Have you never noticed black cables running across the road while you were driving around town? These are actually an important tool in road planning.
When you’re driving along a suburban or small town road, there are certain differences you might notice from other kinds of roads, like highways. In particular, when driving through a high-traffic area like an intersection, you might spot one or two thin, black cables running from one sidewalk to the other, crossing over the road you’re about to drive over. These cables are generally small enough that you barely feel your car moving over them, and if you didn’t see them, you might not even know they were there.
These black cables are pneumatic road tubes, and they’re a vital instrument for local governments to measure the state of traffic in their towns and cities. Unlike something like cameras installed on traffic lights, pneumatic road tubes utilize much simpler air-based technology to measure the number of cars coming and going in a given period, as well as the speed at which they’re driving. This information can be used to identify problems like road congestion and get important development projects like road redesigns in motion.Pneumatic road tubes are activated by the pressure of a passing car
A pneumatic road tube uses a very simple form of measurement and registration, one that has also been used to control traffic lights that detect cars: good old-fashioned airflow.
