No WAY is it worse than LA. I drove through LA at 6am many years ago (on my way to start a trip across the country), and sat in stop and go traffic for 1.5 hours. I’ve never encountered something like that in Seattle. Not once.
I would think that LA has dense traffic over a wider area than any other region or metropolitan area. LA is a huge area of you run from San Bernardino to Castaic to the Ocean and down to Irvine and commute traffic everywhere.