Last week in New Hampshire, and this week in South Carolina, Mitt Romney fielded questions about our deteriorating infrastructure. This is an important environmental issue, since potholes and traffic don’t mix well. Consequently, you get more congestion on our roads. And congestion means idling engines and more pollution. It’s also important to maintain and expand public transportation such as commuter rail, especially in our growing metropolitan areas. According to a recent Brookings Institution analysis, while 70 percent of residents of metro areas have access to public transportation, a paltry 30 percent of jobs in those areas are transit-accessible.

Transportation investments attract support on both sides of the aisle, as evidenced by a recent bipartisan letter from more than 110 House Members to President Obama. And the President himself has in turn urged Congress to get to work on this issue, flanked on the left by the AFL-CIO and on the right by the Chamber of Commerce. He and his Administration have also been promoting much-needed investment as part of the American Jobs Act proposed this year, as a Treasury official describes in a blog entry here.

The truth is that we need to invest in transportation in order to compete economically and to reduce pollution from our fleet of cars and trucks. However, proposals that are scaled to address the challenge, such as former House Transportation Committee Chairman Jim Oberstar’s 2009 Surface Transportation Authorization and the proposal described in some detail in President Obama’s originally proposed 2012 budget, have never been seriously debated (in fact the President never officially released a transportation bill).

This is simply inexcusable. Efficient, effective transportation is essential for lifting the economy out of the doldrums and (literally) keeping it moving. And a well-designed new program would cut wasteful spending on environmentally damaging bridges and highways to nowhere while boosting investment in oil-saving public transportation projects. This would double-down on the remarkable progress the current Administration is making to reduce our dangerous oil addiction by raising the bar on auto fuel economy performance.

The question is where all the candidates stand on transportation infrastructure. We need a new transportation program – the old one expired more than two years ago – and soon. Time for everyone who wants to be President to tell us exactly how they’ll fix our roads, bridges, and rail lines, so we can get America back to work.