in the opposite direction and cars parked along the curb. Software then converts the license plate image into text and the system compares the license plate number against a hot list of stolen cars, outstanding warrants, amber alerts, parking violations, suspicious persons, or anything else (we have heard reports of tow truck operators using these devices to identify repos). The hot list database can either be loaded before each shift, or wireless and real time.

When the ALPR matches a license plate, the system notifies the officer, who can immediately pull over the identified vehicle. Regardless of whether there is a match, the system stores the image, license plate number, date, time, and GPS location of every passing vehicle.

Several comments have been left in response to the post, but I wouldn’t call them a discussion.  One person called the use of ALPR a search without probable cause.  Another complained about quotes in a March, 2006, Wired magazine article from Barry Steinhardt at ACLU (“There’s absolutely no bar on collecting plates in public,” and “There haven’t been any legal challenges, because it’s not illegal.”)   A recent comment ridiculed people for thinking that law enforcement agencies have “any desire to come up with schemes searching for license plate locations to attempt to `manufacture’ a potential crime where none has even been proven to exist.”

The most thoughtful comment I saw was signed by Kade, and read:

One person here argues that this technology shouldn’t be regulated because it’s no different from a cop writing down license plates and checking them against a database. If that were true there would be no reason to use this technology.

Technology changes things, and the law should follow.

Using infrared technology to “see inside” buildings is more than just cops looking at buildings, because they can’t see inside them if they just look at them. Using ALPR is more than just cops writing down license plates and checking them against a database, because no cop can write down and enter every passing plate. It’s humanly impossible.

So in the same way that the Supreme Court decided that infrared technology changes the game in Kyllo v. United States (look it up, cops), we should all kindly recognize that ALPR changes the game.

The law needs to catch up. Kudos to the ACLU for being one of the few organizations trying to keep up with the attacks on our liberty posed by accelerating technological developments.

I left the following comment:

I’m curious what, if any, protections are in place for the information gathered. Checking every license plate a squad car passes on public roads against a database of license plate numbers of stolen vehicles is quite different than building a database of when and where that squad car scanned every license plate it scanned.

Where can the public find information about how SPD’s license plate scanning system works? I’d like to read more about it.

I’d like to find out more about this.  I’ll e-mail Officer Sundin to ask where to go for more details.

A quick Web search leads me to believe that our ALPR system is from “Motorola and PIPS Technology, a Federal Signal company.”  In a September 4, 2007, press release, PIPS Technology stated:

Other cities such as Los Angeles, San Antonio, Seattle, Phoenix, Las Vegas, Chicago, and Newark have also seen success in using the PIPS Technology solution to improve their overall enforcement and investigation efforts. PIPS Technology, a Federal Signal Company, is headquartered in Knoxville, Tennessee.

Federal Signal’s Automated License Plate Recognition Investment Justification and Purchasing Guide (embedded below) contains similar text.

Also of interest from the purchasing guide (emphasis added):

In the public safety market, ALPR is currently used to identify stolen vehicle, vehicles associated with wanted individuals, vehicles with outstanding violations or taxes, and many more important applications. One of the major benefits of ALPR is the collection of data that allows for investigative purposes; this benefit is being seen with equal or even greater interest than the identification of known vehicles of interest.

Fixed location cameras operate continually, and are being deployed in known high-crime areas, or in areas with high traffic throughput such as interstate overpasses. More progressive cities such as Los Angeles, Chicago, and Cincinnati believe that an integrated mobile and fixed solution provides the greatest benefit.

A back office system software (BOSS) resides on a server in the agency, and is linked to any number of databases, or vehicle hotlists. These hotlists may reside on a network location, at an ftp location, or on a website.

As previously referenced, BOSS is also a central repository for all collected data, providing a massive intelligence database for crime investigations. Witness accounts of partial plates and vehicle descriptions may be used to locate potential suspects, suspects may be placed in the vicinity of crimes, and potential locations of suspects may be identified using historical data of where they have been seen in the past.

With interoperability and data sharing as two of the primary “buzzwords” in this market, it would be shortsighted to overlook how many agencies are now establishing linkage between their BOSS servers to expand law enforcement capability beyond their jurisdictions and improve their abilities to protect the communities they serve.

While ALPR has received the attention of privacy advocate groups, these concerns are typically short lived for a number of reasons. As ALPR removes the officer from the process of running plates, many privacy advocates and civil rights groups actually applaud ALPR as it removes all possibilities of profiling, essentially ignoring all vehicles and drivers and looking equally at all license plates. On a more straightforward note, the license plate is the property of the state as are the roadways (typically), and there is no reasonable expectation of privacy on a roadway,

The applications for ALPR are limited only by the imagination. While many of the stories in the media focus on stolen vehicle recovery, this is only one of the applications that should be considered when building an investment justification.

The data collected by the ALPR system can be maintained in the back office system software (BOSS) and provides valuable intelligence for investigative purposes…to place a suspect near the scene of a crime, to validate or disprove alibis, to find potential suspects based on eyewitness accounts with license plate data, and more. Example: Cincinnati PD was having difficulty locating a suspect in a string of copper burglaries. CPD used BOSS data to see all historical sightings of the vehicle, and were able to see a pattern, set up surveillance, and make an arrest.

