The problem with Portland traffic isn't the amount of lanes. You have to view freeways like blood viens, from 1100 to 1900 Portland and thus Vancouver is a clogged artery. The only way to relieve, you will not compleatly get rid of congestion, is to build a a 3rd freeway that starts jus tnorth of Vancouver and ends/starts just south of portland. This freeway will have zero on/off ramps and be just a through way for traffic going norht and south, I-5 is one of our busiest Interstates. This freeway would have to be elevated, most likely above I5. This would take a lot of money and time and cause massive delays and headaches during the construction.