U.S. flag

An official website of the United States government, Department of Justice.

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Using License Plate Readers to Fight Crime

William A. Ford, Director, Information and Sensor Technologies Division, Office of Science and Technology, National Institute of Justice, Washington, D.C.; Meghann Tracy, Project Manager, Technology Center, International Association of Chiefs of Police, Alexandria, Va.; Dale Stockton, Program Manager, Road Runner, Automated Regional Justice Information System, San Diego; Bruce G. Taylor, Principal Research Scientist, Substance Abuse, Mental Health and Criminal Justice Systems Department, National Opinion Research Center, University of Chicago

This is a joint panel of NIJ's Office of Research and Evaluation (ORE ) and Office of Science and Technology (OST). Panelists will discuss the latest efforts to implement license plate reader technology into policing operations. OST grantees will explain various aspects of the technology and an ORE grantee from the National Opinion Research Center will present findings from a study on the use of license plate readers to combat auto theft in Arizona.

William A. Ford: Thank you all for coming to the national capital region, and you're in my home city, well, where I currently live. So I thank you for taking your time out of your day to be here. I also thank your staffs allowing you to take the time out of your day to be here.

Today's topic is license plate readers. My name is Bill Ford. I'm with the National Institute of Justice. I'm a division director with inside the Science and Technology Office.

Dr. Brett Chapman just left the room. He'll be joining us in a moment. This is a joint panel. I'm the technology geek. When you hear about mathematics, you hear about that type of work, that's where I am, and Brett is on the more social science side of the house.

And if you pardon us, need your key fob. We can either do this now, which I think would be a better time because I can talk and PowerPoint at the same time.

Brett's on the social science side, and what we've done here is … license plate readers has been a hot topic in my office for many years. And, Meghann, I apologize if I'm stealing your thunder. Several years ago … I'm invited to speak every year at the International Association of Chiefs of Police Subcommittee on Information Sharing. The chairperson of that committee, I'm amazed that she allows me to come back.

The cops challenged the government. You heard from Kris Rose earlier. We listened. The cops said, “There is this new technology out there that's coming into our place of work, and we want to use this technology, but we want to use it smarter.”

Many of you folks are probably aware of red light cameras, and they are not allowed to be used that much anymore.

We want to make sure that does not happen to this type of technology that we currently are talking on this panel about. So our first presenter — and I'm not big into reading people's bios, folks. So I'm going to tell you if you want to read their bios, take a look at the program. We got everybody's bios in time.

We are going from policy to practice to the research experiment. This is something new for us with inside the Institute. We have not done that well in the past. We are challenging ourselves to do that from now on. You will notice that we have several solicitations out there that show that, looking at the policy, looking at its operational use, getting that cops-from-the-field viewpoint for the field and then also then bringing in the researchers to look at those randomized experiments.

So, with that, I'm going to turn the table over to Ms. Meghann Tracy with the International Association of Chiefs of Police.

Meghann Tracy: All right. Good afternoon, everyone. My name is Meghann Tracy. I'm with the International Association of Chiefs of Police in our Division of State and Provincial Police.

As Bill said, at our 2007 conference, we kind of began all of this work realizing that license plate readers were here, and we actually had an opportunity to be on the front side of the technology for once. We had seen what happened with red light cameras, with CAD and RMS. We didn't want that to happen with LPR.

Just a quick note, because my presentation does contain pictures: It is not a recommendation, nor is it an endorsement by the IACP nor the United States government.

OK. So why are we doing the work that we're doing? Because license plate readers are new, there's a number of policy and operational questions. There's questions regarding privacy. Some of the early adopters received a number of requests both from the public in general and the ACLU, and they came to us saying, “How do we respond, what do we tell them and is there anything that we really need to be thinking about?” And then, of course, there are the technical questions.

Just a quick overview for LPR, for anyone who's not familiar with it: The way it works is that the cameras capture images of a vehicle as it moves into the field of view of the camera. Different vendors do this slightly differently, but, essentially, the images are then converted into an electronically readable format using a series of rather sophisticated algorithms, and then it's compared against the agency's hot list. And this hot list is nothing new. It's something that agencies have always used.

And then just some of the information that's gathered by the license plate readers: There is the time and date. Most systems now have a GPS system on them. There's also images of the vehicle. There's a black and white infrared picture as well as a color photo, and depending on the system and depending on the agency's needs and requirements, that can capture anything from just a little bit of car right around the plate all the way to the entire image of the vehicle.

For our purposes, we classified them into three categories. You have mobile, fixed and then the portable covert. And the reason for this was as we got into our work, we needed to see if there were any differences in the way they were treated in the retention schedules and the way they were used, and you can see examples of each up there.

So one of the first areas that we looked at is the policy and operational guidance for law enforcement, and this is a project that's funded by the National Institute of Justice. In addition to this project, the other way we're addressing the policy side is through a model policy, which is currently under draft, and that's supported by the IACP's Law Enforcement Information Management Section in cooperation with our policy center. Once that goes through its final review process, that will be available through our policy center.

So the Policy and Operational Guide project: We wanted to look at how LPR was being used, who's using it, what were some of the lessons learned, the success stories. Essentially, we wanted to let agencies interested in LPR know how other agencies are using it and what are some of the things that they've already run into and dealt with.

A really quick background about the project: We collected our information two ways. The first was a certified random sampling of 500 agencies for size and agency type. We took a two-phase approach, and the first phase, we initially contacted all the agencies to introduce ourselves, to tell them about the project and to find out if they were using license plate readers. If so, we wanted to know who the point of contact was, so that we could send the survey to the best individual.

