Automated License Plate Recognition: An Insider’s Look

Rebecca Waters

What are some of the newest, extensive uses of this technology and how can they be best utilized?

Automated License Plate Recognition (ALPR) systems – made up of a camera or cameras, a processor and character recognition software – at their most basic are designed to capture license plate images, transform them into characters and compare the results to a database of license plates which are of interest to law enforcement. We asked six industry experts to fill us in on the state of the technology and what we can expect in the future.

“Five, or even ten, years ago, the common use in the US would undoubtedly be to recover stolen vehicles and ticket vehicles with expired license plate registrations. However, with advancements in the technology and more agencies adopting the technology, the uses of ALPR technology have grown wings…registrations and stolen vehicles are still common practice for ALPR, but so, too, are criminal investigations such as burglaries, kidnappings, homicides, and identification of trafficking patterns,” says Heather Fraser, Marketing Manager for NDI Recognition Systems.

“For law enforcement, ALPR can be broken into two categories: immediate vehicle detection and investigations,” says Peter Crary, US ALPR Operations Director for Neology’s PIPS Technology. “ALPR is very appealing for immediate vehicle detection because it allows the officer to passively monitor for wanted vehicles while performing his or her normal duties.”

When it comes to investigations, ALPR technology provides law enforcement with “an ever-increasing toolbox of analytical tools to help determine who the criminals are and where [to] find them,” he says.


The 2013 Law Enforcement Management and Administrative Statistics survey found that an estimated 17% (about 2,000) of departments used automated license plate readers, including more than three quarters of the departments serving 100,000 or more residents. ALPR technology has continued to evolve and its uses have become better understood, leading to an increase in adoption.

Some barriers still exist, with cost presenting the biggest obstacle. “Law enforcement technology is growing almost faster than [agencies’] budgets can afford. Body armor, body-worn cameras, dash cameras, fleet vehicles, operational costs…you name it and it’s vying for purchase from the same budget pool,” Fraser says.

“While the individual system cost has come down in the past five years, the solutions still remain expensive when considering the back office hardware (servers) and personnel to manage it,” says Nate Maloney, ELSAG’s VP of Marketing and Communications.  “This can be overcome by participating in a regional data sharing program that either shares infrastructure costs with the participating agencies or covers all the costs of the infrastructure outright,” he adds.

“What we are seeing is a lack of understanding as to the full value of an ALPR system,” Crary adds. “When agencies have a narrow view of the value of ALPR, seeing it as a tool for just finding stolen vehicles, for example, they will find it hard to justify. But, when we are able to convey the investigative power to an agency, the value quickly becomes apparent.”

Politics can also present an obstacle, as civilian misunderstanding of the technology has spurred some privacy concerns. “Some citizens think that the use of LPR is Big Brother watching them and tracking where they are going, but that is not true,” says Patrick O. Fox, National Sales Director for LPR and law enforcement operations for SecureWatch 24.

“The truth is, license plates exist for law enforcement identification of vehicles and are required to be visible. There is no inherent or assumed privacy in a license plate, just as anyone can walk down the street and write down a license plate number. License plates do not reveal any personally identifiable information – it is merely alphanumeric characters. The only way to link an anonymous LPR data record to personally identifiable information, like a name, address or face, is to obtain access to a state’s Department of Motor Vehicle database. Access is currently restricted to a handful of permissible purposes by a strong federal law, the Driver’s Privacy Protection Act. This Act carries stiff fines and federal prison penalties for any violation,” explains Tom Joyce, Vigilant Solutions’ Vice President of Business Development, and retired Lieutenant Commander of Detectives at NYPD.

While public misperceptions can be difficult to overcome, education can go a long way. “I’ve seen some agencies reach out to their communities, showing them the technology and educating them on the benefit which ultimately is a safer community,” says Fraser.


There are many factors to consider before purchasing an ALPR system; most importantly, your agency’s needs. “Purchasing an ALPR system without a purpose or understanding of the technology will likely lead to an underutilized system,” warns Crary. “An agency’s need for ALPR will drive the different options they may want to choose.”

“There [also] needs to be buy-in from both the command level and the individual officer level. Too often, I’ve seen systems unused because either the command or the officers using the system did not understand, or did not want to use, the technology,” Crary adds.

“Any agency considering purchasing an ALPR solution should consider the overall cost of the solution, not just the sales price,” Maloney says. “There could be a several thousand dollar difference between vendors when you take into account annual fees and maintenance costs.”

