The impact of light rail on congestion in Denver: A reappraisal

In a recent analysis, Bhattacharjee and Goetz (2012) assert that the development of a light rail system in the Denver, Colorado metro area resulted in short-term reductions in traffic on some highway routes in Denver, and that it reduced the growth of highway traffic on major highways near the light rail network by 10% age points between 1992 and 2008. We point out several flaws in their analyses and reanalyze their data. We find no credible evidence that development of light rail reduced highway traffic, nor that it reduced the growth of highway traffic. We also show that light rail, by a large margin, carries too few passengers to have the effect that they assert.