And then the second phase was actually delivering the survey to those who had responded yes, those who weren't sure and those who we weren't able to contact during the first phase.

So, initially, we got a response rate of … or, initially, we got 77 agencies saying, “Yes, we're using license plate readers.” However, of those 77, only 33 were actually able to complete the survey because they, for the most part, had just started using license plate readers. They weren't far enough along to really be able to answer the questions that we were asking.

We also conducted site visits, and we went to 12 agencies, and we had a couple requirements. One was that they had to have a 12 month implementation, and the reason for that was because we wanted to go to an agency that had a somewhat mature program who had faced some of these things and who could instruct us.

And just to give you an idea, these are all the agencies between the site visits and the survey, those 77 who responded yes that are using license plate readers. You can kind of see where the clusters are, and the reason you see New York that had so many, because their Department of Criminal Justice Services is really kind of leading the way and coordinating a lot of the state effort in that case.

So what were the main reasons for using LPR? Why are agencies getting into it? Stolen vehicles is the primary reason most agencies get into it, but that's not really where the true value of license plate readers are. Their true value is in the investigator purposes. Plates can be queried by plate, the full plate, a partial plate, location and time, address within a certain radius, if it's a fixed system or even if it's a mobile system.

And, as you'll see later, it really is the investigative purpose that's really the key thing here, and the with the third most common one was traffic initiatives, and there's a couple things with this. One, when you have a traffic stop, say you set up a DUI track point, it would be kind of nice to know if the vehicle that's approaching that checkpoint is a vehicle of interest for any reason.

During one of our site visits, the agency relayed this story. The reason they began using their portable system for their checkpoints was because two years prior, during the traffic stop, it was a DUI checkpoint, seat belt checkpoint. A gang member driving into this traffic stop didn't realize it until he was well within the line of cars. There was no getting out. Instead of just going through the checkpoint, he got out and started shooting. So now they want to know if someone is coming up. If nothing else, they can begin to prepare themselves.

And the other reason is … you see the quote there from Trooper Jonathan Olsen, “The quantity of stops has gone down, but that is because the quality of stops has gone up.” This is one of my favorite quotes from all the people that we talked to because it really shows the value. He's not pulling over random person after random person. They have a very targeted program in their state.

The people that they're getting are the people that they need to be getting. They have a rather large problem with unregistered and suspended and revoked drivers, and it's caused a significant … they're the ones causing a significant amount of the accidents in their state. So they're really targeting these people. They want to get them off the road.

Some of the big lessons learned from this project: Implement and train to policy. You need to get IT involved in the beginning. It seems so obvious to all of us sitting here, but it's really one of those things where many agencies went in with the idea that this is plug and play, and it's really not. There's a lot of things that need to be considered.

The use of wild cards. Remember to check your victims. When you're setting up a mobile or a portable unit, really target your hot spots. And there's an excellent study being done by George Mason University, which is also funded by NIJ, that's looking at this.

And then, if you're setting up a fixed unit, you need to think strategically. Just because you can put a unit up someplace doesn't make it the best location. If at all possible, move to wireless update and download. Your information is only as good as the last time you updated your system.

And when you get an LPR hit, there are two things that need to happen. The first is that you need to verify that the plate image matches the plate run by the system. The systems are getting better every day; however, there is still some difficulty in determining states, and also, if you have a system, if you have a plate that's ABC1234, that 1 is going to be run as a 1, as an L and an I. And you need to verify the plate status through your dispatcher MDT.

And one of the cases that really kind of illustrates all these points is one that came out of Jefferson parish with their sheriff's office. They had an ATM business owner and servicer who, during the course of putting the money in the ATMs and doing all those things, was robbed and murdered. They had a partial description. They had a description of the vehicle; it was a green Mitsubishi with gold rocker panels. So they went to their LPR system, searched, couldn't find anything matching that description, and they didn't have a plate number.

So, as they were kind of going through and, you know, running some ideas past each other, one of the investigators had an idea: Let's run the victim's plate. That was kind of their “a-ha” moment. By running the victim's plate and running a certain number of cars and times afterwards, soon they began to notice in some of these pictures, the victim's vehicle and then a couple after, there's this green Mitsubishi with gold rocker panels.

So, from this, they were not only able to get a plate number, they were able to show that this wasn't random; it wasn't chance. They were following this gentleman, and it actually did end up leading to a conviction.

Some of the emerging issues: We're seeing a trend of the static LPR cameras merging with in-car video. It's new. We don't really know what the accuracy and the effectiveness is, and we also need to know how this will affect the standards effort. There is a proliferation of private LPR scout cars. LPR has been around for a while on the private side and on the traffic enforcement. Really, it's relatively new to law enforcement, and there is some concern of what happens when you start mixing that data. And there are some data-sharing things, which Dale will talk about in his presentation.

There was also a number of privacy concerns raised, you know, the data collection, the access, retention, is this personally identifiable information, “the police are going to be tracking me,” “everyone is going to know where I'm going.” Well, plates exist to identify a vehicle, and because of this, because of all the questions that are already being raised, we formed a working group to develop the privacy impact assessment for the utilization of license plate readers. If you're interested in this document, it is available on the IACP's website. I'm also happy to send you a hard copy if you'd like.

We released this last year at our annual conference, and it is our finding that LPR data is not personally identifiable information. There is a step that must be taken in order to connect the license plate with the registered owner's information. It doesn't happen automatically. The LPR system does not query the DMV. It does not query your health records. It does not query anything else other than the list of plates that it is put into the system.

It may seem kind of funny that I say health records. Well, up in Maine, there was earlier this year some back and forth where the legislature was looking to ban license plate readers, and in the conversations that they had had with the legislators, they actually did think that it was going to query all of these databases. That's simply not the case. In order for that connection to be made, you must still do the investigative work.