“Agencies should also review their in-house technical expertise to host and maintain the back office system. Not all agencies have the ITS support to operate and manage their own storage server. A shared regional server operated by a larger agency or a cloud-based system might be a better alternative. Finally, agencies should develop operational policies and procedures before deployment,” he adds.

“A city or police department must consider the solution’s flexibility. If they already have cameras deployed, will the ALPR solution work with them, or will they need to ‘rip and replace’ some of what is already there? If they do not already have cameras, how expensive will the cameras be that they have to buy?” suggests Kelly Haines, Director of Marketing at PlateSmart Technologies. Agencies “should be looking at the best performing LPR camera and not always the price point,” Fox says.

“Camera performance options to consider are the yield rate (the number of plates read by the camera against the total number of plates which drove past the camera), the read accuracy, closing speed performance, and low light capabilities. Agencies also need to consider whether it is feasible to mount a camera in certain places. Fixed cameras need power, communication, and a good angle for reading plates. Mobile cameras should not obstruct the patrol vehicle’s lightbar, for safety reasons, or the cameras need to be installed on other vehicle surfaces like the trunk or in a covert setting. This is where engineers and sales team[s] can really benefit an agency in determining the best setup for the agency’s needs. Agencies will want easy-to-use software which users will want to use and administrators find simple to maintain,” says Crary.

“Perhaps one of the most important [ALPR features] is the ability to easily share and receive real-time data,” says Joyce.  Plate searches, partial plate searches, year/make/model filtering, data security, and the ability to create hotlists to send and receive real-time alerts are also features to consider.

Finally, when purchasing an ALPR system, “ask for a demonstration. Ask for a T&E – make sure your team will be comfortable with the user interface. Find out if there is support both on-site and by phone,” Fraser says.

“The biggest misconception is that an agency is too small to have a system. These systems are meant to be a force multiplier,” Maloney says. “If your human capital is limited, why not allow a technology to enhance their efforts?”

Fixed Versus Mobile or Portable Cameras

One major consideration in purchasing an ALPR system is whether to invest in fixed, mobile or portable camera units or some combination thereof. All “cameras operate in the same way. They capture the image of license plates and translate them into usable data. It ultimately comes down to how the agency wants to use the systems. One agency might conclude that mobile cameras are better for interdiction because the officer can immediately spot the subject vehicle and take action. Additionally, since they are mobile and easily mounted on vehicles, they can be moved across a jurisdiction. However, they require an officer to be operating the vehicle and it is unlikely they operate 24/7, so there is downtime associated with the mobile system. On the other hand, an agency might opt for fixed cameras because they can capture all the traffic which passes a certain point in a jurisdiction 24/7, especially if they can locate the camera at a choke point. The data collected from the fixed camera is reported to a command center where they can dispatch officers or it can be directly passed along to agents in the field working on an investigation. Fixed camera deployments tend to take more thoughtful planning as there are infrastructure requirements needed to hang a camera (i.e., electricity, a hanging structure, DOT permission, etc.). A mobile camera can be installed on a vehicle in about an hour. Ideally, mobile and fixed systems should complement each other in a comprehensive ALPR solution,” notes Maloney.

Portable systems can be a good “in-between” option, Fraser says. “They do not require the permanent installation a fixed system would, but do have the read and capture capabilities of a fixed system. Additionally, they have the mobility and flexibility of a mobile system, but don’t require a human to operate. It’s also an option if an agency already has radar speed or VMS trailers and wants to just retrofit them for ALPR,” she notes.

The Future of ALPR

While cameras are expected to become smaller, more accurate and easier to deploy in the near future, the biggest advancements in the industry are likely to be to ALPR software.

“Our solutions can already recognize more than just license plate numbers; they can also detect state jurisdictions and vehicle make. In the near future, we will be adding the ability to recognize vehicle color and type,” Haines says.

“Easier ways to transform and read ‘big data’ to help identify and eradicate criminal hotspots, interrupt trafficking patterns and solve criminal cases are where more agencies are gearing,” says Fraser.

Expect to see an increase in software customization for individual agency needs, as well as increased collaboration between agencies, Maloney says.

“I believe we will see more powerful alerting and analytical tools. Law enforcement needs that ability to find a needle in haystack – that is always the goal,” says Joyce. “They need to get answers easier and faster.”

ALPR Products


ELSAG’s Plate Hunter M6 is a mobile ALPR system comprised of externally mounted digital cameras which can read plates while stationary or at highway speeds. The system compares the plate numbers to a hotlist stored on the in-car computer and automatically broadcasts hits to the patrol officer and his command center.

