I cross the Interstate 5 Bridge in a semi-truck several times a day. Traffic jams mostly occur on the approaches to the I-5 Bridge, not on the bridge itself, barring someone's "breakdown" whilst crossing. Once on the bridge traffic accelerates steadily and zooms upon leaving the bridge, a.m. and p.m. both. Approach slowdowns only last a few hours during peak traffic. Most of the bridge's day/night traffic volume is unremarkable and flows smoothly.
Adding another lane southbound in the a.m. and northbound in the p.m. would ameliorate the bridge approach slowdowns. The new proposed Columbia River Crossing does not add such lanes. Why not institute a reversible lane system during peak traffic? It worked very well in Seattle on the Interstate 90 floating bridge and tunnels, as well as on the I-5 approaches to that city's core, handling a lot more traffic than we have here. Why not give it a try, avoid permanent tolls, and save our dollars for some other ill-conceived public venture?
We all know that the real traffic choke point lies nearer the Portland core, miles from Clark County.