Electrification of Transit Buses in the United States Reduces Greenhouse Gas Emissions

In 2021, President Biden signed the Bipartisan Infrastructure Law to revitalize the nation’s infrastructure. This law included $5.6 billion in grants to reduce emissions from public transit   by buying buses with low or no tailpipe emissions. New peer-reviewed research led by Sofia Martinez, a Ph.D. student in Civil & Environmental Engineering, analyzed the effects of transitioning the entire U.S. transit bus fleet to battery electric buses.

“We chose to focus on transit buses since they are a mode of transportation that anyone can use, and they often operate in cities where air pollutants and noise disproportionately affect disadvantaged communities,” Martinez says.

Her research with CEE Professor and Director of Scott Institute for Energy Innovation, Costa Samaras, was recently published in the journal Environmental Science and Technology titled, “Electrification of Transit Buses in the United States Reduces Greenhouse Gas Emissions”.

Martinez’s research focuses on the approximately 70,000 transit buses in the U.S. She found that transitioning the transit bus fleet under a number of different scenarios would mitigate between 33% and 65% of existing bus emissions—even when accounting for the emissions associated with the electricity used to charge the buses and the impacts from manufacturing the batteries.

“Our work also included a levelized cost of driving that shows that when you account for the social costs of the carbon mitigated, the battery electric buses can actually be less costly to society than diesel buses," says Martinez.

Martinez believes that her research will help encourage more transit agencies to electrify their bus fleets. “Public transit is a simple solution to many challenges such as traffic, air pollution, and greenhouse gas emissions. Modernizing and making transit more accessible and sustainable is how we can encourage broader adoption.”