These hockey pucks are part of a system that keeps traffic moving.

Ever drive across or walked by what looks like a black, circular hockey puck stuck in the road?

They’re often near intersections, a couple yards away from a traffic light.

If you guessed they’re some sort of sensor, you’re 100 percent right

Steve AKA the @TrafficLightDoctor on TikTok recently posted up a video explaining just exactly what these pucks are.

Check out his video below.

@trafficlightdoctor How vehicle detection works and how it picks up motorcycles!! #trafficlightdoctor #fyp #tiktokshop #sponsored #educational ♬ original sound – ???? Traffic Light Doctor ????

“You may see some cut-outs in the road similar to this,” Steve begins to explain.

“This is actually a sensor in the road that connects wirelessly to this intersection, and as vehicles travel over it…it puts in a call for it to get the green light.”

Steve then pulls out an actual sensor, presumably to replace the battery.

“This one got covered up with the sealant. All this is a housing with a sensor and a battery, and it’s placed in the holes in the asphalt, and sealed on top and this will detect your vehicle as you drive over the top of it.”

Steve then shows the control cabinet housing all the equipment that facilitates communication between the sensors and the traffic lights, the brains of the operation.

“Those wireless pucks talk back into the controller and through this card rack…it’ll lock in a call when there’s a vehicle present on top of the wireless puck that will put in a call for someone to get in a green light.”

Doing my own research, these pucks may also be called Wireless Magnetometers for vehicle detection.

You can even buy them on Alibaba. If you put in a bulk order, you can get them for as cheap as $10 a puck.

According to Steve in the comments, the batteries are supposed to last between 4-6 years, with the manufacturer I linked above claiming up to 10 years.

In reality, most of the batteries only last up to a year.

So, now you know exactly what those black pucks are.

If you want a green light, you’ll have to drive over it.


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