With passage of the Energy Independence and Security Act of 2007, Congress raised fuel economy standards for the first time in 32 years. The law also contained a renewable fuels standard requiring production of 36 billion gallons of renewable fuel a year -- which will be mostly ethanol -- by 2022. Together, these two provisions will translate to a reduction in U.S. gasoline consumption of 3.7 million barrels per day in 2025, relative to a business-as-usual scenario.

These are substantial steps toward tackling U.S. oil dependence -- and climate change, too. But looking ahead to what will be needed to meet greenhouse gas emissions goals -- for example, the Lieberman-Warner bill under consideration in the Senate requires that emissions in 2025 be well below 2005 levels -- these vehicle and fuel fixes fall short.

What's missing is a policy to stem the growth in vehicle miles traveled, which has followed from continuing increases in population and per capita driving rates. These increases offset progress from vehicle efficiency and low-carbon fuels, leaving us running in place. In North Carolina, where population and vehicle miles traveled are increasing at substantially more than the national rate, this issue becomes even more pressing. Sensible land use, expanded alternatives to driving and transportation pricing strategies will all be important ingredients of a solution.

Although the federal government is taking steps on fuel economy and renewable fuels production, the same should not be expected for reducing driving rates. "Cap-and-trade" policies (which create a financial incentive to reduce greenhouse gas emissions) and vehicle-miles-traveled fees to raise transportation revenues are both hot topics in Washington. But neither would have much direct effect on driving behavior in the near future. Drivers' sensitivity to the cost of driving has been declining, and the incentive to reduce driving provided by either of these policies at the levels that are likely to be adopted will be small.

So it is crucial that North Carolina take on the challenge of guiding development into land-use patterns conducive to a low-carbon future.

Although the benefits of compact, mixed-use development with good transit accessibility are broadly accepted, states need to adopt policies that will yield measurable results and survive gubernatorial transitions, while helping to deliver on economic and social goals. The Commonwealth Capital Program in Massachusetts, which considers local governments' adoption of good land use and zoning policies in awarding state infrastructure dollars, and California's bill SB375, which would require regional transportation plans to show consistency with state greenhouse gas reduction targets, are among several state efforts along these lines.

In developing a disciplined approach to slowing driving rates, states may be able to draw upon a growing base of support. Already, the demand for housing in compact, transit-served communities is outstripping supply, while demand for large lot housing is expected to fall below supply in coming years. Land-use planning policies will always be contentious, but perhaps the debate going forward can focus on how, not whether, to proceed.