the point is to get people where they want to get to, and the best way of doing that is to provide them with a method of doing so that doesn't waste their lives... you can do something like invest in...better more efficient public transit and move more people, more quickly, without it just turning into a parking lot, which at the same time reduces demand on an arterial.
This is true, give people options that are time competitive with driving and many of them will free up a LOT of space on the roads for everyone else who still needs to drive.
So you can solve traffic congestion on any arterial almost overnight if you wanted to, at very little cost. Just convert a regular lane in each direction into bus lanes, run buses every 10 minutes or better during peak periods, offer both all-stop local and limited-stop express service, make them free or proof of payment to speed boarding, and run the buses 24/7 so you don't get stranded if you miss the last one.
As a bonus, the bus lanes can be used by emergency vehicles at any time, or by everyone in the event of an evacuation (hurricanes on the east coast, wildfires on the west coast, etc.). For this reason, they ought to be considered vital emergency infrastructure.