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It’s mid-afternoon on a Saturday as you cruise your patrol car through the parking lot of a strip mall. A small national chain store and several novelty shops offer sales to entice clientele, and the almost full parking lot shows the ads worked...

It’s mid-afternoon on a Saturday as you cruise your patrol car through the parking lot of a strip mall. A small national chain store and several novelty shops offer sales to entice clientele, and the almost full parking lot shows the ads worked. Suddenly an alert sounds. The Automated License Plate Recognition (ALPR) system has matched a vehicle it has “seen” with a database. On the screen, you see several images including the license plate of a small silver Honda parked four cars back from the entrance of the chain store. The vehicle is wanted in connection to the kidnapping of a five-year-old girl 20 miles east of your current location. You contact dispatch. “K16, that information is affirmative,” she responds. “The plate and vehicle come back positive for an Amber Alert. Standby for back-up.”

Now replace that plate number with a stolen vehicle, a wanted fugitive, a vehicle with a slew of unpaid parking tickets or one with insurance, tax or registration violations. Whatever you’re looking for an ALPR system can help you find it…fast.


What it is

In the late 1980s, the United Kingdom struggled with IRA terrorism. “The British government was looking for a means to stop some of the truck bombs being brought over from Ireland to blow up in London,” Bob Pinzler, vice president of marketing and sales at PlateScan states. “They asked the defense contractors to come up with a way of reading plates and recording them. It developed into a more general police tool.” ALPR systems are made up of several components, including the camera which can be fixed, for example on a bridge or mobile, attached to a vehicle. A system with as many as four cameras in a single unit can be utilized. The camera scans an area snapping several pictures of all the license plates, as well as images of the vehicle. It can scan an average of 7,000 to 8,000 plates during a shift. Some systems allow for GPS coordinates as well. The picture is then translated into a digital set of letters and numbers by either an Optical Character Recognition (OCR) system or a neural network. This digital translation is compared to a “hot-list”. A final component is the back office software suite, which is where the comparison list and the list of digital images is stored.

The “hot-list” is a set of data compiled from a variety of sources determined by the agency. Most utilize NCIC, their state database and information entered manually. “We get a daily text file from the Nebraska State Patrol,” explains Lincoln (Nebraska) Police Department Chief Tom Casady. The agency currently has two mobile PIPS ALPR systems. “To this we add our own parking scofflaw list and our own local wanted plates. [Everything] is automated and maintained by our information technology staff.”  

Manual information is entered as needed. The Post Falls (Idaho) Police Department’s four fixed and three mobile PIPS ALPR systems allow emergency communication operators to maintain and update the list. Along with manual input, their list is updated automatically twice daily from the state. The South Portland (Maine) Police Department also allows officers to add plates on the fly. As per their SOP, any entry made by an officer will be purged at the end of their shift.



Agencies utilize ALPR technology in a variety of ways with two main purposes: immediate interdiction and investigation. Immediate interdiction includes stolen vehicles and wanted persons. It can also be used to enforce mandatory insurance, current registration or unpaid parking tickets. Officers can immediately see a vehicle, or a person owning a particular vehicle, is wanted. After the officer verifies the information through the appropriate sources, a stop can be made. This also applies to an Amber Alert scenario or one where a BOLO has been issued. Officers do not have the capability to see and run every vehicle in their vicinity. But ALPR technology comes close to being able to do just that – making patrol efforts more efficient and effective. This technology is described as a force multiplier. “In a lot of those cases, the vehicle probably would not have come to the officer’s attention without the ALPR,” states Lieutenant Frank Clark, South Portland PD’s public information officer. “It sets the officer off to look at it.”

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