A public good that does private harm.

It's very easy to plug numbers into numbers and get numbers. This is one of the reasons few people consider externalities. They are the numbers that don't have numbers so they tend to get hand-waved away. By your math, saving 45,000 cars a day saves the city, at large, $15k a day. 'k. More simply put, it saves 33 cents per person on the road. How many people are there in the neighborhood? Let's say there's a thousand for magical, easy math. Do you think they'd trade $15 a day to have their neighborhood back? That's $5k a year. Probably a healthy chunk of their property taxes.

Do you think they're entitled to throw up a 30-cents-per-car toll booth?

I'll bet you don't. After all, they didn't build that road. But their property taxes paid for it. Everyone's property taxes paid for it. Thing is, their property taxes are related to the assessed value of their homes, and having a constant stream of commuters is kicking their property taxes in the nuts. How much? Well, externality. Hard to say. How much is due to the bad roads? how much is due to the increased pollution? How much is due to the assessor fearing for his life as he tries to cross the street?

That's just the semi-easy stuff. What are the public health costs of having the air pollution that much closer to homes? The increased noise? The decrease in safety? Harder to put a number on, but no less real.

But all those people on Waze are going to flip their shit if someone builds a lemonade-stand-style toll booth because our freedomz.

I shouldn't have to argue that urban planners know better. That's what they do. They plan. There WAS a freeway planned through Beverly Hills. It would have done exactly what you wanted - "flow like water down the path of least resistance." The rich people won and the Westside is a neighborhood. The poor people lost and Commerce/Downey/et. al. are a wasteland.

I can honestly say you don't know what you want. Splitting time between LA and Seattle, you get to see two visions: the "build roads everywhere" apocalypse and the "please god let's not turn into LA" congestion.

Congestion is better.

Thirty cents a day to save two minutes. What does that buy in vanpools? What does that buy in bus routes? What does that buy in mass transit? What does that buy in bike lanes? What does that buy in planned public benefits instead of free-market predation?

You could have gotten your wish.

Take a peek out the window as you cross the 520. That should have been six lanes through the arboretum. Think about traffic that "should flow like water" and then click around.

You might think you want to live there. Me? I've crossed under the 405 on bicycle and I can tell you unequivocally that I do not.