I think it's unfair to blame the construction of modern neighborhoods. It is the current technology that feeds the sedentary lifestyles.

The convenience of a nearby store can certainly increase a person's transportation habits. However, the amount of local stores has been in decline for several years. Improvements in transportation and communication have allowed for more spread out chain-stores (such as Wal-Mart) to take over.

This change in shopping methods is due to the demands of current society. It is the trends of the consumer that evolve the culture. Those who can afford a car and a house and in suburbs follow these trends as companies shift their focus. The suburban neighborhoods were built to accommodate to this change.

I should be noted that one of the reasons New Urbansim became so popular was because developers are willing (and eager) to build these communities. While there are great things about walkable cities (nobody talks about walkable suburbs) from a developer's perspective they can sell smaller lots for the same amount of money as a larger lot under the banner of making things more "walkable".

But it doesn't matter, because very few people that live in these communities walk anywhere at all. Since there aren't any big points of interest inside a suburban real estate development everybody just drive out anyway. Killer Cul-de-sacs is just clever marketing, nobody is out there tearing them up, they just build new developments and its much easier to get people to move in when they don't like their old street.

In other words, just because urban designs correlate with travel behavior, it doesn't mean they cause it.

This view is partly true.

Urban design does cause massive changes in travel behaviour, it's just that urban design isn't the only factor causing change in behaviour. Money and time are the two biggest other factors. You try making that highway more expensive (toll booth) or reduce its efficiency, and people will immediately search for different routes to work. But getting people to change modality (mode of transport) takes an astronomical effort.

People are creatures of habit. Good luck getting those 300-steps-a-day Americans out of the car. Not only does it take a reliable, faster, more comfortable mode of transport (e.g. the Lightrail hype currently), you also need to change their daily rhythm. It is far easier to create an excuse for inaction than a convincing case for action. A train could save time, effort, environmental footprint and still people will dismiss it entirely 'because trains are for poor people' or whatever small excuse they come up with.

The article addresses one of the big questions in planning: how does the built environment change behaviour, and more interestingly, how do we make changes in the design of cities to change behaviour for the better? What is 'better', for whom? These questions don't have straightforward answers, as there are just too many variables to take into account. But single-zone land use has had its day. Large commercial, industrial and residential districts only forces people to travel by car. Combine it with low density and you have the deadly cocktail that degrades not just health as the title suggests but also relationships, time, etcetera.

You only need to travel to get something that isn't where you are. So if you have your daily needs (work, school, shops) around the corner, like in the Atlantic Station example, you won't need your car. And since there are no pre-existing habits when you move somewhere else, it's easy to forget about the car altogether.