At the time that we developed the PR report, there were no court cases. Recently, a decision in U.S. v. Wilcox came down that addresses this issue. The defense claimed that the LPR invaded the defendant's privacy interests. Wilcox was driving down the road, committed a vehicle infraction. His plate was run by the two officers driving. It came back as not belonging to that vehicle, so they pulled him over. Upon a driver's license check, they found that Wilcox had an outstanding warrant against him, arrested him. During … as they were searching through his vehicle and searching through his person, they found a couple of firearms on him, and he then had another charge added. Obviously, felons aren't supposed to have firearms; at least in Georgia they're not.

And so he said, “No. You need to throw this all out. The LPR violated my privacy. If the cop had looked with his eyes, it would have been different, but because he was using technology, it's a violation.”

The court said, “No. There is no Fourth Amendment protection. The law requires a plate display. In fact, it is the state that gives you the right to drive on a road. It is the state that requires a plate be displayed, and be displayed at night with that little light that illuminates it for the purposes of identifying that vehicle. And this has been around long before license plate readers came into being,” and they cited the rulings from the 5th, 6th, 8th, 9th and 10th Circuits. And, really, they noted that LPR is not a technology that invades privacy like thermal imaging, which is what the defense was claiming.

A couple of additional resources. I mentioned the standards effort earlier. The IACP has received funding from NIJ to help them in the standards development process. This is actually a three-phase project. Currently under way are the in-car video standards. Following that will be the interview room recorders. The third and final phase will be license plate readers.

There's also regional training that's being provided by the IACP to the TTAP project, which is a great training on the policy side, and then there is, as I mentioned, the George Mason study and the work that my co-presenters are doing.

There is a portal now available on the George Mason website. I am sure Bill can tell you more about that.

Please feel free to contact me if you have any questions, if you have any stories to share. We're doing a lot of work on the policy side, and I'm happy to talk more at length about it. There's a lot going on.

So now I'd turn it over to Dale.

Dale Stockton: Good afternoon. I'm Dale Stockton. I work with the Automated Regional Justice Information System in San Diego, and by way of introduction, I spent more than 30 years carrying a badge and a gun, so I'm definitely the practitioner side of this. I'm not a technologist, but I have to tell you as an up front this is the best tool we've had come along in a very long time. It can really impact crime. It can really impact public safety, and I want to share from a practitioner perspective how this is all beginning to come together in the field.

Briefly, as introduction, license plate readers today — and it wasn't always this way — but they're much more effective and they can actually capture a plate at a closure speed of 150 miles an hour; in other words, two cars coming at each other, that plate reader is able to pick out that plate and check it. And although it's often obtained for using for fighting stolen cars, the reality is we're beginning to understand that the value goes far beyond stolen cars, particularly in the area of investigative support, but it can also be used to check any database; for instance, your local registered sex offenders.

Now, it's important to realize, though, that the checks are being made against a static database, not a live database, because the reality of LPR is it can run thousands of checks in a day, one unit can, and if we were to be doing that against a live database, such as shipping it through inlets, it would literally bring the system down. So you're only as good as your last download of information.

Now, once that plate is read, that plate is retained, and assuming the agency stores the data, it can later be subject to a query for investigative purposes. The biggest reason that we want to use LPR in the field, though, is that it truly is a force multiplier. Officers can do their normal job on patrol, and that license plate reader unit can function in the background while the officer can pay attention to what's going on around them.

Now, what we know is that a good officer, a very proficient officer, can usually do somewhere in the neighborhood of 100 to 150 checks in a day if they actually can dedicate themselves to that in addition to the regular patrol duties. A license plate reader can do 5,000 checks, a lot of variations depending on how much traffic is going by and the speed of the vehicles, but suffice to say thousands can be done in a day with a license plate reader.

And, as Meghann mentioned, the value of the data is that it provides you with a photo, a time and date stamp, and a GPS location of where that plate was seen. So, when you start thinking about how that plate can be used, the investigative value is really at the top of the list. It also helps you when you're trying to find somebody, not only suspects, but perhaps a witness that has drifted off the radar for whatever reason and is essential to a trial, you can look and see where that person's vehicle was last seen, and that gives you a place to start.

One of the more recently realized applications is in support of homeland security because, around this country, we have identified infrastructure that we know is at risk, and one thing about that infrastructure: It's not moving around. So, if we start looking at vehicles frequenting that infrastructure, that can give us greater insight as to where potential risks are.

And the way I like to put it is, essentially, you can tell which vehicle is where, when. Notice that's a retrospective look, which vehicle was where, when. Give you a real-life example: Escondido, California; this is an agency in northern San Diego County. They had a hit-and-run case. It was a fatal with a pedestrian. They didn't have a lot of information. All the witness could say is a partial plate and a gray Ford Taurus.

Now, in California, those three missing letters would equate to thousands and thousands of possibilities, and quite frankly, with DMV, it just wasn't of any use. They checked some normal resources and they couldn't come up with anything, and the interesting thing about Escondido was they had one LPR unit, a single LPR unit on a car, and they had only been using it for a very few months.

The unit was originally obtained for the purpose of finding stolen cars. So a couple of officers, shortly after they got the unit, got the permission of a supervisor, and they came in. They were going to catch the big one. They wanted an occupied stolen. They got the LPR car. They go up and down every street in town all day, and at the end of the day, they had gotten absolutely nothing. And they are pretty, pretty disappointed about it. To be candid with you, they felt like, “Gee, you know, this thing didn't work.”

