I absolutely agree that better city and development planning will be essential to deal with this problem. The trend of building huge residential-only developments where residents have to drive everywhere to do *anything* (work, shop, etc.) has surely created massive amounts of traffic.
However, I suspect that even if we are successful in promoting mixed-use developments so people can, in theory, live near their jobs, it will have much less impact on traffic than we would hope. For much of the 20th century, it was typical for only one person in a household to work full time. Today, though, both partners in middle- to lower-income families often must work full time just to make ends meet. Because of wage stagnation, today's two-income families actually have less discretionary income than comparable single-income families of a few generations ago. And, of course, many people want to have their own career regardless of what their partner does.
The consequence is that efforts to eliminate commuting through intelligent urban planning would probably have been far more successful in the '50s and '60s than they could be today. For many couples with two careers, it just won't be possible to live where neither person has to commute. Furthermore, couples often decide to live somewhere that is approximately equidistant between their two jobs so that neither person has to carry the full commuting burden. Thus, you still end up with two cars on the road every day, and better city planning seems unlikely to change that.