[wpietri]

And even if they somehow do manage to do it, I'm not sure at all that any lasting improvement will be made. An urban planner friend tells me that people decide where to live based on commute time, not miles driven. So if you put in more roadway, people move to cheaper places farther out, using more road-miles than before, at least until the speeds drop back down. 

[nitrogen]

Isn't that just a sign that people need better housing options?

[wpietri]

I'm not sure what practical intervention you're suggesting there. We can rebuild existing buildings to be denser, but I'm not sure how you'd make that cheaper than a new suburban home, let alone as appealing to the kind of person who currently buys a new suburban home.