What Are the Black Cables on Indiana Roads?

Ever Wonder What Those Black Hoses on Indiana Roads Are For?

If you’ve driven on Indiana roads, you’ve probably crossed over those two black hoses stretched across the pavement. As your tires roll over them, you hear that unmistakable "thump, thump." But have you ever stopped to wonder what they’re doing there? Were they left behind by a construction crew? Are they part of some sort of cable theft operation? Or maybe they're being used for a speed trap? The answer to all those questions is no! These hoses are actually there for a very good reason.

What Are They?

Let’s clear up what these hoses really are. They’re not cables; they’re rubber tubes known as "Traffic Counters," placed by the Indiana Department of Transportation (INDOT) to gather traffic data.

Indiana isn’t alone in using these; nearly every state across the country employs similar systems. While I couldn’t find a video from INDOT on how they’re installed, check out this behind-the-scenes look from the Michigan Department of Transportation:

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How Do They Work?

The technology behind these hoses is pretty straightforward. According to Mental Floss:

"Every time a vehicle’s tires hit the tube, it sends a burst of air that triggers a switch, which then produces an electrical signal that’s recorded by a counter device."

These signals help INDOT track "volume, speed, and vehicle classification data." Some counters even use "weigh-in-motion (WIM) technology" to collect weight data from trucks.

Why Collect This Data?

In a 2020 interview with WTWO-TV in Terre Haute, INDOT Deputy Commissioner Debbie Calder explained that the department uses the data for a variety of purposes.

So the next time you see those hoses on the road, you’ll know you’re helping the state gather important traffic information. Feel free to drive over them confidently—just remember to stick to the posted speed limit!

[Sources: MichiganDOT on YouTube / Mental Floss / WTWO-TV on YouTube]