Other States laws/regulations; Program Description;

OLR Research Report

November 6, 2012




By: Duke Chen, Legislative Analyst II

You asked for information on automatic license plate recognition (ALPR) systems, specifically if (1) Connecticut has had any proposals banning their use, (2) any states ban or limit them, and (3) any countries have banned them.


Generally, ALPR systems automatically capture an image of a vehicle's license plate and compare the plate with one or more databases of vehicles. ALPR systems can be deployed in police cars or mounted at an intersection and be used to find stolen or uninsured vehicles. But there are concerns about inaccurate data and privacy when it comes to ALPR use.

We were unable to find any proposed legislation in Connecticut that would ban ALPR systems, but there has been at least one proposal limiting the data retention period.

At least two states, New Hampshire and Maine, have laws limiting ALPR technology. New Hampshire has, with certain exceptions, a general ban. Maine only allows certain public safety agencies to use the technology. These agencies can retain the information for up to 21 days. In addition to these state laws, New Jersey, through an Attorney General Directive, provides a guideline for its law enforcement agencies, which includes limiting their data retention to five years.

We were unable to find any countries that completely ban ALPR systems.


Law enforcement agencies throughout the nation are increasingly using ALPR technologies to enhance their enforcement and investigative capabilities. They use the technology to expand their collection of relevant data and expedite the time consuming process of license plate comparisons.

The database expansion combined with the rapid results of the scans allows law enforcement to find uninsured or stolen cars more quickly and efficiently.

How ALPR Works

ALPR systems (1) automatically capture an image of a vehicle's license plate, (2) convert the image into alphanumeric characters, and (3) compare the number with the database of interest. All of this occurs in seconds, which allows law enforcement to quickly determine if the car is stolen, uninsured, or wanted for other law enforcement reasons.

Concerns About the Technology

There are concerns about inaccurate data and privacy with the use of ALPR technology. If inaccurate data is added to the databases, there could be false hits due to the faulty data.

There are also privacy concerns about law enforcement agencies recording the location of a person's car. In addition to the privacy concerns arising from the scans themselves, there are concerns about how long the data is retained.


We were unable to find any proposed legislation that would have banned ALPR systems. But, there has been at least one proposal to limit the data retention of ALPR technology.

In 2012, the public safety committee held a public hearing on HB 5391. The bill would have required law enforcement agencies that use ALPR systems to expunge the data from the system within 14 days after collection, unless the data was relevant and material to an ongoing criminal investigation or prosecution.

After the public hearing, the Public Safety Committee referred the bill to the Insurance Committee. The Insurance Committee approved a substitute bill by a 15-4 vote and referred it to the House floor, where no further action was taken.


New Hampshire

New Hampshire generally bans surveillance on highways, including the use of ALPR systems (N.H. Rev. Stat. Ann. 236:130). This prohibition includes the state as well as private citizens.

The New Hampshire law does allow for certain exceptions, including certain investigatory, traffic, and security purposes.

Any person violating these provisions is guilty of a violation, which is punishable by up to a $1,000 fine. Other entities violating these provisions are guilty of a misdemeanor, which is punishable by up to a $1,200 fine.


Maine only allows its departments of Transportation and Public Safety and law enforcement agencies to use ALPR systems for certain public safety purposes (Me. Rev. Stat. Ann. 29-A, 2117-A).

The law provides that the data that is collected is confidential and can only to be used by law enforcement in carrying out its duties. Furthermore, the data collected or retained may not be stored for more than 21 days.

A violator is guilty of a class E crime, which is punishable by up to six months imprisonment and a $1,000 fine.

New Jersey

Through a New Jersey Attorney General Directive, law enforcement in the state must adhere to certain guidelines (http://www.state.nj.us/oag/dcj/agguide/directives/Dir-2010-5-LicensePlateReadersl-120310.pdf).

These guidelines include limitations on when ALPR systems may be deployed, used, and who is qualified for such use. In addition, each department that uses an ALPR system must keep a record of when and where it was deployed, if it was mobile or fixed, and if any data was transferred or stored.

The guidelines also require all records of ALPR activity to be maintained for five years and be readily accessible for audit. After the five years, the data must be purged from the system.