A new Washington Policy Center report investigates the oft-cited claim that a light rail project in Seattle will improve the environment and reduce carbon dioxide emissions. Interestingly, the report notes, “no studies have actually been done to test that hypothesis here in Washington. When attempting to find the source for this assumption, no [government] agency we spoke with had begun this type of analysis, although all claimed that it was in their future.”

“Light Rail on I-90 Will Do Little to Reduce CO2” was written by Todd Myers, director of WPC's Center for Environmental Policy. Myers writes, “[u]sing a model provided by the California Air Resources Board (CARB), we tested the CO2 emissions of both the light rail proposal and the ‘no action’ alternative which would leave the current I-90 configuration.” One of three key findings: “The CO2 reductions achieved from light rail can very easily be matched by a small increase in fuel efficiency.”

The author cautions that emissions from the construction process can offset gains:

[W]hile the data show a slight reduction in day-to-day emissions of CO2, it is probably not reasonable to make light rail the centerpiece of any strategy to reduce greenhouse gases. Our focus in this study is on the day-to-day emissions and does not account for the greenhouse gases emitted during the construction process from the many tons of concrete, steel and other elements of the construction process. An average daily reduction of six percent is likely to take an exceedingly long time to offset the CO2 emitted during construction.

“Light Rail on I-90 Will Do Little to Reduce CO2” was published in Sept. 2007, the same month as the Journal of Urban Economics article, “On the Social Desirability of Urban Rail Systems.” The research by Brookings Institution transportation policy expert Clifford Winston and University of California- Berkeley economist Vikram Maheshri dovetails with that of the Washington Policy Center.

For a synopsis of “On the Social Desirability of Urban Rail Systems” see the review, “The Train Drain,” by Robert W. Poole, Jr. Poole is director of transportation studies at the Reason Foundation.