Well, unbeknownst to them, what they had done was they had captured an LPR read on a gray Ford Taurus with that plate, and that's the actual capture there. The picture is not real clear, but trust me, that's a gray Ford Taurus, and they had the full plate number on it. And, of course, with an LPR capture, they were able to map it, and that mapping led to the officers going out, checking the area, subsequently finding the vehicle and the guy actually working on the car, trying to repair the damage. So those officers that had diligently worked their town looking for a stolen car had unknowingly solved a crime that wasn't going to occur for another three months.

Now, like most data, the value is when you can look at it on a larger scale, and to do that with LPR, we've really got to share the data. That's really the key to making it happen. This is just beginning to happen around the country, but it needs to happen a lot more. I'm a big, big proponent of this, and without it, we simply have information silos sitting around different agencies, and the value to individual agencies within just their jurisdiction is really limited.

So the key here is linking agency reps early and linking them often and having them share the information, and ideally, you'd have those agencies sharing data because not only does it give them a more effective alert and analysis of the data, but it lets them have some degree of economy of scale when they go to make purchases. It also gives them better vendor support, and what we found is that lessons in one agency are usually applicable to another. The learning curve on LPR is not real steep, but certainly by learning from others, you can get there a lot more quickly.

And then, finally, if it's suitable for the region, you can even share infrastructure, such as a server where data can be pooled and queried by multiple agencies, and I will give you an example of that here in just a minute.

In the San Diego region, which is the area I am primarily familiar with, we have both mobile — well, I won't say both. We have mobile LPR, we have portable LPR, and we have fixed LPR, and those are the agencies that are currently using those different types of license plate readers; however, in spite of the Regional Justice Information System, RJIS, and our long history of sharing data among the agencies, when it came to license plate readers, it was unique to each agency. We were creating our own information silos.

So, as a result, they were each holding their own data, and virtually no sharing was going on. When we looked at that, we just said, “This is not the way we do business in this region,” and we wanted to do it differently, and the solution we came up with was a regional server.

So, in making that decision, we considered, you know, what would be the advantages, and certainly one of them was by providing that data storage. License plate readers generate a huge amount of data, and if you don't have significant IT infrastructure, it can overwhelm you pretty quickly.

It also, obviously, facilitates the sharing of the data. You're pooling a much broader region, and you have a better grasp of what's happening in your area, where those vehicles can be located.

It permits query by non-LPR-using agencies, and this is one that's often overlooked, but it's really important. I want to emphasize this. There's a lot of agencies. You see those patches down at the bottom. Well, those are the agencies in San Diego County that have marked patrol units and do typical municipal policing-type functions, but RJIS has 82 member agencies. So, within the San Diego region, there are 82 justice-related agencies that would really like to have access to that data, and because they don't have license plate reader systems, absent a regional server, they don't have it. By building a regional server, we give them access to that data.

It also provides the storage option for new LPR agencies. So an agency that's looking to get into license plate readers can dedicate more of the money towards the hardware that obtains the image as opposed to building the IT infrastructure that's necessary to store the data.

This type of approach also supports a regional alerting function and encourages agencies to develop a regional hit list, hot list, alert list, whatever you want to call it.

And finally, longer term, it gives you an infrastructure on which to build. We are building out our system. We have just started with fixed. We have two license plate readers that are fixed in the county currently. We'll be adding another two dozen, maybe three dozen by the end of next year. Now, fixed readers generate a huge amount of data, and absent that regional server, I'm not quite sure what we would be doing with the data.

So the status of our project: As of now, we've got the regional server. We got the regional server as a result of a stalled federal project, but, unfortunately, when we started we had no software to handle the data. And then came along NIJ with a project they'd been working on. They funded SPAWAR Charleston to develop a standards-facilitating software. It's called LPRD for LPR data, and Mr. Ford, bless his heart, agreed to let us use that software to support a regional server, and it's working. The intent was to provide for support for both a multi agency and a multi vendor effort.

As far as I know, this hadn't been done anywhere in the country, to combine both supporting multi-agencies and to be vendor agnostic, and as of today, it's operational with three agencies. We are adding more. We wanted to mature the software a little bit and make sure that it was as stable as could be, and it's also working with multiple vendors. Currently, the software works with ELSAG, NDI, PIPS, PlateScan, and we hope soon it will be working with AutoVu. Now, if your favorite vendor isn't listed there, I'd encourage you to encourage them to find out about the standards effort, because one of the things we heard from the vendors at the front end was, “Well, if the customers ask for it, then we'll do it,” so they need to hear it from you. And along the way we've tried to encourage them by noting that law enforcement will be looking at these standards when they go forward in terms of grant purchases.

So, in terms of giving you a visual on it, in San Diego, in essence, what we have is multiple agencies feeding into a centralized regional server, and by so doing, each agency can retain its own data, setting its own retention standards, and they're not limited to one brand of license plate reader to buy.

Additionally, because of the access to the data by non-LPR-using agencies, any RJIS member can query the data, and if you're wondering what kind of agency that might be, it could be probation, it could be a district attorney investigator's office, social services. There are a number of agencies that benefit from criminal justice data.

Now, let's take a look at a different approach. I'm not going to say this one is better or worse. It's different, and it's significant that we look at different systems because the reality is we've got different systems springing up all over the country. This is the Los Angeles approach. They've got more than 25 agencies; they're sharing, just beginning to share data now.

Now, their data is able to be shared because they're using one vendor, and that vendor facilitates a Web query-type sharing, and each agency in that case is holding its own data. You're relying on those agencies to retain the data for you to be able to access it, but for them, it's working. And it depends on where you are in the rollout cycle, which approach might be better for you, but my thought was, well, we want a system of systems; we want to be able to share with San Diego, between San Diego and Los Angeles, and we have been actively discussing this with them to make that happen. We want our agencies to be able to query L.A. data and, conversely, L.A. agencies to be able to query San Diego data.

