The Seattle metro is a unique situation that exists outside of just city planning...we are trapped between various lakes, mountains ranges, and massive bodies of saltwater - and I don't say this in the regions defense - I have suffered an insane commute here before choosing to make the sacrifices necessary to live and afford to live in the city. At the same time the things that make commuting in this place difficult are what make it precious.
Hopefully ST3 comes to fruition as there simply aren't many more places to put highways.
Adding highways isn't the only tool available to transportation planners. Isn't it interesting how some intersections bog down at any capacity, while others are busy and still keep moving smoothly?
There are types of lane and intersection designs which never seem to work well, and I'm surprised that more isn't done to avoid or eliminate them.
Hopefully ST3 comes to fruition as there simply aren't many more places to put highways.