Have you ever noticed tiny flashes of light illuminating your way home while driving on Indiana highways? The Indiana Department of Transportation has unveiled a little-known technology it says could help drivers in the state.
These glass beads are called “safety beads.” These colorless, nearly transparent spheres reflect the light from a car’s headlights back to the driver. According to the Indiana Department of Transportation, safety beads are designed to improve traffic direction and road markings by making them clearer, thereby increasing safety.
”The light from your headlights hits them and reflects back into your car, so even in pitch black darkness you can see them,” said Hunter Petrowiak, spokesman for the Indiana Department of Transportation’s Northeast District. “If you hold it in your hand, it feels like sand. If you squeeze it, it’s very soft. You can barely see it on the paint.”
However, a recent post on the Indiana Department of Transportation (INDOT) Facebook page intended to clarify what glass beads are has unintentionally angered some Indiana drivers, with many users writing that glass beads should not be used to replace reflectors on Indiana roads.
”Something needs to be done!!! Whether it’s glass beads, glow in the dark stripes, I don’t know… even just repainting them when they’re no longer visible,” one Facebook user commented.
However, the Indiana Department of Transportation (INDOT) reminds that glass beads are only used when painting roads in Indiana. They are not a replacement for reflectors, but are part of the painting process.
While the road marking sprayer sprays paint onto the road through one nozzle, the second nozzle sprays glass beads directly onto the wet paint.
”Wet paint creates a texture similar to cement. In fact, we only create these lines when we apply glass beads,” Petroviak said.
According to the Indiana Department of Transportation, which designed the spheres to give the painted lines a reflective effect, the balls will stick to the markings once the paint dries.
”They go through rigorous testing to ensure that at least 80 percent of the balls in a batch are spherical,” Petroviak says.
The glass spheres are weather-resistant and undergo rigorous testing at the U.S. Department of Transportation’s Materials and Testing Buildings and testing facilities throughout Indiana, including Indianapolis, before they are installed on roads.
Scientists tested the spheres for reflectivity and percentage of roundness to help them stay on the drawn line as intended.
The balls are also sifted through a special set of sieves of different sizes to determine the number of balls of each size.
Different sized granules are combined to form a puzzle when applied to a painted surface. They are then tested for water resistance. The Indiana Department of Transportation (INDOT) says that without water resistance, the granules will stick together when exposed to moisture and clog nozzles.
”I think it will be interesting to people because when you hear that we’re going to put glass on the ground, it’s a little weird,” Mr. Petroviak said. “It sounds like the paint is going to reflect the light.”
Each Indiana Department of Transportation district and several contract partners across the state are responsible for their own painting projects.
Post time: Aug-14-2025