Those roadside sides warning you about your speed may be watching you. And multiplying, too.

In a development sure to spike one’s Digital Age paranoia, Quartz is reporting that the Drug Enforcement Administration is expanding its national network of license-plate readers (LPRs) and hiding them inside roadside signs that warn motorists they’re traveling above the speed limit.

The website, citing recently released data from federal contractors and DEA budget documents, says the agency intends to broaden data collection on motorists that can be shared with law-enforcement authorities at all levels of government. The aim is to build a cooperative data-sharing system that can be used to target drug trafficking, money laundering and other criminal activities by monitoring busy roadways, particularly along the Mexican border. Northeast and southeast corridors are also a primary focus of the effort, the website says. The DEA’s program has been around since 2008.

“There are license-plate readers all over the place,” DEA special agent Melvin Patterson, a spokesman for the agency, said in an interview Monday. “It’s just now becoming more popular to have those in cities.” He said the devices are very useful investigative tools not only for intercepting drug dealers but also for thwarting potential terrorist attacks or gathering evidence after one occurs.

But civil rights groups such as the American Civil Liberties Union say the breadth and lack of transparency of such networks are more than a little chilling.

“The government is basically seeking to collect information on everybody just in case it needs it. That gives the government the power to press rewind on anybody’s life, and see where they’ve been,” said Jay Stanley, senior policy analyst at the ACLU. “And that’s more power than government should have for a free people.”

Plate readers — which resemble closed-circuit TV cameras and are frequently seen mounted on the rear of law enforcement vehicles or roadside poles — can photograph thousands of plate numbers in minutes from passing vehicles. Software then analyzes the data for matches to police alerts. Their deployment has become more common since Britain used them to deter Irish Republican Army attacks in the 1990s. Many agencies in the United States began using them after the terrorist attacks of Sept. 11, 2001, and they are ubiquitous on the U.S. border in the Southwest.

The ACLU has no objection to the limited use of such devices, such as searching for stolen cars, Stanley said. But the group expressed concern, warning that abuses could flow from the mass amounts of data that the devices collect and store. Stanley said the ACLU worries as much about the potentially disquieting effect on people as it does about possible abuses.

“It can reveal not only where you go but who you’re with,” Stanley said. “That’s an enormously powerful set of information. It creates a risk of abuse, and it risks creating chilling effects. It’s creating the world where Americans constantly feel, even when they have nothing to hide, that the government is watching them.”

Patterson, the DEA spokesman, acknowledged that any investigative tool has the potential to be misused. But he also said the law enforcement agency treats such data carefully with multiple levels of oversight to prevent abuses.

"I don’t have a problem with it, me as a private citizen, because I’m not trafficking drugs. So I have nothing to worry about, and neither does anybody out there who’s not violating the law,” Patterson said. “It’s used as a tool, and we have a responsibility to the American people to keep them as safe as possible and keep drugs from coming into their community.”

In a July 2013 report titled “You Are Being Tracked,” the ACLU warned that government agencies could use the data to track people who lawfully attend public demonstrations. The group also raised concerns about the security of the database, suggesting lapses might allow unauthorized people to track other people’s whereabouts.

“If not properly secured, license-plate reader databases open the door to abusive tracking, enabling anyone with access to pry into the lives of his boss, his ex-wife, or his romantic, political, or workplace rivals,” the ACLU report says.

If anything, however, the devices have continued to multiply since the report appeared, as reflected in Monday’s report by Quartz. The ACLU urged the government to be more transparent about the deployment of plate readers so that Americans also have some say about how the devices are used.

“We don’t live in a world where peaceful political protesters feel like they have to worry. People shouldn’t have to go through life having to live under the third eye,” Stanley said.

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