The fleet industry is witnessing rapid advancements in technology, sustainability, and regulatory landscapes. The TRC's State of Sustainable Fleets report highlights a growing momentum towards clean technology adoption. While regulatory confusion persists, especially with a focus on zero-emission vehicle (ZEV) regulations, fleets are actively planning their transitions to eco-friendly alternatives. Diesel vehicle sales surged in 2023, alongside a notable uptick in renewable diesel fuel consumption. Renewable natural gas emerged as a popular choice among fleets, supported by the opening of new production facilities. The report also highlights a significant increase in medium-duty battery-electric vehicle (BEV) deliveries, showcasing a promising shift towards electrification. However, infrastructure challenges pose a hurdle for widespread adoption, especially outside California. Additionally, the hydrogen economy gained attention in 2023, driven by federal investments in hydrogen production and infrastructure. Despite cost challenges, OEMs like Nikola and Hyundai are introducing hydrogen fuel cell EVs to fleets, signaling a potential shift towards hydrogen-powered vehicles. The industry recognizes the need to overcome infrastructure obstacles to fully leverage the benefits of hydrogen as a clean energy option in the future.