Heavy-duty truck fleets are trying out alternative fuels and fuel-saving technologies to efficiently comply with government regulations, according to a new study.

The University of Michigan’s Transportation Research Institute conducted a survey with 96 heavy-duty fleet managers who operate a combined total of just over 114,500 truck-tractors and approximately 350,000 trailers. Fleets reported a median of 6.5 mpg, while hauling 2.1 million tons of cargo 10 million miles annually.

These fleets are hauling a total of 9 billion tons of freight across 1.8 billion miles annually, according to the study performed in collaboration with the American Transportation Research Institute, based in Arlington, Va.

Biodiesel blends (B5, B10, and B20) are the most common alternative fuels in use. Every heavy-duty fleet included in this survey currently uses diesel fuel, with biodiesel being an accessible alternative fuel.

While not mentioned in the survey summary, some U.S. fleets are using compressed natural gas (CNG) and liquefied natural gas (LNG) as alternative fuels in heavy-duty trucks. Fleets running medium-duty vehicles are also trying out propane autogas. All-electric and plug-in hybrid trucks are being deployed by fleets in a demonstration test phase, along with renewable natural gas and renewable diesel.

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As for benefits gained by using specific alternative fuels, surveyed fleet managers said the fuels can be lower cost, cleaner (reduced emissions), and more available than other alternative fuels. Disadvantages of these fuels can include little or no infrastructure for distribution and fueling; increased cost overall, and the possibility of lowering overall fuel economy for their fleet.

Fuel-saving technologies are expected to play an important role in hitting federal mandates for fuel economy and reducing emissions. In this study, the common technologies on truck-tractors have been aluminum wheels, speed limiters, and low-rolling resistance dual tires. For trailers, the most common fuel-saving technologies have been low-rolling resistance dual tires, aluminum wheels, and weight-saving technologies.

In August, the U.S. Environmental Protection Agency and the National Highway Traffic Safety Administration released new rules covering greenhouse gas emissions and fuel efficiency for heavy-duty vehicles. The regulations apply to a broad range of vehicles from pickup trucks, to garbage trucks to the largest tractor-trailer rigs on the road. The trucking rules will be phased in over 10 years and take hold in three steps beginning in 2021, followed by 2024 and 2027.

Nearly all fleet managers participating in the study felt that EPA heavy-duty emissions regulations will lead to higher or significantly higher truck operating costs. All of the fleet managers surveyed feel that the federal regulations will lead to higher or significantly higher new truck purchase costs.

Medium and large fleets seem to have more flexibility than smaller fleets in making it work. The smallest fleets included in the study require faster payback periods than medium and large fleets when investing in fuel-saving technologies or when considering switching their heavy-duty fleet to an alternative fuel.

University of Michigan Transportation Research Institute