The State of Sustainable Fleets is an annual report that gathers real-world data directly from early-adopter fleets across the U.S. to provide deep sector-specific insights into the adoption of natural gas, propane, battery electric, and hydrogen fuel cell electric vehicles, against a baseline of diesel and gasoline vehicles. The analysis includes public, private, and for-hire fleets, including school, municipal/shuttle, urban delivery, refuse, utility, transit, short-haul, and long-haul sectors. This first-of-its-kind report includes unique insights into vehicle sale trends, anticipated vehicle development timelines, real-world infrastructure and fuel costs, and the growing adoption of renewable fuels.