"While transportation investment always 'creates jobs,' its net effect on workers and the economy as a whole will be positive only if government transportation investments are rigorously selected to meet productivity criteria," according to the report.

The report cautions lawmakers not to authorize any new money for existing transportation programs if the long-range economic benefits are unclear or if those funds are used solely to bolster short-term employment. The report also recommends that funding aimed at increasing employment should be focused on transportation programs that both ease unemployment in the near term through "shovel ready" jobs and advance national economic interests and priorities over the long haul.

Another key recommendation from BPC involves coming up with a transportation policy allowing state and local governments more of a voice in how funds are spent while also spelling out firm outcomes that should result from federal investments.

"Instead of focusing on how the money is spent -- that is, on whether funds go to operations versus capital or to highway versus transit -- the focus must shift to the outcomes being achieved with a particular expenditure," according to the report. "If the most pressing outcomes at this point in time relate to job creation and long-term economic recovery, both of those outcomes should drive decisions about how to allocate federal resources and measure progress."

The 36-page report, "Strengthening Connections Between Transportation Investments and Economic Growth," is available at bit.ly/BPC-Report.