Automatic License Plate Reader or ALPR are computer-controlled cameras that are designed to read and record the license plates of cars as they drive past. Can you stop ALPRs from reading your plate? Yes, but most options that do aren’t legal and can cause you more trouble.
Plastic wrap, license plate frames, and license plate covers are rumored to stop the ALPR from capturing the license plate of your vehicle. Most of these products will not stop the ALPR and the ones that do aren’t legal to use on your vehicle.
Let’s look at some of the products that are marketed at stopping the ALPR and how they fail.
How ALPR’s Work
The ALPR contains a camera, a lens, and either an internal or external computer that contains the software to read the license plate.
When a license plate passes in front of the ALPR it will convert that image to text using the character reading software. It also records the time and location of the license plate that was read. It can check that license plate against a database.
How Accurate are ALPRs?
ALPR can read over 99% of the license plates that pass in front of their cameras. The ALPR was able to spot license plates through a difficult variety of tests.
It was able to pick up license plates in different locations such as in the windows of vehicles. It is also able to capture temporary license plates made out of paper.
License plate frames, stacked characters, and even handwritten license plates were all able to be read and captured by the ALPR cameras.
It is able to read license plates with emojis and even license plates on cars that had a bunch of signs and stickers on the cars, even if some of the stickers and signage were close in font and color to the actual license plate.
How Many Pixels Do You Need to Read a License Plate?
The ALPR camera did fail to read a license plate with 28 pixels plate width. The license plate with 30 pixels plate width as well as higher pixel plate width were all able to be captured by the ALPR camera system.
Is ALPR Able to Read License Plates in Low Light?
When tested, the ALPR was able to read license plates in all light conditions. They do not rely on the flash from a camera to illuminate the license plate.
Lightness level -93 were no match for the ALPR to read and record the data of the license plate.
The ALPR cameras are remarkably accurate when reading license plates on vehicles. They were able to capture license plates in low light, blurry, and low pixel quality.
Products to Block Your License Plate
There have been many products that are marketed for stopping the ALPR from getting a clear view of your license plate.
They try to reflect the light from the reader and obscure your license plate. Here are some of the latest myths that don’t work.
- Plastic Wrap
Wrapping your license plate in plastic wrap is said to be able to thwart the camera from reading your license plate. The truth is that even if it can blur your license plate, it will not make it unreadable.
- Aluminum Foil
The myth of wrapping aluminum foil around the edges of the plate does not affect the ability of the ALPR to read your plate.
- Covering up or Scratching Out
It is unclear if the ALPR will be able to read the license plate if you deliberately cover the plate with snow or mud. It will attract the attention of any police that happen to see it. I would rather have the camera see it.
Do License Plate Covers Work?
When evaluating if an ALPR will be able to read your plate, if you can read it, they can too. Anything you put over the license plate reader will not be able to block the reader unless it blocks your vision also.
According to Road and Track, putting anything over your license plate to obscure it or hide it will be illegal in all 50 states.
The ALPR’s cameras and computers were able to pick up plates in blurry conditions and dark conditions. They do not use a traditional camera flash, which could reflect off of the cover used to block the license plate.
Any cover that would be able to prevent the ALPR from reading your plate would block anyone from viewing it also.
Flip Down or Retractable License Plate Covers
The only way to keep the ALPR from reading your license plate is to just hide it with a license plate flipper. I doubt the ALPR will be able to see it if it’s hidden. I also doubt that would be considered legal in any state.
They are novelty items. You would be inviting serious legal trouble if you did use it on a public roadway to block your license plate for any reason.
The only legal way to keep the ALPR from reading your plate is to not pass in front of it. If you can read your plate, the ALPR can read it also.
To check the current price and availability of license plate flippers, click here to view the listing on Amazon.
Final Thought
The accuracy of these cameras is hard to fool. They do not use a flash to view the license plate so covering the plate is not effective. They are not tricked by license frame covers or vehicles with bumper stickers or signs. Despite the high accuracy of these cameras, products and myths are still floating around claiming that they can obscure the license plate of your car.
These claims are highly inaccurate and their products may be illegal for use on your vehicle on a public roadway. Every one of the 50 states has some law that makes it illegal to cover your plate or intentionally cause it to be illegible.
If you are unable to read the plate because it’s covered, it’s not legal and will attract the attention of law enforcement you happen to encounter. That would be the opposite of what you are hoping to accomplish.