November 17, 2023:
The extra lanes make no difference at all.
When it was two lanes per direction the heavy trucks locked down the one on the right, holding throughput there to 63 or 64 MPH. Their presence retarded the left lane as well, as drivers crept slowly past them for twenty minutes at a time, averaging 64-and-a-quarter.
Now with more lanes the trucks simply spread out, rolling in parallel in the right two, with the same result, everyone making exactly the same time they did before.
The real kick in the pedal is the ridiculous decision to merge rather than curve. I-101 south from San Jose: the right lane disappears in multiple locations, forcing the merge left. Traffic backs up for miles. It happens again at the interchange with 25 and again with 156. So that the 50 miles from San Jose to Prunedale can take hours and hours and hours.
My favorite of all time is the two-lane exit from 57S to 71S near Puddingstone Lake. In about a hundred yards one lane goes away, forcing a merge; 50 yards later the connector from I-10 merges; so that making it one mile can take 30 minutes at the wrong time of day. Simply converting the exit from 57S to a single lane would solve half of that.
Seemingly all these practices became common in the era before computer simulations. I wonder if anyone would design this way today.