You’ve probably noticed those black rubber tubes stretched across streets and wondered what they are. These modest cylinders, called traffic counters, are far more important than they look. Used by transportation professionals and community organizations, they quietly record critical data about traffic flow and roadway usage. Across the U.S., more than 12,000 are in place, shaping the way cities plan and manage streets.
The concept behind them is surprisingly simple. When a car’s tire rolls over the tube, it compresses air inside, sending a pulse to a counter device. A single tube records vehicle counts and traffic flow, while two parallel tubes capture more detailed data—speed, vehicle type, and even travel direction.
This information isn’t just academic. It influences speed limits, traffic signs, safety strategies, and funding for road projects. Temporary counters may stay in place for a day, while permanent ones provide continuous monitoring. Transportation departments rely on this data to investigate complaints about speeding or shortcuts and to refine city planning.
Next time you see those black cables, remember—they’re silent observers, measuring the pulse of our streets and guiding safer, smarter transportation decisions.
