| As the United States moves closer to regulating greenhouse gas (GHG) emissions in response to global climate change, solutions are needed that minimize the cost burden on consumers. The on-road transportation sector, which accounts for one-third of US GHG emissions, may be a likely candidate for significant reduction of GHGs. While vehicle and fuel technology increasingly limit the release of other tailpipe pollutants, transportation-based GHG emissions have continued to rise, as the number of total vehicle miles traveled (VMT) has risen. At the same time, the Federal Highway Trust Fund, the source for most Federal surface transportation spending, suffers from a substantial financial crisis. Directing transportation investment into a cost-effective means of significant VMT reduction would help alleviate pressure on the Trust Fund, as well as, abate US GHG emissions. This study looks at the potential of VMT reduction from the Congestion Mitigation and Air Quality (CMAQ) program, as a means of reducing GHG emissions with a particular focus paid to its funding of infrastructure for transportation modes, other than single-occupancy vehicles. While it was determined that VMT grew at a slower rate in metropolitan areas that received more alternative transportation funding, the findings were not significant enough to definitively state the effectiveness of CMAQ as a GHG reducing mechanism. There are two possible reasons for these findings, one practical and one statistical. The practical reason may be that the programs are so small relative to overall system expenditure that only larger programs would produce a real impact. The statistical reason may be that the funding amounts are so small relative to overall VMT that other factors dominated in the statistical regressions. However, the results also do not rule out the ability of concentrated alternative transportation spending, as in CMAQ, to influence VMT growth. |
