I was also involved in planning & environmental work for some of the LA-area grade seps.

LA Basin counties (mostly LA & Orange, though more recently San Bernardino & Riverside have started programs) have been willing to tax themselves substantially to improve transportation. Yes, there's grumbling & griping from the anti-tax crowd, and issues with exactly what gets built when, but those programs and the ACE projects are doing a job that would never get done with just state & federal money. That area has stepped up and is helping themselves, and their kids and grandkids should thank them. Other areas of the state - not so much with a few modest exceptions.