I’m always wondering what the purpose of those odd black tubes in the road is used for. Fortunately, I finally found the answers to those weird black tubes. And no, it’s not a goofy elaborate watering system.

The official name for these ominous road snakes is just “pneumatic road tube,” and if you guessed that they probably just take a traffic count, you are mostly correct. But they also do so much more!

They are used for short-term traffic counting, vehicle classification by axle count and spacing, planning, and research studies.

Some models gather data to calculate vehicle gaps, intersection stop delay, stop sign delay, saturation flow rate, spot speed as a function of vehicle class, and travel time when the counter is utilized in conjunction with a vehicle transmission sensor.

Pneumatic road tubes can be set up to be either permanent or temporary, and temporary configurations are usually only installed for about a day. Permanent installations are linked up to a counter device that’s kept in a permanent roadside lockbox.

For the more-common temporary setup, the tubes are stretched across the road perpendicular to traffic until there’s very little slack. On one end, they’re held in place in the road using a concrete nail, and the tube is pinched shut. On the other end, the tube is fed into a counter device that is chained to a street sign or post to make sure it doesn’t go anywhere.

According to the Federal Highway Administration:

“Advantages of road tube sensors are a quick installation for (the) permanent and temporary recording of data and low power usage. Road tube sensors are usually low cost and simple to maintain. Sensor manufacturers often supply software packages to assist with data analysis.”

If you’re looking to game the system, you can drive over the tubes on the roads you want to be repaired. While it isn’t a guarantee, it only makes sense that your local officials will pay more attention and give more funding to busier roads.

You can see how it works in this video from the City of Bloomington, Minnesota’s YouTube page:

Watch the video explanation of Road Tubes here: CityOfBloomingtonMN/Youtube

Source: AWM

 

 

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