In February, Congress passed a $787 billion stimulus package—the American Recovery and Reinvestment Act (ARRA)—which included substantial new funding for infrastructure investment. From a macroeconomic perspective, this is good news: infrastructure spending as economic stimulus provides a high economic “bang-for-the-buck” (that is, extra output and employment created through each dollar increase in the federal deficit) and stands near the top of the list of proposals to spur economic recovery.¹ The largest chunk of this investment focuses on transportation infrastructure, which is likely to provide even more bang-for-the-buck than generic infrastructure investment.