One of the vexing problems associated with urban sprawl is the associated, call them ancillary, maybe secondary, effects that no one takes responsibility for.

In this particular case, we speak of traffic.

It's a particularly severe problem out near Fresno and Bakersfield, where air quality is famously terrible. One expects smog in Los Angeles and other urban areas, but not in the agricultural heart of the nation. But pollution there is, serious pollution that has a shocking fraction of kids carrying inhalers to school.

As one way to tackle the problem, air pollution regulators, supported by environmental and public-health advocates, suggested that whenever a new housing development is proposed the developer be required to take responsibility for the pollution its development would cause, mostly in the form of increased traffic. This might involve siting the development near public transit, building bike lanes, or, failing all that, paying an extra fee that would be used to reduce pollution elsewhere as a mitigation measure.

The developers howled, as one would expect, but in the latest in a string of legal decisions, the Ninth Circuit Court of Appeals has just ruled against the developers and in favor of people's lungs. Earthjustice represented the Environmental Defense Fund and the Sierra Club in defense of the new regulations, which are being touted as a model for the nation. It's described here in some detail.