Now, what's important about this is that we have a system of standards, because if the data isn't in some type of mean compliant Global Justice XML standard, we are not going to be able to make that happen. And vendors, bless their hearts, they bring out their products, and they tend to be somewhat proprietary. They want you to buy more of what they have to sell, understandably, but so far, the cooperation level on the part of the vendors has been pretty good, and they are moving forward with the idea that standardized data will be something they'll support.

So, as we go forward on this, I showed you the L.A. and the San Diego thought, but there is a great deal of discussion around how do we do this on a national basis, what are we going to be looking at as we move forward, and specifically, we believe — I believe — and there are some people that are working on this with me — that the key here is we develop regions around the country.

We're probably not going to have any centralized national giant bucket of license plate reader data. It probably wouldn't stand the court of public opinion, and it's probably something that given where we are in the rollout cycle wouldn't easily be done, but we can develop regional sharing capability, such as the San Diego effort and the L.A. effort I showed you.

And so doing, you get those set up and then begin to share between those regions, and as you begin to look beyond your region, utilize a trusted broker like Nlets, and if you're not familiar with Nlets, they have a booth set up at the front. I'd encourage you to check with them, but they're a trusted broker. Every law enforcement agency has a connection to Nlets. Nlets would serve not as a storage unit but as a pointer system, something akin to a Google, so that when you check a plate, Nlets would point you in the direction of where that plate can be found, and the result of that would be a query in one state by an investigator could give an indication of plates of interest in other states, and then that information can be pulled back.

Now, we're not there yet. We're not anywhere close to that yet, and yet we're standing up these systems. So I strongly encourage anyone involved in LPR in the interim to establish an e mail group and do an e mail blast when you have a vehicle of interest. This is working in the southwest area of the United States. I've seen these go out on average about once every two weeks where an agency has a high-profile crime, sends out their e mail list, and several times, within just an hour or so, will have a significant lead on a vehicle that they're looking for. It does work.

One of the questions about license plate readers is this kind of hocus pocus, “you are invading my privacy; it's super intrusive.” And I come from the opposite end of the spectrum. I truly believe that this technology is only doing what license plate readers have already — I'm sorry — what officers have already been doing in the field for many, many years.

The courts have indicated to us that officers can look at a plate and run it. So let's just go down quickly here through the two sides, an officer doing it and the license plate reader doing it. Officers can run plates anytime they want. The courts have held that's why we put the state plate on there, so an officer can check and make sure it's current and it's not wanted. Well, the license plate reader is doing the exact same thing. It's looking at it; it's checking that plate to see if it's wanted. The officer can pick and choose among the vehicles that he or she looks at.

Now, this is an interesting differentiation because license plate readers, on the other hand, they don't differentiate. Some people would say they're not biased, and to any of you concerned about any type of bias-based policing, license plate readers are absolutely the antithesis to racial profiling. They don't care what color you are, what color your car is. They're picking up all those plates.

The officer can write down and record that info, and officers frequently do when they see something a little out of the norm. They'll jot it down, jot the time down, and that's what a license plate reader is doing all the time, noting time, date and location.

The officer can hold onto that info, and they do with their memo pad until such time as a detective comes down to briefing and says, “Hey, does anybody have anything on this type of information?” And, of course, the LPR reader is also holding that data.

An officer can provide that information to an investigator upon request, and a license plate reader can be queried for that same information. Past information may be very relevant to a crime later discovered; in other words, “Yeah, I saw this three days ago, and maybe it's something you're looking for.” And obviously, the license plate reader can provide that same retrospective look.

Now, the difference is on the officer's side, there's a weakness. The officer has to remember it, write it down, has to be aware of the request and then able to provide it to the investigator. So let's change gears here for a minute. I want to provide you with some of the myths in LPR and dispel them.

Specifically, “my vendor is best.” There's several good vendors out there, probably half a dozen major players, and it really depends on your needs, and I always ask people what's the area you're in, already using. That always helps.

“LPRs are primarily for finding stolen cars.” We've already seen examples of where that's not the case. We're certainly getting beyond that.

“They take the human element out of policing.” One of the things we often counsel people about is you can't depend on the information that just pops up on your screen. It's not a death ray. You have to confirm the information and take appropriate action like any responsible officer.

“They target people unfairly.” Well, as I just mentioned to you, they're absolutely color-blind when it comes to plates and cars and people. They pick up everything.

“They are too expensive for small agencies.” The good news is the price is coming down. The officer activity … you'll hear about that in the next presentation, but suffice to say, it's truly a force multiplier.

Here is one: “The accuracy rate is this big.” And this is primarily a vendor-driven thing. I'll give you this quick example. They'll give you a number, 95 percent accuracy. Well, here's what you need to ask to be an informed consumer. It's what's the capture rate, what's the accuracy rate. And I know we have a lot of academicians here. Here's a quick example: 100 cars in a parking lot; 50 of them get read; 49 of them get read correctly. To a vendor, that's a 98 percent accuracy rate. That's not 98 percent to me, but to a vendor, that's 98 percent because of those 49 it got right, 49 out of 50, that's 98 percent. Well, I'm thinking 49 out of 100.

“My cameras read all 50 states.” The reality is cameras have to be configured for the region of the country that you're in, and while they may be able to be configured for all 50 states, don't let them tell you they'll read all 50 states as if 50 different states could go by and it will differentiate between them.

The hot lists are only as good as you make them. The alerts are in need of being updated frequently, and as Meghann said earlier, wireless uploads, real-time uploads are important.

