What Is Up With Those Black Tubes Across Roads in Texas?

If you've ever been driving down a busy highway and suddenly you see black tubes across the roadway, then you've seen what are called "road tubes." Their official name is pneumatic road tubes.

These tubes are flexible rubber tubes stretched across a roadway. They work by compressing air as vehicles pass over them. Pressure change reveals much information as it is sent to data collection devices.

They can count the number of vehicles traveling over them, the number of axles, and even the speed and traffic intervals. These tubes are not routinely used to "spy" on individual drivers. Traffic engineers use the data to determine a wide range of traffic data.

The information is used by The Texas Department of Transportation or TxDOT engineers and planners to make decisions about roadway design, safety improvements, and other transportation projects. The tubes can also be used to measure bike traffic or pedestrian traffic.

When you see more significant numbers in a given area, it usually means the area is slated for evaluation for possible improvements and upgrades.

Road tubes were invented in the 1930s, and initially, they were made of metal. That must have been a little unsettling to drive over. In the 1960's the tubes began to be constructed of the rubber materials used today.

It is not widely known, but road tubes are often used to determine seismic activity. The tubes can detect earthquake activity by detecting the vibrations caused by seismic waves. With the recent upswing in earthquake activity here in West Texas recently, it might be a good idea to deploy more of them.

They could detect earth movements and cross reference with fracking activities to see if a particular fracking operation is causing increasing activity that could lead to a damaging earthquake.

I've always wondered what happens if you stop on a road tube.

It turns out that stopping on a road tube affects the accuracy of the collected traffic data. That is one of the reasons why more than one tube is installed in each location, so the other tube can continue to collect accurate information in the event of that happening.

If you are curious about road tubes, we have included a video describing them in detail.