I know this has happened to you. You are driving down the road and all of a sudden you see this black long tube all the way across it. You drive over it with no problem but then you wonder, what the heck is that black tube used for and why on this road?  Those long black tubes are called a pneumatic road tube and they are used for a few different reasons. According to the U.S. Office of Highway Policy Information, they calculate how many vehicles use that specific road per day. It also helps to figure out patterns of traffic and how many different types of vehicles travel on that road.

The technology is pretty cool too. When the car passes over the tube, it releases a burst of air. That air pressure sets off an electric signal and that information is delivered to software.

The data collected can tell the city how fast people are driving in that area and then post more visible speed limit signs. It can calculate how busy the roadway is to help in determining stop sign and traffic light locations. It can also help with adjusting traffic patterns. Plus police can get a better idea if people are speeding on that road.

Now when you drive over those black tubes, you won't have to wonder. You're welcome!