You've probably not put much thought into it (I haven't), but seeing the yellow lines running down the middle and the white lines on both edges of Indiana roads at night is pretty important. They keep us from drifting into oncoming traffic or running off the road. While I've always thought the natural color of the paint causes those lines to reflect in our headlights, it turns out there's a little something added to it that causes those lines to pop off the pavement.

All About Reflection

Look, I realize that how the Indiana Department of Transportation gets the lines to be reflective isn't the sexiest bit of information in the world, but I'm the kind of person who is fascinated by the way things work. So, when I recently saw the Department's post on Facebook sharing how they do it, I found it to be pretty interesting, and I thought you might too.

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The secret is glass. Not busted shards, obviously. I don't think the Department of Transportation has it in the budget to replace tires that have been shredded just from driving down the highway. What the Department uses is tiny beads of glass that are created specifically for the purpose of being applied to the lines in the road.

But they don't just throw random glass beads in with the paint. There is some science to it.

...these beads are tested in a laboratory for percentage of roundness. This is crucial because the shape of the glass beads is important for their reflectivity. They are also shaken through a specific set of different sized sieves to determine the amount of each size of bead. This combination of sizes creates a jigsaw puzzle-like surface when they are applied. Finally, the beads are checked for water resistance. Without this feature, the beads would clump together when exposed to moisture and clog the nozzle.

Once they have the bead situation set the way they want, they spray them on top of the wet lines of paint. As the paint dries, it essentially "cements" the beads to the road.

I couldn't find a video from INDOT showing how the process works, but this video from Maine explains it well.

Pretty cool, right? Feel free to use this newfound knowledge to wow your friends.

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Gallery Credit: Sarah Jones