The Street Has a Network

The light is what you see. The computer is what runs it.

Next time you're stopped at a red, look at the corner. There's a gray metal cabinet, about the size of a refrigerator. Most people think it holds wires.

Open the door and you'll find a small data center.

The controller sits in the middle. It reads the sensors and decides when each light changes. Next to it is a network switch. A radio on the pole above links the cabinet to the next intersection, or back to the traffic center. A camera on the mast arm sends live video so engineers can watch the corner from their desks. Loops cut into the pavement, or video detectors, tell the controller a car is waiting. A receiver listens for fire trucks and ambulances so it can turn their light green.

And there's one more board, the quiet hero of the cabinet. It's a safety unit wired into the hardware. If the controller ever tries to give green to two directions that would collide, this board overrides it and drops the whole intersection into flashing red.

Count them up. Controller, switch, radio, camera, detectors, emergency receiver. That's six computers or more on one corner. Multiply by every signal in your city.

Now ask who owns them.

Traffic engineering owns the timing. IT may own the network, or may not even know it exists. Signal technicians own the hardware. A contractor installed half of it and still holds the passwords. The vendor has a remote login for support. Each one touches the cabinet. Nobody owns the risk of the whole cabinet.

That gap is where attackers like to work.

Ask your team: Could you list every connected controller, radio, camera and vendor login in one traffic corridor by tomorrow morning?