This one is going around a lot now. “If you have got an old computer, just add a camera and you're good to go.” It's a lot more than that. The algorithms are important, and watch at the next IACP show. You'll see some brand-new vendors.

Bottom line: Do your homework. Make sure the vendor has some experience in your area.

I've got some tips for you, again, from these trips we made around the country. I have to go through them quickly in the interests of time, but, first of all, wild cards, very, very important, and I got to give you this story to show you the importance of it.

More than 30 rapes in three years in an area of Florida; the suspect would choke his victims into unconsciousness before he left. As a result, there was no vehicle information until they finally had a break where a victim was able to give a partial plate. The analyst in this with just that partial plate, even though one of the numbers was wrong, was able to get a suspect vehicle in a matter of minutes.

They used that information. They set up surveillance, and they actually targeted the guy, apprehended the guy as he was in the process of going after another victim. So remember Victimology 101. Meghann told you the story about Jefferson Parish; that's a great example, you know, where was your victim. It's not just where the suspect is; it's where the victims are.

Hot list, clear instructions as to what to do. Hot lists need to be updated. The more frequent you can do it, the better. Real time is key. Share, share, share to be effective. The broader perspective you have, the better. Hot spots, hit them relentlessly before, during and after an event, because if you have something go wrong, you'll have a resource of information to go back to in terms of people to look at. You might just bust an alibi.

Utilize wireless upload or download, if possible. Many agencies are still using USB, but cellular makes a great backhaul to do this.

Accuracy in time, accuracy of both time and GPS data. This is a new evolving issue I don't have time to get into sufficiently now, but suffice to say, the time and the date and the location stamp have to be accurate on that LPR read if we're going to utilize it in any type of investigative endeavor.

Keep the LPR in the field. If it's not in the field, it's not capturing LPR information; it's useless. So think about that when you are assigning the units.

And finally, registration enforcement. It's time for a new perspective. We've got to put an emphasis on getting those plates displayed cleanly, so the LPRs can read them.

Maybe I have one more on here. Yep. This is a freebie. If you have LPR units, don't run them through the automatic car washes because over time, guess what, the camera doesn't point in the right direction.

That concludes my presentation. That is my contact information.


Bruce G. Taylor: Well, good afternoon. I'm going to discuss an experimental evaluation that the Police Executive Research Forum conducted. When I was the research director at PERF, I led this study. I had two colleagues, Chris Koper and Dan Woods from PERF, as well on the project.

I'm with a different organization now, the National Opinion Research Center, but I was the principal investigator for it, so I was asked to come and talk about the study, and I'm happy to do that.

OK. There were two phases to our study, and I'm going to be focusing mainly on phase one because we really won't have enough time to get to phase two, but, basically, phase one was with 117 what we called the “hot routes” of where we thought there would be active, sort of cars moving about that had been stolen. And I'll talk a little bit about how we came up with that term and how we defined these hot routes.

And then a second study was building on the first experiment, on things we learned. We designed a second experiment where we focused on a smaller number of routes. We worked with about half those number of — not the same routes but a different set of half of those routes where there were larger areas, and we did some similar experimentation.

I'm going to be reporting mostly on … today on some simple bivariate results, just some cross-tabs and some simple frequencies, but these results were confirmed with more complex modeling techniques. But I found the results were basically the same, and it's easier just to present some of the simple, straightforward percentages.

OK. So the first phase was a six-month experimental evaluation. Just by way of background with the experiment, I mean, generally, in the social sciences we consider the randomized experiments sort of the gold standard, you know, because we were able to sort of have equivalence between the treatment and comparison groups and be able to sort of isolate what the effects are, and that was our thought here. I'd been involved in a number of experimental evaluations in policing. I thought, “Ooh, well, this is an interesting piece of equipment,” didn't know a whole lot about it, had to learn a lot about it, but I thought, “Let's see if this sort of equipment can hold up to sort of the, you know, rigorous evaluation and see what kind of effects we might get from the equipment.”

So what we did was we identified … we were in Mesa, Arizona, and at the time, Mesa was in the top 10 for auto theft in the U.S., and so we thought, well, that's a good place; there will be a lot of activity for us to look at. And what we were able to do was we were able to identify 117 routes, hot theft auto routes. And, basically, what we did was we worked with a geographer to look at where the cars were stolen and where they were discovered, and she had a very interesting geographical spatial analytic method to connect those two dots. And it's more complex than I'm describing, but, basically, that's what she did.

And what we did was we identified a whole series of routes, but rather than relying just on the math, we also wanted to talk to detectives as well, and people who had been working the streets about where the routes were. I mean, sometimes the official information would be missing some other things that are going to happen in the study. So we identified an additional set of routes. A third of them came from talking with the detectives and officers.

And the idea there was that we we'd get a little more buy-in from the study where people thought they were contributing. So, basically, you get these 117 routes. You put them in a big hopper, and then you randomly assign them to different conditions. Now, just in general, these routes were about a mile in length, a mixture of residential and business areas, some highways.

We also had the officers grade each of those routes by ease of surveillance — were there nice places you could hide to put the equipment, or were there certain sort of difficulties with it, like if you have a … Mesa has got six-lane highways. They're really big. Those tend to be more difficult to set up because cars are going by real fast, and you can only cover so many lanes with the equipment.

OK. So we assigned the three conditions. Mesa had an auto theft unit that they had been using. This was a small spot of specialists who knew a lot about auto theft and been working these type of cases for a while. There were five people in the unit. And what we did was we wanted to look at how this unit used the equipment, and we wanted to use it when they didn't use the equipment, but we also wanted to have under normal patrol conditions.

