Judith Rodin

is president of the Rockefeller Foundation and former president of the University of Pennsylvania

All of the gas-tax talk has stirred up a storm. Whatever you think about the candidates' proposals, however, their debate has illuminated an urgent reality: If the U.S. government continues with its current transportation policies, it will undermine the social and economic security of our workforce and accelerate global climate change.

We must choose and chart a new course, rebuilding America's overburdened and, in many cases, obsolete transportation infrastructure while addressing these two 21st-century imperatives.

The good news is that we can tackle these challenges head-on - with immediate benefits for our lagging economy. In the short term, "fix it first" strategies can repair existing infrastructure rather than beginning new construction, thus containing our carbon footprint.

The Economic Policy Institute, for example, determined that, within 90 days, the repair process could begin on some of the national highway system's most dangerous bridges for about $5 billion, creating 70,000 jobs.

Over the long run, policymakers must also develop a more comprehensive plan. The Brookings Institution's Metropolitan Policy Program, the Regional Plan Association's America 2050 initiative, the Bipartisan Policy Center, and others are framing a national infrastructure vision.

Pennsylvania Gov. Ed Rendell, California Gov. Arnold Schwarzenegger, and New York Mayor Michael Bloomberg just launched Building America's Future, a nonpartisan coalition focused on advocating best practices and new ideas. And on May 9, in Washington, public officials and business, labor and civic leaders from across the country gathered for a summit, Rebuilding and Renewing America, to draft a blueprint for 21st-century investments.

How dire are the risks? The collapse of the Interstate 35W bridge in Minneapolis in August points to a fundamental crisis. The Philadelphia area alone has about 90 structurally deficient bridges. We all remember when Port Richmond's decaying I-95 bridge span forced a shutdown of the highway in March.

Traffic congestion in 2005 drained $78 billion from our economy, according to Texas A&M's 2007 Urban Mobility Report, adding 4.2 billion hours to Americans' commutes while wasting 2.9 billion gallons of gasoline.

Another critical danger is environmental. The transportation sector accounts for 70 percent of the United States' oil consumption while producing one-third of the nation's greenhouse gas emissions.

Yet the federal government has a backward funding formula: The more a state's residents drive, the more money that state receives.

A less visible danger is economic. Transportation costs are now the second-highest household expense. A 2006 Center for Housing Policy report indicated that low-income, working families in large metropolitan areas spend nearly a third of their incomes on transportation.

A study by the American Public Transportation Association shows the need for investment in mass transit: Two of every three regular users of public transportation earn less than $50,000 a year. The federal government, meanwhile, directs only one of every five gas-tax dollars to public transportation.

We must expand affordable, accessible and environmentally sustainable transportation options: high-speed and light rail, rapid and mass transit, and walkable, bike-able streets. Washington must provide new incentives to promote greener land use, cleaner cars, and decreased automotive dependence.

Regardless of who wins in November, the new president and Congress will come to a crossroads when the highway bill is up for reauthorization next year. We must prepare to seize this moment.

A half-century has passed since President Dwight Eisenhower signed the legislation establishing the interstate highway system. It was a road map for the infrastructure that enabled 50 years of unrivaled economic prosperity and opportunity. Today, we must dare to think and act boldly because the world has dramatically changed.