The report (PDF) is part of President Obama's transportation infrastructure proposal. The report calls the president's plan "bold" and says it, "includes a $50 billion up-front investment connected to a $476 billion six-year reauthorization of the surface transportation program and the creation of a National Infrastructure Bank." Revamping the national infrastructure is important, since the report claims that out of every seven dollars the average American earns, one dollar goes to pay for transportation costs.
The Treasury's 1.9 billion number is roughly half as much as an Urban Mobility report found about fuel wasted in the U.S. in 2010, which was 3.9 billion gallons, but we don't know the methodologies used in determining the two numbers. However things were calculated, it's clear that we could use more technologies like start-stop as well as improved infrastructure to minimize traffic jams in the first place. Of course, since researchers have found potential links between traffic jams and autism and brain cell damage, fuel and money aren't the only things we need to worry about when we're not getting to where we want to go.