So these would be … the auto theft unit, that's all they did. They didn't take calls for service. They would just focus on auto theft, and they would run out there and just be looking for auto theft. The question was, well, what happens when you give this unit this equipment, do they get better, or what happens when you have them just do standard sort of manual checking of license plates.

Then, we said, OK, we also wanted to compare that to what happens when you don't have a special unit, you just had standard manual checking of the plates, and notice how we set up the day. What we did was each route we assigned to get about an hour of sort of intense surveillance every day for two weeks. And what we did was the LPR team, they would have a route assigned to them, and then they would also have assigned to them, the same group of four officers would also have assigned another set of routes, which they wouldn't use the equipment, and they literally would turn all the equipment off.

We did some audited checking to make sure that was happening, and we had ways also with the LPR equipment you could tell if it's scanning, so that's not much of a problem. We could check to see that they were following the study design, and the officers were terrific, and really, you know, we explained the study and why we were doing it. I think it made perfect sense to them why we were doing what we were doing.

OK. Next piece to it. I'm not going to go into these advantages and disadvantages. We heard a lot about that already, so I'm going to move on.

Just to give you an idea of the geographic now, this is the city of Mesa. It's kind of hard to see there, but, basically, you can imagine … and you can see in the western part of the city is where a lot of the hot spots turn out to be, and, you know, so a lot of the routes end up being there, but they're all at least a mile in length.

OK. So, just in terms of the general tactics, what the officers would do is they would … when they used the LPR equipment, they had a route. They would first do an initial sweep of the area. They'd have the equipment. They'd check every little parking lot there was, every little apartment complex, run the roads, and just do an initial sweep of the area, and then they would try to identify, based on their experience, where a good place was to set up, and that way, you can get your maximum number of cars coming by, you know, going by. And they would pick those points, and they would move them during that hour if they needed to.

And there also was a supervisor involved who they would confer with in terms of what they were doing. Actually, I breezed by the other slide. Just so people know, there's a team of four officers that were working these cases, two marked cars, two unmarked cars, so you had four officers dedicated to a one-mile spot for an hour, every day for two weeks. You know, that's a pretty intense effort, and it's a pretty heavy commitment of resources by the Mesa Police Department to do the study.

Now, just in terms of any time you look at a randomized experiment, one of the questions comes up was did the experiment work; I mean, did you have equivalence between the treatment and the control groups. Well, yeah, we did. So, when we looked at … once we did the assignment, there were no differences in the groups in terms of what we said, pre treatment differences, the length of the routes, the speed limits; all those things were equivalent, number of arrests that were going on. There was just a whole range of things we were able to get equivalence through the experimental design.

OK. So what did we find? OK. First, not surprisingly, you know, the LPR leads to significantly more checks, about eight times the number of checks, and we had talked before this meeting, I think some of the estimates that had come up, some of the work may have been 20 times the number, but I think some of that has to do with probably where you set up, the kind of routes, the level of activity in cars. I think, maybe optimally, if you had a lot of cars flying by you, you could get maybe 20 times the number, but in our study, anyway, it was eight times the number. It was a still lot more checking than … and also, the other thing that it's important to keep in mind is that the officers who were doing the manual check were doing a lot of checks. I mean, that's all they were doing. They weren't answering calls. So they were just typing away. So you can type a lot, too, if you have people who are working hard. They can do a lot of typing, too. So we didn't find, you know, quite the 20 percent difference, but a lot more checks were done with the LPR equipment.

OK. The other thing we found was there were significantly more hits, so stolen car hits, stolen plate hits, other hits, total hits. We found that the LPR would give you more than the manual checks, and that was what we wanted to see.

OK. Also, we found more arrests as well. There was significantly more arrests than the manual checks for stolen car arrests and total arrests.

OK. The LPR leads to significantly more occupied stolen recoveries than the manual checks. So that was one of the things, of course, the officers were real interested in is they want to get a live body rather than just finding a car parked on the side of the street. So this equipment seemed to be helping with that as well during this time frame, so that's good news.

What we didn't find, at least in phase one, was we found no differences when you look at crime reporting through the UCR and calls for service. So you take these routes and you look at them across those three groups, the control group, the LPR route and the manual route, the control route being just standard patrol; we didn't find any differences. So we didn't affect the actual auto theft rates on those routes in the first phase.

Now, I'm not going to talk about the second phase, but in the second phase, we actually did find some differences that the LPR route did reduce the crime rate, so that was kind of interesting to see, but it was a little bit of a different approach that we took. But, in any event, we didn't find that here.

OK. Next thing. There were, however, less auto thefts during two weeks post period for routes with the manual checks compared to both the control routes and the LPR route. So, if you look at the far right side, the .05 and .08, at least on the … let's see. On the first one to the left, the UCR, the auto theft rates, there were differences for the LPR route versus the manual route. Then there were also differences on the ones that write the calls for service where we had the manual rate lower than both the control and the LPR routes. So that was kind of a puzzling finding. We said, well, why would manual checking lead to reductions in auto theft? We got a little bit of theory behind that, why we think that might have been.

No differences across the groups in all crime types during the intervention week. So this is where, instead of looking at just auto theft, we looked at other crimes that were occurring, all crimes, didn't find any differences there with the equipment, not that you necessarily would expect that, but we didn't find that, neither for the calls for services, for any calls as well.

Just a couple of notes about limitations about the study: Any time you do this kind of experimental work, it's important to recognize that we, you know, created somewhat artificial conditions was we told the officers you can only be on this route for this hour, and you had to move along the way we said, you know, and that's not how they work, of course. They'd much like to roam a much larger area. So the officers did feel a little constrained.

