By one estimate, making just basic fixes to the nation's roads bridges, mass transit and water facilities would cost $1.5 trillion dollars.
"we have to make sure that the stimulus is significant enough that it really gives a jolt to the economy ," Obama said.
Monday, the president-elect did not offer specifics on how his infrastructure-job creation program would work or what it might cost. He wants to wait for his new economic team to make recommendations, but it is clear that the Obama administration will want a plan before Congress within weeks of taking office.
"Obama's plan is looking for strategic investments that show they have public payback. State and local governments have to demonstrate they have a clear public benefit that can be measured and analyzed in exchange for federal funds that wouldn't have been available in the past," said Joe Schwieterman of the Chaddick Institute - DePaul University.
Big public works projects are often larded with red tape and take a long time to start, but the Washington-based Public Works Association says there are 3,600 public works projects nationwide- from bridge rebuilding to sidewalk repair - that could be started inside 90 days, and that could jump-start job creation.
Another emphasis is on creating 'green' jobs through retrofitting energy inefficient buildings and through a heightened emphasis on wind and solar power. Enacting a national renewable energy policy would lead to more turbines and solar panels.
"That will drive more wind power development. Our electric companies will be buying more wind power, and that will drive the providers, and that will provide more operating and more technical jobs," said the Environmental Law and Policy Center's Howard Learner.
What will it all cost, and how do we pay for it?
The president-elect said Monday that the right answer to those questions is to first get the economy back on track with some long-term sustainable solutions.
During his campaign, Obama said he could support an economic stimulus plan costing in the neighborhood of $175 billion, but the economy has darkened since then, and that number most certainly has gone up.