I was playing around with Census block data and put together a couple of pretty maps. In the maps below, the darkest brown (e.g. the dark spot in downtown SF) represents census blocks with at least 100 residents per acre. Lighter orange colors are in steps of 30, 10, 3, and 1 residents per acre. Both are scaled at 1:300000.
An entirely different urban form. It’s difficult to imagine the public transportation network that could effectively connect this enormous territory.
By the way, almost 22% of California’s population lives in census blocks with more than 30 residents per acre — that’s the 3rd highest fraction in the U.S., behind New York and Hawaii — and you’re seeing most of them in these two maps.
Data: I grabbed the Census data underlying these maps here, and processed/mapped with QGIS. I wanted to make a population density map of the entire U.S., but the state shapefiles are already enormous enough (almost 700 MB of data for California alone).