How Do License Plate Readers Work? A Comprehensive Guide

Automated License Plate Readers: How Do They Work? | gtechna
February 12, 2024
How Do License Plate Readers Work? A Comprehensive Guide

There's no mystery or secrecy involved — License Plate Readers (LPRs) use cutting-edge technology to recognize, process, and match license plate data to trigger workflows.

Public and personal information remains protected, and no hidden risks are associated with LPR in parking enforcement and management. Here's what you need to know.

What are Automated License Plate Readers?

Automated License Plate Readers (ALPRs) are digital "detective eyes" constantly scanning and decoding license plates. 

An automated license plate reader can be: 

  • Fixed — mounted on poles, traffic lights, or buildings
  • "On wheels" —integrated into patrol cars

These camera systems, consisting of one or more cameras, use artificial intelligence to translate the alphanumeric codes of license plates into actionable insights.

They silently and efficiently survey their surroundings, following clear instructions. When they detect license plates that bear significance—a vehicle reported as stolen or an offender of parking regulations—they send this information to the relevant authorities by triggering predefined, automated workflows.

This technology has revolutionized the landscape of parking and law enforcement, offering outstanding efficiency and effectiveness compared to traditional methods. Traditional approaches often relied on manual patrols, chalking tires, and periodic checks. On the other hand, LPR technology automates the identification and tracking of parked vehicles in real-time. This results in a more proactive enforcement system, significantly reducing the need for physical patrols and minimizing the likelihood of overlooking violations.

The speed and accuracy with which LPR systems can scan and process license plate data translate into streamlined operations, expediting the identification of infringements and optimizing the allocation of enforcement resources.

How Do License Plate Readers Work?

  1. When a vehicle passes in front of an LPR camera or the mobile LPR car identifies a vehicle, the system takes a high-resolution photo of the car and its license plate. The camera is equipped with specialized optics and lighting to enhance image quality and capture plates effectively, regardless of the lighting conditions. 
  2. The captured images are processed to isolate the license plate and extract the alphanumeric characters. The algorithms will enhance the appearance, correct for distortion, and filter out any irrelevant information to ensure data accuracy. 
  3. Optical Character Recognition (OCR) software converts the letters and numbers on the license plate into machine-readable text. This way, the system can identify the plate number.
  4. The recognized license plate number is compared to a database of known plates. Depending on the application, this database can contain information about vehicles associated with parking permit holders or other relevant data, like databases of stolen vehicles, outstanding warrants, or cars linked to Amber Alerts.

How Do License Plate Readers Work for Parking Enforcement?

LPRs automate the process of tracking and identifying vehicles in parking areas. This real-time data collection enables parking authorities to monitor parking durations and enforce time limits effectively. It also helps ensure that those who exceed their allotted time face timely enforcement actions, discouraging parking violations and creating a more equitable parking experience for everyone.

Using LPRs contributes to improved data analysis for parking authorities. With a wealth of license plate information, agencies can gain insights into parking patterns, seasonal changes, and occupancy rates. 

This data-driven approach helps make informed decisions about parking management strategies, such as adjusting pricing, optimizing parking layouts, and allocating resources more efficiently. 

Additionally, automatic license plate reader technology aids in long-term planning, enabling municipalities and their partners to address the evolving parking needs of every community.

How Do License Plate Readers Work for Issuing Citations?

Once a parking violation is detected, the automated license plate reader can automatically generate a citation and send it to the registered owner. This automation minimizes human error, ensures consistency in citation issuance, and optimizes the use of personnel resources. 

Furthermore, the system can deliver the citations electronically or by mail, simplifying communication and penalty notification. 

By freeing up officers from the tedious task of manual ticket writing, LPR technology allows them to focus on higher-priority aspects of parking enforcement, such as addressing customer inquiries and monitoring compliance.

A Word on Data Storage and Privacy

As a standard practice, License Plate Recognition systems store a comprehensive dataset comprising captured images, recognized license plate data, and associated metadata, like the capture's date, time, and location. This information is crucial for municipalities and third-party parking enforcement organizations, enabling meticulous record-keeping, transparent parking enforcement processes, in-depth analysis, and investigative endeavors.

Given the sensitivity of such data, various jurisdictions have instituted regulations and policies aimed at addressing concerns related to privacy and data usage. These measures often involve delineating specific data retention periods and imposing restrictions on LPR data usage. By doing so, authorities aim to balance technology for enhanced enforcement and individual privacy rights.

Moreover, these regulations also address concerns surrounding mass surveillance and the potential tracking of vehicle movements.

The Pros and Cons of License Plate Recognition Technology (Recap)


  • LPR technology minimizes manual efforts in parking enforcement, law enforcement, and other applications.
  • LPR systems enable real-time monitoring of vehicle movements for a quick response to potential security threats or criminal activities.
  • The technology provides high accuracy in license plate recognition, minimizing errors and false identifications.
  • LPR technology can contribute to overall crime prevention.
  • LPR systems generate valuable data on traffic management, urban planning, and trend analysis.


  • The widespread use of LPR technology raises privacy concerns, as it involves continuously monitoring and recording vehicle movements.
  • The storage and management of large amounts of license plate data pose potential security risks. 
  • The initial cost of implementing LPR systems, including installing cameras and software, can be significant.
  • The regulatory landscape for LPR technology is evolving, and compliance with privacy laws and regulations can be complex.

License Plate Readers FAQs

How Do License Plate Readers Work for Issuing Citations?

LPRs are generally legal for monitoring and enforcing parking regulations, but the specific rules and policies differ by location. Unauthorized access and misuse of LPR data can result in legal and ethical issues, so individuals and organizations using LPR technology must observe local laws and adhere to data protection best practices to ensure legal compliance.

Which states have license plate readers?

Numerous jurisdictions are still formulating or contemplating legislative measures that will expressly grant, define limits for, or impose restrictions on automatic license plate recognition. Currently, 16 states have proactively enacted legislation that delves into the nuanced deployment and operation of ALPR systems.

Can License Plate Readers be used for purposes other than parking enforcement?

Yes. Law enforcement uses them to locate vehicles associated with criminal activity, manage traffic flow, and enhance overall urban security.

Can LPRs track a vehicle's movement in real time?

Yes, law enforcement can use a police license plate reader for real-time vehicle tracking and retrospective location tracking. The versatility of LPR technology makes it a valuable tool in various domains concerned with public safety and urban management.

AI License Plate Recognition from gtechna

gtechna ALPR technology enables off-street and on-street parking enforcement for communities looking to provide citizens with an efficient and safe parking experience.

License Plate Readers (LPRs) by gtechna make cities smarter and safer — they simplify parking, enhance security, streamline traffic, and ensure everyone follows the rules. 

Do you have questions about how gtechna's ALPR technology can enhance efficiency and safety in your community? We're here to help! Reach out to us today for personalized insights and parking enforcement solutions.

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