What Are These Black Cables Doing on Minnesota Roads?

If you spend any amount of time traveling Minnesota's highways and roads, you've probably noticed them: The skinny, black tubes, carefully stretched across streets. But what are they used for anyway? As it turns out, there can be a few different answers to that question.

The Minnesota Department of Transportation, along with local towns and counties place these black tubes all over the Land of Ten Thousand Lakes for a few, very specific reasons.

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What Are These Black Tubes Doing on Minnesota Roads?

Officially known as "Pneumatic Road Tubes", these snake-like cables are strewn across Minnesota roadways for a number of reasons.

Pneumatic road tube sensors send a burst of air pressure along a rubber tube when a vehicle’s tires pass over the tube. The pressure pulse closes an air switch, producing an electrical signal that is transmitted to a counter or analysis software. The pneumatic road tube sensor is portable, using lead-acid, gel, or other rechargeable batteries as a power source.

-U.S. Department of Transportation

These cables can be used for:

• Counting Cars
• Measuring Traffic Flow
• Measuring Speed
• Planning
• Research Studies

Cables like this have been around for many years and the data collected from them allows local cities and towns, along with the Minnesota Department of Transportation to learn more about the roads and traffic flow in any given area.

To learn more about these Minnesota road cables, how they're set up, and the data they collect, check out the YouTube video below.

Story Sources: MNDOT, Jalopnik