Gray boxes, holding the wiring for nearby traffic signals, dot more than 1,000 intersections throughout Seattle. They fade into the background by design, many of them further camouflaged with graffiti and posters for candidates or concerts.

It would be no surprise, then, if you’ve missed a new accouterment added to many of these boxes in the last year: a small rubber antenna, like a lily pad or tiddlywink, perched on top.

The antennas are a patented design from Skywave Antennas in Huntsville, Alabama. Each is connected to a modem that casts a net of Wi-Fi across the intersection. As you approach, the signal pings not only the sensors in your car, but your phone and tablet as well. A succession of these gizmos can track your progress down the street.

It’s another step in Seattle's march to the future, a world where the street grid adapts to congestion, construction, accidents and football games in real-time. And as the city works to build a framework for vetting new technologies, struggling at times to keep pace with the speed of technology, it is also driving privacy advocate nuts.

Seattle's street grid is packed beyond its capacity. The city recently ranked 7th worst in the country for congestion. Because of geographic constraints, however, building more roads is really not an option. That leaves either getting cars off the road or allowing them to move more smoothly through the system -- and that means making the traffic grid a smarter place.