Data Considerations

While concern is taken to minimize bandwidth and storage usage, ALPR systems can produce large amounts of data very quickly…especially in a public safety setting where the data is typically retained for investigative purposes. How much and how quickly depends on several variables including the data retention policy of the agency or governing legislative body, the scope of the system, and the configuration of the cameras relative to what data is being retained (license plate text only, full data set, or something in between).

Many legislative bodies will have data retention policies regarding any information collected that may be used for photographic evidence. This will often define how long an agency retains the data, and also how that data is retained (within the server application itself or on external storage). For agencies that do not have a legislative body governing this, it is common to see the data retained for 60-90 days with hits being retained for a longer period.

A rule of thumb to estimate ALPR data storage requirements is that 100,000 vehicle records equals 1GB of data.

Hopefully, in Seattle we’re not using these machines as extensively as PIPS suggests their customers do.  I don’t think our police should be tracking someone’s movement unless they have reason to suspect him of wrongdoing.  If it’s practical to have an ALPR scanner on one squad car now, slurping up the license number of every car it passes and storing that number along with information about when and where those cars were seen, it won’t be long before it’s practical to have similar machines mounted on poles at every major intersection.

Potential next steps:

  • ask Officer Sundin for guidance with requesting further information
  • ask members of City Council’s Public Safety Committee about adoption of ALPR system and any related legislation
  • request SPD data retention policy
  • request SPD ALPR procedures manual
  • request SPD ALPR usage log
  • request all ALPR records for my car’s license plate
  • request all ALPR records for someone else’s car’s license plate
  • find out how many SPD vehicles are outfitted with ALPR
  • find out if Seattle uses fixed-location ALPR cameras

Any suggestions?  Please leave a comment or e-mail me.

UPDATE 2011-02-18: Monday, I e-mailed Officer Sundin for guidance on learning about our police department’s ALPR system, asking:

Thanks again for hosting our Chamber meeting Thursday and for showing Anthony, Rachel, and me around the precinct.  When we were chatting in the lobby afterward, I asked about the unfamiliar cameras I’d seen mounted on a squad car parked outside.  You said that they’re license plate scanners used for identifying stolen vehicles — technically, cameras, but not providing images, just license plate numbers.

Being a computer geek and all around technophile whose car has been stolen and recovered (*twice* — around 2004), I’m curious about how these automated license plate recognition (ALPR) systems work and what can be accomplished with them.  Can you suggest where I could find more information, not about ALPR systems in general, but about the system used by SPD and how our police officers use it?  Among other things, I’m interested in where the list of plate numbers of interest come from, how that list reaches the plate scanners, and policies regarding logging and retention of data gathered by the machines.

I didn’t hear back from him directly, but Thursday night, I received a boilerplate e-mail about public records requests from someone else at SPD:

Date: Thu, 17 Feb 2011 21:01:45 -0800
From: Christopher Kelley <Christopher.Kelley@seattle.gov>
To: phil@mocek.org
Subject: Public request for information

Mr. Mocek,

Thanks for taking the time to inquire about  Automated License Plate Recognition.  To better accommodate your request regarding  SPD Policy and data retention, please refer to the information page on our website regarding public requests:


If you have any questions about how to obtain the requested information, please  email: spdpdr@seattle.gov

Thank you,

A/Sgt Chris Kelley
East Precinct Community Police Team
1519 12 Av Seattle, Wa 98122
Desk phone 206-733-9536
Fax 206-684-4591

This wasn’t particularly helpful, as I was already familiar with the process for requesting public records.  Directing me to a description of how to formally request a public record is not really an accommodation of my request for information that may or may not be encapsulated in some particular record.

I e-mailed Officer Sundin for advice on how to proceed with my search for information about SPD’s ALPR systems without having to file a bunch of very broad public records requests that would create lots of extra work for some unlucky public information clerk.

  5 Responses to “SPD’s use of license plate scanners: Auto theft investigation or fishing expedition?”

  1. […] This post was mentioned on Twitter by Dave Briccetti, Phil Mocek. Phil Mocek said: Do Seattle police license plate scanners store more than just plate nbrs of stolen vehicles? http://mocek.org/blog/?p=13 #alpr cc/@ACLU_WA […]

  2. I happend to know someone that was pulled over because the registered owner of the vehicle had a suspended license. Problem, he wasn’t driving, it was his wife driving who had a license. It’s bs, just like red light cameras.

    • Here’s how that scene should begin:

      Flashing lights.
      Friend’s car pulls over. Police car follows.
      Friend’s wife stops engine, locks doors, opens driver window about 5″, puts hands on steering wheel.
      Officer walks to driver-side door.
      Friends wife: “Hi, officer. Why did you pull me over?”

      How did it end?

  3. As a criminal defense attorney, I would hope that the described contact with law enforcement ended like this:

    “I’m very sorry ma’am, you see, we mistakenly stopped your vehicle because the driver license of the registered owner is suspended, giving us a reasonable suspicion to believe that the vehicle was being operated illegally. However, the RO is a male, and you are female, so I apologize for taking your time and any inconvenience the stop may have caused. Have a nice day.”

    State v. Penfield is exactly on point. (not sure the link will work here, but you can google the case title)


  4. How would the use of technology that reads a license plate that is plainly visible to everyone constitute unreasonable search? There is no entry to the property (although if the license plate scanner shows a hit , that would be reasonable grounds for a search of the vehicle in some cases).

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