Smarter Highways For Seattle
In case anyone else has been wondering what the black boxes above SR 520, I-90 and I-5 were…
First, no, they don’t take your picture, have lasers, or mail you tickets. The black boxes hovering precipitously above the highways are there to help with traffic. They are Active Traffic Management tools. They are essentially a series of electronic speed-limit and lane status signs that will adjust automatically to help highway-goers navigate with a higher degree of safety and efficiency.
Using Technology Improves Traffic
Active traffic management tools have been proven to be effective at reducing collisions and improving traffic flow in Europe. The use of the technology has reduced collisions by around 30% and increased the total traffic capacity on the roadway.
The goal is to utilize the traffic management signs to reduce congestion and help make travel safer and efficient.
For more information, please see the WSDOT web page for SR 520 and I-90 active traffic management.





