The seventh annual State of Sustainable Fleets report lands as fleets face one of the most uncertain environments in decades.

Tariff disruptions, regulatory reversals and a prolonged freight recession have suppressed new vehicle orders across every drivetrain. Federal policy shifts erased the previous federally driven push toward zero-emission trucks. The rollback of greenhouse gas vehicle standards, expiration of commercial zero-emission vehicle tax credits worth up to $40,000 per medium- and heavy-duty unit, and nullification of California’s clean truck regulations left fleet managers unsure what to order next.

Available funding for clean projects still exceeds pre-Biden levels. There remains more than $5 billion flowing annually from state, local and utility programs through 2028.

California alone held roughly $1 billion in grants for on-road trucks and buses last year and reserved $592 million in vouchers for 3,569 Class 2b-8 zero-emission vehicles through its Hybrid and Zero Emission Truck and Bus Voucher Incentive Project.

Natural gas engines saw growth. The Cummins X15N 15-liter natural gas engine finished its first full commercial year with diesel-like performance and clear cost wins. Among fleets running the engine, 71% reported savings versus diesel and 59% versus other natural gas vehicles.

Battery electric also delivered on savings. Medium- and heavy-duty battery-electric vehicle registrations rose 21% in 2025. Fleets operating medium-duty BEVs said the trucks delivered lower operating costs than the vehicles they replaced.

Read more: FreightWaves