This is my view of Seattle. Unbelievable traffic both on the freeways and in town. We left Boeing Field at 4:00pm (rush hour) and headed south on I-5. We spent nearly three hours going a total of 40 miles. I am sure that I would get more traffic savvy if I lived there. I don't intend to live there. Since Agent Listorama's cover is a retired person, he can go when he wants and doesn't have to contend with traffic. We are the same way in Houston.
You should have waited three hours before using southbound I-5. The congestion around here is awful. It's nice to have the luxury of deciding when to hit the road, but having to plan one's driving around rush hours is depressing. Eastbound Interstate 405 between Tukwila and Renton starts getting busy around noon and stays that way all afternoon. Bummer!