By James Rubin, PhD, Principal and Performance Management Lead
Brendan Morgan, Senior Project Analyst
TransDASH is our platform for a collection of public transportation agencies of varying sizes across the United States to measure their performance and display the value transit operations provide to their region. Transit operations provide value to its region in many different areas, but one that has been a focus lately is climate contributions. The major question posed to transit agencies is whether their contributions to greenhouse gas (GHG) emissions through operations exceed the reductions in GHG emissions made by customers eliminating trips from their personal vehicles by taking public transit. With this question in mind, we have worked with the TransDASH cohort over the past 12 months to research, develop, and agree upon a process to internally estimate GHG emissions utilizing publicly available data sets and internal agency data.
To inform our process, we researched recommended practices from both APTA and The Climate Registry, as well as industry reports estimating transit GHG emissions. Through this research, a standardized process to estimate transit GHG emissions was recommended to the TransDASH cohort, which is currently undergoing a trial run. Collaborating with participating TransDASH agencies, we are gathering internal data sets such as fleet fuel usage, facility energy usage, and other operational metrics to estimate their CO2 emission contributions in the targeted fiscal years. Alongside the internal operational agency data, we are also utilizing public data sets such as mode shift factors, estimated fuel economies, and CO2 equivalents to assist in our analysis.
With access to these internal and external data sets, we can estimate the quantity of CO2 emissions contributed by transit operations and the quantity of CO2 emissions avoided by eliminating personal vehicle trips and taking public transit instead. Additionally, efficiency metrics have been established, which will allow for the comparison of estimated CO2 emissions among different modes or even different routes within the same mode. Finally, customers in the region can better understand how their public transit trips impact the environment by knowing the quantity of CO2 emissions produced per mile of riding different transit modes as well as how many personal vehicle gas dollars have been saved by riding transit.
While we are in the initial phase of running this analysis, as the years go by, we will be able to understand better how GHG emissions are shifting based on the recent trend of fleet electrification. This can also be analyzed to understand whether the implementation of cleaner fleet technology is being distributed equitably across the region to ensure lower-income communities are not disproportionately affected by GHG emissions from transit operations. With the complexity of climate change and the multitude of factors at play, we are just beginning to understand transit’s value in improving each region’s climate.
