Here at the Curiosity Desk, we love nothing more than when we hear from our listeners about the things — large and small —that are rousing their curiosity. Inspiration for today's story comes courtesy of Worcester resident Richard Klein.
On Massachusetts license plates, there’s a pattern going vertically down the center of the plate — looks kind of like a double helix, and I’m just curious why it’s there.
It turns out, this ghostly, gray double helix has an official name: the “Ensure Virtual Security Thread.” It was created by 3M, a company in the midwest that you might know as the makers of Scotch Tape and Post-It Notes, but who think of themselves a bit more broadly.
"We’re actually a 115-year old global science company," said Christopher Ede, Global Business Manager for 3M's Vehicle Materials division. "We think of ourselves as innovation at our core."
Early in the 20th century, the folks at 3M invented a breakthrough product that has stood the test of time: Retroreflective sheeting.
"Retroreflectivity is actually accomplished using glass beads or microscopic prisms to return the light," explained Ede. "Light would actually come into the sheeting and bounce around the beads or the prisms and then get sent back out."
Road signs began to be coated in the sheeting in the late 1930s, and license plates in the 1940s. It’s why both objects appear to light up when your headlights hit them.
The sheeting is also on all kinds of other things. It makes barcodes readable from greater distances and enables holograms on driver’s licenses. It's also also what allowed the effects team at Industrial Light and Magic to create the iconic lightsabers in the original "Star Wars" back in 1977.
In the 1980s, 3M began embedding a new technology inside their retroreflective sheeting for license plates — a security feature aimed at curbing counterfeiters.
"When a police officer pulls over a vehicle it’s something they will look for," explained Ede. "And they can detect counterfeit plates before they approach the vehicle."
Ede says the double helix shape of the Ensure Virtual Security Thread was chosen for its unique properties, devised and designed by experts in their film, imaging and light management divisions.
"It essentially creates this floating image, is what we call it," he said. "It's very easy for authorities to see, but it’s very difficult to simulate and counterfeit."
So does it work? I put it to the test, shining a flashlight in the dark on my license plate. The whole plate lit up. And while I’m not so sure I’d call it a floating image, the security thread was nevertheless highly visible, especially from about eight feet away. And as I approached the plate, something interesting happened about three feet out. The security thread disappeared, and three circles, with letters and numbers inside them, emerged.
This particular trick of light is unique to Massachusetts plates. Ede says many states also add their own custom security features like this to the standard-issue Ensure Virtual Security Thread.
In addition to that DNA strand, there is other information embedded in the Massachusetts license plate. And with the Sumner Tunnel closure, and the Green Line Extension shutting down, chances are you’ll be spending more time than you’d like in traffic this summer, so why not use this opportunity to get acquainted with the back of the car in front of you?
For a primer on what else you can glean from the Massachusetts license plate, check out the latest video from The Curiosity Desk.
