In a move that should've been taken eons ago, California's legislature is moving to bring civic planning under a unified framework that will reduce carbon emissions and reduce traffic:

The bill yokes three regulatory and permit processes. One focuses on regional planning: how land use should be split among industry, agriculture, homes, open space and commercial centers. Another governs where roads and bridges are built. A third sets out housing needs and responsibilities — for instance, how much affordable housing a community must allow.

Under the pending measure, the three regulatory and permit processes must be synchronized to meet new goals, set by the state’s Air Resources Board, to reduce heat-trapping gases.

Seventeen regional planning groups from across the state will submit their land-use, transportation and housing plans to the board. If the board rules that a plan will fall short of its emissions targets, then an alternative blueprint for meeting the goals must be developed.

Once state approval is granted, or an alternative plan submitted, billions of dollars in state and federal transportation subsidies can be awarded. The law would allow the money to be distributed even if an alternative plan fails to pass muster.

Encouraging higher density of development, and mixed use development, would also spur wider adoption of public transit, and make it easier to expand public transit to new areas. That would further reduce traffic, as well as carbon emissions. And once you have light rail or a subway system running somewhere, it signifies a long-term commitment to transit-friendly building. That encourages local grocery stores to open and serve a clientele that shops on foot, by bike, or by bus. It changes how people relate to one another, and how they think about travel.