This is the Oakland bay bridge. The lanes only expand to this wide to accommodate more toll booths. Because cars move slower on lanes when they are paying tolls, the tolls will become a bottleneck unless there are more toll lanes than highway lanes. You can see up ahead where the lanes merge back together again.

This is the only direct road connection between Oakland and San Francisco, so of course there will be heavy traffic no matter how much public transport you have. And the bay area has decent public transport by american standards, which isn't saying much, but many people live close to commuter rail.

I don't see the problem with this, there are much worse examples of modern car infrastructure imo.