The Plate Hunter F2 fixed ALPR system can be mounted to bridges, overpasses and other structures to constantly monitor sensitive areas. Cameras with built-in processors, a field control unit and proprietary software capture images of license plates, crosschecking each with hotlists to identify vehicles of interest. Alarms are broadcast in real time to a command center, patrolling vehicles and/or mobile devices for immediate reaction.

The ELSAG CarSystem application monitors the activity of the ALPR cameras connected to the onboard PC. It gives the user a view of the license plates being read, alarms generated by those reads when compared against hotlists and reports the status of the system.

ELSAG’s Enterprise Operations Center manages all Plate Hunter mobile, fixed and covert ALPR cameras with features for data security, access and auditing. The EOC uploads and archives both read and alarm data coming from all of the vehicles and fixed cameras and manages the distribution of the plate database, or hotlist, to ALPR units.

NDI Recognition Systems

Engineered for mobile ALPR applications, the V-230 delivers large functionality in a small package. With its compact form and low profile, the V-230 offers a small dual sensor (infrared and color) LPR camera which is easily mountable on the lightbar, trunk lid or behind the grill of a patrol vehicle or installed elsewhere for covert applications.

The C320 Automated License Plate Recognition camera is designed for versatile operation and deployment as a fixed ALPR camera. The C320 is available with a wide range of camera and infrared illumination options offering flexibility in any fixed site ALPR application.

The Road Warrior system is a cost-effective radar (speed) or VMS (message) trailer with a full LPR system which can be deployed quickly and covertly. The Road Warrior system captures all license plate image data passing through the LPR camera’s field of view, reads it and wirelessly transmits the data and alerts the VISCE (Vehicle Intelligence Server/Communications Engine) and a variety of other assets, including patrol vehicles, handheld devices, control rooms, dispatch centers, and real-time crime centers.


The Analytic Recognition Enterprise Solution (ARES) is PlateSmart’s end-to-end enterprise Vehicle Recognition Identification analytical back-end platform. ARES uses true object recognition instead of traditional optical character recognition technology and features an open architecture which is designed to be highly scalable and integrate with any VMS or third-party software.

The ARES Viewer is a stand-alone application with an interface which allows widespread access to vehicle recognition data and alerts in real time. The ARES Viewer communicates vital information and allows you to view real-time data from anywhere, at any time, through a VPN connection to your network.

PIPS Technology (a Business of Neology, Inc.)

The P492 Fixed Wide Lane ALPR Camera is a self-illuminating, LED infrared camera, contained within a single watertight enclosure. P492’s onboard OCR reads license plates directly, independent of network or back-end system availability or workload.

The P634 Mobile ALPR Camera is a dual camera which incorporates infrared illumination for license plate imaging and a color camera to provide a vehicle overview image. Using a proprietary technique, known internally as “Triple-Flash” technology, this covert camera can effectively suppress ambient light such as headlights and bright sunlight.

The Mobile ALPR Processor SX4 simultaneously supports up to four dual (color and infrared) mobile ALPR cameras. With wireless communication, it was designed specifically for on-street law enforcement environments. In addition, an automated shutdown feature protects the processor from damage due to power surges.

Plate Alert Analytical ALPR Software features pattern management alerts. Notifications are sent when the system detects activity matching a predefined pattern which may suggest illicit activity.

SecureWatch 24

The AutoVu Sharp and SharpX are designed to provide accurate plate reads, even at high speeds, in bad weather or at poor angles.

AutoVu Patroller is the in-vehicle control interface of the AutoVu system, providing accessible features for officers onboard and allowing them to monitor incoming reads from LPR cameras.

Security Center is a unified security platform providing real-time monitoring of AutoVu events, alarm management, as well as advanced data mining and reporting capabilities. As license plate reads and hits are gathered from patrolling units in the field and from fixed AutoVu Sharp units, information is relayed to Security Center operators. In the case of fixed applications, not only can operators monitor the incoming reads from LPR cameras, but they can also view live video which is captured from the Sharp camera.

Vigilant Solutions

Vigilant Solutions’ ALPR system, LEARN, features a ruggedized and compact dual lens (infrared and color) LPR camera engineered for extreme conditions. The camera recognizes license plates in the camera’s field of view, matches against various agency hotlists and notifies law enforcement of matches. The system can also stream live video to a separate location such as a video management system.

The Target Alert Service allows for alerts from fixed camera vehicle sightings to be broadcast from LEARN to any computer or mobile device. A published Application Programming Interface (API) allows for custom applications such as gate triggering and communications with external systems.

  Formerly the Editor-in-Chief for Forensic Magazine, Rebecca Waters is a freelance writer and editor.