Here’s Why Some Colorado License Plates Have Spirals On Them

Have you ever noticed that some Colorado license plates have two ribbon-like lines, located right in the middle under the dash? This helix is more than just a random design feature.

These light-gray wavy lines help Colorado law enforcement visually identify counterfeit license plates.

The technical name for the markings is "Ensure Virtual Security Thread" and the anti-counterfeiting product is made by 3M. The threads use retroreflective sheeting, which is a technology that consists of glass beads or microscopic prisms to return the light. Road signs have been coated with this sheeting for almost 100 years and license plates since the 1940s. It’s the reason that signage and other plates appear to light up when your headlights hit them.

In addition to the spirals, other Colorado license plates may have a different reflective watermark, like a light faint "C" but they still serve the same purpose. If you shine a flashlight on your license plate, the squiggly lines (or whatever the other design is) are easier to see. These holograms help police officers validate a legitimate license plate during a traffic stop.

Twenty-six states, including Colorado, use security threads on license plates.

Oppositely, six states, Connecticut, Kentucky, Maryland, Pennsylvania, Ohio, and New Hampshire have no counterfeiting stamps, seals, or threads on their plates.

Colorado License Plate by Broz1014/ CC BY-SA 4.0