A Comparative Life-Cycle Analysis of the Dulles Corridor Metrorail Project's Associated Greenhouse Gas Emissions

Abstract

Evidence suggests that rail travel consumes less energy and emits less carbon dioxide per passenger mile than traditional car travel. Few cities with rail are able to successfully convert travelers from car travel to rail, negating this benefit. A rail line with the potential to successfully convert car travelers and provide a net emissions benefit is the Dulles Corridor Metrorail Line in Tyson's Corner, Virginia. A life-cycle analysis was performed on the Dulles project using parameters established by scholarly literature. Project specifications and data were obtained from the contractor, Dulles Transit Partners, to quantify the life-cycle emissions associated with the construction and operation of the project. A probable ridership conversion rate and estimate of miles of car travel saved were calculated using national travel and emissions standards. A life-cycle analysis of the saved car travel was performed to quantify the emissions prevented by the use of rail. The overall emissions impact of rail travel to car travel was compared. The required conversion percentage to cross the net-zero emissions threshold is reasonable and could feasibly be achieved at this location. The comparison performed provides both positive and negative environmental impacts that would be valuable climate-centered additions to Environmental Impact Statements.