The transportation sector is a major part of the climate change mitigation challenge, accounting for approximately 28% of all annual GHG emissions in the United States. The FTA has responded to the need to reduce GHG emissions by creating new funding programs for purchase of low carbon vehicles. FTA has also conducted research on strategies for transit emissions reductions. This work builds on prior work that was supported by the FTA. The Transit Greenhouse Gas Emissions Management Compendium was an informational guidebook developed to assist transit agencies with managing their GHG emissions . It contained information to educate transit agencies on potential GHG emissions reduction strategies, presented case studies of successful GHG emission reduction practices, and information on emissions quantification methods. The Compendium showed that the combustion of fuels for the propulsion of transit vehicles constituted the greatest source of GHG emissions from transit agencies. Therefore, improvements in the GHG emissions performance of transit vehicle fleets can be made through the procurement of more carbon efficient vehicles and fuels. The fleet procurement process represents a critical opportunity for reducing much of the day-to-day energy consumption and GHG emissions of transit agencies. The GHG Calculator Tool was developed as a follow-up to the Compendium to aid the transit industry in making vehicle decisions and managing fleet in the most responsible way that is both environmentally and economically sound. In addition, Brent Weigel, a student at Georgia Tech created the original Calculator for Estimation and Management of GHG Emissions from Public Transit Agency Operations as his 2010 Master of Science Thesis). This thesis project produced an excel-based calculator which represented average emissions from transit operations, including upstream lifecycle emissions, fuel chain emissions, and on-road emissions from average operations.

The current FEC is developed in order to make various improvements to the spreadsheet calculator first developed by Brent Weigel, drawing on understanding gathered from compiling the Compendium as well as additional work that was being conducted by Georgia Tech professors. Key considerations for updating the Greenhouse Gas Calculator were to add: new vehicle types and propulsion technologies, and the capability to estimate energy consumption and emissions effects from changes in on-road operating characteristics including route length and stops (duty-cycle), grade. The detail of FEC will be provided in the following sections.