Sprawl IS a new phenomenon, though. We didn't see the kind of suburban sprawl that we see today until after WW2, when cars became THE way to get around. It became more and more dominant and entrenched as the interstate highway system developed.

Remember, we're talking about relative density within a metro area, not how close each metro area is to the others. If you look at cities that were more or less fully developed prior to WW2, like Boston, you find that they're more compact, as opposed to, say, LA or Phoenix.

That said, I don't think it's the only thing making us fat. But I do think it's one contributing factor.

True, but even in Boston they can't get public transportation and infrastructure right. Boston is almost certainly one of the most vibrant economic hubs in America and one of the most compact cities, but the subway absolutely sucks, is completely outdated, and can't adequately service proximal cities like Somerville. The city is also desperately in need of further tunneling and infrastructure expansion to service the Cambridge / Somerville area as well as the Sea Port but I can't see that ever happening. It's taken us over five years to fix a single small bridge with two lanes in each direction...

When I read about proposed public transit projects in Boston that were never built, most of them had actually been _court mandated_ by the Big Dig mitigation lawsuits, but they still didn't get completed. Very mysterious.

To be fair about the 'single small bridge', it seems like smaller projects suffer proportionately larger delays due to being considered low priority, ridiculously lax work scheduling, etc. Although the financial scales are completely different, it takes my city (Toronto) approximately the same time to build a subway extension as to renovate the bike trail that runs near my house.

This single small bridge, the Longfellow Bridge, is a crucial artery connecting Boston with its surrounding cities and towns across the river. I should have emphasized in my initial comment that it is a high priority project.

The patterns of the LA basins development was set by the Pacific Electric Railway, in the 20's and 30's - the freeways if you look almost all parallel former PE lines.