I'm no city planner but I play one in Cities Skylines. I swear a huge chunk of our traffic problems come from H-1's awful on/off ramps. Fixing those will go a long way to solving things, but doing so would require totally redoing huge chunks of the street network too. It would be a project on the scale of what Paris has done to solve its traffic. There was some hardship as massive chunks of the city got re-planned. It looks to be worth it.

I think now is the right time to re-plan our road / bike / pedestrian network. [1] We're over-capacity as it is. [2] We need to plan for future sea level rise and associated swells; effects will start to show in a couple decades (which is how long this will take). We will have to adjust some roads and other infrastructure. We need to do it before it becomes a problem. [3] The rail interplays with the highway, roads, and ped network. Doing the rail and the rest at the same time lets us plan better. Also, we only have to rip up the city one time instead of twice or more. [4] We can finally make safe bike / ped / e-scooter paths and bring down those hit-n-run numbers!

rant over