License plate scanners pose serious privacy threats

Anton P. | July 26, 2022

License plate scanners are surveillance systems combating crimes like vehicle theft, burglary, and speeding. In the past, this technology was most relevant to law enforcement agencies. However, this technology has become available to the general public, with options to install it on house cameras. 

License plate scanners can be helpful in criminal investigations, like locating stolen cars. But they become unpredictable when their silent purpose is to track the movements of innocent people as well. So, let’s see the privacy and security problems that arise from having license plate readers installed anywhere. 

License plate scanners pose serious privacy threats

What are license plate scanners? 

Automated license plate scanners or readers (ALPRs) are camera systems capturing the license plates of cars that pass them. Law enforcement agencies use license plate readers to track the movements of suspects or catch speeders. 

However, it can be after any type of criminal activity. Fort Worth police have equipped cameras and license plate scanners to catch culprits lighting fireworks in the city. 

Usually, specialists place ALPRs on street lights, poles, mobile trailers, or patrol cars. So, they scan all cars within reach, collecting their license plates, date, time, and location. Therefore, they perform vigilant location tracking, making it possible to map out drivers’ movements. 

The official purpose of license plate scanners is to contribute valuable information to criminal investigations. They can supply details on where vehicles were at the time of a crime or discover driving patterns. 

However, these scanners track much more than individuals associated with specific investigations. It can track the movements of ordinary people, likely without their knowledge or consent.

A disturbing notion is that such scanners could determine the people visiting sensitive places, like abortion clinics or protests. So, license plate scanners have many privacy implications. The situation worsens when such technology enters the hands of regular consumers. Also, cars can know much more about their drivers than ever before.

How do license plate scanners work, and what do they collect? 

Older license plate scanners lacked real-time online access and were somewhat limited. For instance, they could only be in places with the power to charge them. Modern gadgets are much easier to manage. They can be anywhere, with solar cells recharging their batteries. Additionally, their logs can quickly reach central cloud repositories. 

Such devices are trained cameras that detect alphanumeric codes on cars. When they capture a vehicle, the system can automatically log various information:

  • License number.
  • Location. 
  • Time. 
  • Vehicle model or its partial image. 

Photos taken by license plate scanners can also include or contribute to discovering other details: 

  • Passengers in the car. 
  • Direction and speed. 
  • Travel patterns. 
  • The driver’s identity.
  • Bumper stickers. 

An extensive network of scanners could log information about people’s driving patterns. Photos linked to a specific license plate can reveal drivers’ routines and commonly visited places. 

Since license plate scanners can log each passing car, it tracks millions of ordinary people. As a result, such technology can fuel a powerful surveillance system, invading the privacy of innocent people.

Anyone can purchase license plate scanners 

License plate scanners were expensive, meaning police departments and agencies were their primary users. However, companies like Flock and Motorola Solutions have introduced more affordable readers, meaning regular people become potential users. 

The transparency of surveillance and police tools has been questioned before. Consumers accessing such monitoring equipment can help build an even broader network for surveillance. However, some readers for homeowners might not log all cars but those specified. 

Privacy concerns about license plate scanners 

  • Retaining data longer than necessary. In the US, states follow different rules for preserving data from license plate scanners. In Montana, entities cannot keep this data for longer than 90 days. However, there are cases where such data gets preserved for up to one year
  • Sharing data with partners, agencies, or companies. It can be challenging to determine who gets access to data gathered via license plate scanners. Sometimes, searchable databases can be available to hundreds of other agencies. A study in 2018 revealed that such details could be accessible by 160 jurisdictions. In more severe cases, the numbers can be close to 900 agencies. Here are some parties that could access drivers’ data: airports, police departments, university police units, and more. 
  • Potential tracking of people visiting sensitive locations. It could be fairly easy to set license plate scanners in sensitive areas, like political rallies or immigration clinics. 
  • Difficult to evaluate the efficiency of license plate scanners. Law enforcement agencies claim that license plate readers are valuable additions to investigations. However, their contribution is difficult to determine. Specialists have estimated that over 90% of scans are of innocent people’s cars. So, this extensive surveillance mechanism seems to fail in proving its worth. 
  • The scanners can trigger false positives. Cameras could misread license numbers. In fact, statistics show that a third of detections of potential criminals can be faulty. 

Is safety worth sacrificing privacy? 

Law enforcement’s promise with license plate scanners bolsters security in cities, neighborhoods, or homes. However, this technology enables massive data collection and mirrors concerns seen with public facial recognition

In both cases, millions of ordinary people have their data logged without their knowledge. Furthermore, sharing information from license plate scanners across states or departments makes it difficult to control. 

The shared data might lack necessary oversight, such as access controls or protection against breaches. If license plate numbers and locations associated with them get compromised, it poses risks to people’s physical safety. 

For instance, it could reach robbers or stalkers, discovering when individuals leave their homes. More disturbingly, it can fuel hate crimes against people with certain political beliefs or if they belong to minority groups. 

Are license plate readers worth the privacy invasion?

The helpfulness of license plate scanners is not overwhelmingly positive. There are claims of its hit rate being 0.5%. Therefore, this technology generates millions of logs for capturing a relatively humble number of potential criminals. 

Lastly, license plate scanners have become available to everyday consumers. Some of them might agree to share the images they capture with law enforcement. Thus, this type of movement tracking casts an even wider net. It also means more people might be stripped of their privacy. They could also end up subjected to false arrests due to incorrect license plate scanner results. 

If this technology continues to grow, governments must consider establishing strict and clear-cut laws for its use. Data retention, protection, and limited sharing are key requirements in this case.

Anton P.

Anton P.

Former chef and the head of Atlas VPN blog team. He's an experienced cybersecurity expert with a background of technical content writing.


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