MUNDANE MYSTERIES: What Are Those Black Tubes Randomly Across The Road?

Anyone who’s ever been behind the wheel of a vehicle driving down a given thoroughfare has most likely noticed the skinny black tubes that seem to appear across the asphalt seemingly at random.  What are those little black tubes? And why are they there?

Those little black baby speed-bumps (actually rubber cords) are officially known as “pneumatic road tubes”, and they’re used by various municipalities & governments. They’re actually a pretty simple technology, too: every time a vehicle’s tires roll over the tube, a burst of air triggers a switch that sends an electrical signal which gets recorded by a counting mechanism. There are some roads that do have permanent pneumatic road tubes, but most are only temporary & are usually in place for only a few days at most.

The setup is simple, but the data it records gives government agencies a whole lot of info about traffic patterns in that area. A single pneumatic tube can track the number of cars driving over a road in any particular span of time. By measuring the time that passes between air bursts, agencies can determine the time of day with the highest amount of traffic & congestion. A double pneumatic tube setup, where they’re installed slightly apart from each other, is able to paint an even broader picture for officials by gauging the class, speed, and direction of each vehicle that passes over them. Then, based on the data collected, the town, county, state, or federal government (whichever level is conducting the research) can determine which speed limit & road signs are or aren’t working before deciding where & how to allot the appropriate amounts of money in their transportation budgets.

So, keep an eye out for those pneumatic road tubes while you’re out & about.  And if you’ve got a Mundane Mystery you’d like solved, send me an email:

BROUGHT TO YOU BY: Berryville Graphics