Hard for me not to chime in on this... I've felt for many years (and this feeling is only getting stronger and stronger) that the number one issue facing this country, possibly the world at large, is suburban sprawl. Possibly a bit hyperbolic. But I could write a book, in fact many have (see Green Metropolis or Walkable City) that you can directly draw a line from sprawl to obesity, heart disease, global warming, our various wars in the middle east, many senseless car accident deaths, strains on local governments, income inequality, etc.
Now, the problem with thinking this way is that many people live in the suburbs and being one that doesn't that quite frankly hates them and hates cars is that you come off as a pretentious, know-it-all asshole and people get rather defensive. This thread, although some of the arguments made were slightly different, is a decent case in point (it does seem everyone made nice though, which is good).
I'm hoping situations and articles like this start to change the conversation for the greater good. Suburbs to me simply mean places built around cars versus places built around pedestrians and transit. It doesn't have to be about cool, chic downtown versus quiet, boring what-have-you. This isn't about finger-pointing, at least not all the time, it's simply about city planning, how and how much public investment is used, how federal subsidies support oil and a car-based model, how outdated zoning regulations make density difficult, how parking requirements for new buildings get in the way of better development...
Anyway, I hope some good can come out of this terrible incident and the problem at hand can be looked at as more of a system and as less of an indictment of individual choices.