Now, the officers understood the study, and as far as we could tell from all the auditing we did that they stuck to what they were told to do. They were good soldiers, but, nonetheless, you know, I think that does go a little against what you would expect. So that might have, you know, in some ways, sort of constrained what the benefits you might see from the LPR because they weren't using it exactly how they would use it, but we needed to confine the study in this way to do this in an experimental way.

Also, we had 117 routes, which is a pretty big sample in this world of doing sort of hot spot policing, but, nonetheless, you know, it is a relatively small sample in the scheme of things. I mean, there's other studies done in criminal justice where you may have hundreds of cases that you look at, and we only had 117. So that limited the statistical power a little bit. So that's a limitation of the study.

LPR, I think, was only recently introduced to the agency. They had been working with it for more than a year, but, nonetheless, you know, the officers who were using the equipment had a fairly limited experience with it, and we gave them some pilot period to warm up to it. But, you know, I mean, it's safe to say that over time they are going to get it. The agencies are going to learn and they are going to get better with the equipment over time; whereas, the manual checking, well, they all had already been doing that for dozens for years. These officers already all had 10 or more years' experience, so they had a lot of experience with that. So there was some adjustment.

Also, Mesa, Arizona, you know, can run up to like 120 degrees in heat. I know when I was out there, it reached that, and, you know, this equipment, you know, held up pretty well, but there were times when they ran into some equipment failure-type issues that they had to bring in for service, and I think some of that we understood may have been heat related, so there may have been a little bit of down time during this.

I think also, you know, we noticed that there's probably a need for new technological advances. As Dale mentioned, you know, it doesn't scan every plate it sees, which, being a novice to this area of LPR equipment, I thought, “Wow! Doesn't it scan?” No, it doesn't, and I don't know the exact number of scans, what the percentages are, but maybe it's about half it scans or so or depending on the equipment?

Audience Member 1: It's on how many variations you see.

Taylor: Right. So it's probably on the context, lighting conditions, maybe a variety of things that kind of affect it, but that's an important thing.

Now, I would assume over time that the technology is going to get better. So, as the technology gets better, you read more plates. You know, the results may be better. So those are just a couple of things. You know, it doesn't handle multiple lanes very well. I mean, you know, basically, the officers … I think the manufacturer, this was the Remington equipment. I can get people the exact model number, if you're interested in it, but they had told us it could read like four or five lanes. And, no, it doesn't do that. You know, I think they were pretty comfortable with about two lanes in, and even that, there were, you know, real implications with it. You know, if you're on a highway and you've got someone flying by you at 80 miles an hour and you're in a standstill, it's kind of tough to go catch up to them, especially someone who wants to get away; at least, that's what the officers told us.

So there were cases where there were safety issues where the officers didn't feel they could confidently go catch some of these people, but they'll get better with those equipment. They'll come up with better strategies. Maybe they'll be setting up barricades and other things in the future, but they weren't going to do that here in this particular case. So I think that's just some limitations that are worth saying.

And just a couple of summaries of our findings: So, we found a whole lot more plate scanning that you did with the LPR equipment compared to manual checking. The LPR was associated with more positive scans for auto theft than manual checking for auto theft and stolen plates, more arrests as well. So that's all good news. Unexpectedly, as I mentioned, we found that the manual checking was associated with less auto theft two weeks post intervention than the control group, and we found no evidence of crime displacement as well.

So just a couple of notes here. I know I'm kind of running out of time here. I think these are some of the implications of our findings is that a specialized auto theft unit conducting intense manual checking is associated with lower auto theft compared to standard patrol, shows less frequent plate checking. So I think that's good news, and that when you do broad-based license plate checking, there is some value to that, regardless of how you're doing it, with a manual checking or you're doing it with the equipment. So that's one of the things we did find.

I think what the trick's going to be is to figure out some modifications in the strategies. I mean, one idea that we sort of kicked around about why the manual checking reduced auto theft in this case and the LPR equipment didn't was just how you're using the LPR equipment compared to how you're doing the manual checking.

The manual checking, basically, what you had to do was you had to travel with traffic to do a lot of plate reading, but just sit on the side of the road, pretty tough to read plates as they come flying by, so you have got to do that. And you create a little more visible of a presence; whereas, while we did that initial sweep with the LPR equipment, we'd basically set up in a place that you can kind of hide, so the bad guys hopefully wouldn't see you and they won't redirect around some other way.

But I think what happened is that the manual checking, when they're doing the manual checking on those routes, they probably created a greater presence potentially in those areas, and that greater presence might have actually helped reduce auto theft in those particular routes. I mean, that was one idea we had talked about with detectives, some of the officers, and we have to think about it some more, and we have those phase two results that we've also been analyzing as well, and that may help yield a little bit there.

But one idea that came out was that we might need to think of some new strategies, and one of them was that if you have the LPR equipment, you know, there may be ways that you may want to be a little more visible in some cases with the equipment. They really were focused on real covert sort of activity with the LPR. Maybe that's not the best thing to do, and there may be more of a mixing of the manual checking with the standard scanning. There's no reason why the officers couldn't have the scanning going and doing other stuff at the time, I suppose, and that was one of the things they started thinking about was just sort of observing their settings around them and other kinds of strategies. And it's real interesting to hear what the other two studies and they're already thinking about a lot of that stuff, and I think as we move forward, this kind of work, it's something to think about, some revised strategy to enhance maybe some of the auto theft reduction capabilities of the equipment.

I pretty much hit that. So I think I'm basically out of time. I will go ahead and wrap up. I'm not going to really have time to go to phase two. So we'll go ahead and wrap it up right there.

Date Created: August 9, 2019