If you start in the right lane South bound at the Sno/King line and stay in that lane you come out the South end of Seattle in the left lane. NORTH bound there is NO lane that goes all the way through.
Years ago they wanted to build a foothills freeway around Seattle/Bellevue. Should that done that. Pull the Vancouver, BC to California traffic out of Seattle, ship SE Asia containers to the ports they belong in and Seattle traffic would be much better. Ports are public companies run like private businesses. Why do containers come into downtown Seattle and then get trucked to Vancouver, BC???? Greedy ports compete for business. Rag heads get out of taxis to drive beater trucks up and down I-5.