Often when we talk about decarbonizing trucking we focus on alternative fuels. The reality is if we’re going to get to a zero-emission freight future, we will have to focus on alternative fuels. But the road to zero is long and so we should not discount strides that we can make with diesel-powered trucks.
We have made significant strides in decarbonizing diesel trucks. The 2024 NACFE Fleet Fuel Study showed that the fuel economy of the studied fleets reached 7.62 in 2022 and 7.77 in 2023. This was a year-over-year improvement of 4.2% and 2.0% respectively.
The Fleet Fuel Study looks at the fleet adoption rate of 86 technologies that improve freight efficiency. This includes things like aerodynamic devices for both tractors and trailers, idle reduction devices, tire pressure monitoring and inflation devices, low rolling resistance tires, 6×2 axles and more. For the study, 86 technologies and practices were grouped into seven categories: tractor aerodynamics, trailer aerodynamics, powertrains, tires/wheels, idle reduction, chassis, and fleet practices
The fleets in this year’s Fleet Fuel Study saw adoption of the studied technologies range from having about 22% to 59% of the available technologies in use on their tractors and trailers. The maximum adoption rate by a fleet would be around 65%, depending on the set of technology combinations since some technologies are competing solutions for a single function. For example, a truck would not have both a diesel auxiliary power unit and a battery HVAC system.
And the fleets that participated in the study are not the only ones with higher MPG numbers. The average fuel economy for the industry was 5.85 MPG in 2013 and in 2022 it was 6.91. (This is most recent year for which data is available from the Federal Highway Administration.)
The study fleets were more profitable on every truck by $6,831 because of reduced fuel cost versus the average combination truck in the U.S., assuming the trucks were accumulating 100,000 miles per year and using the average cost of fuel in 2022. At the five-year average cost of $3.62 per gallon, the savings were $4,956 per truck. All combined, the 15 fleets in the study operating 75,000 trucks saved $512 million in 2023 compared to the average truck on the road.
It is important to note that these fuel economy improvements are happening at a time when we are seeing a shift to more regional haul and hub-and-spoke operations where length of haul is getting shorter and includes more urban and stop-and-go driving. Those driving conditions tend to lower MPG, but the numbers put up by the studied fleets and other fleets are impressive given these changes.
Here is another point to remember. Many of these add-on technologies that are found on today’s diesel trucks also can be used on alternative fuel trucks to help extend range. Let’s use battery electric vehicles as an example. A 20% increase in range will allow a battery electric truck with a range of 200 miles to go an additional 40 miles without needing to be charged. That’s a big deal.
As we travel through what we at NACFE have dubbed the “messy middle,” it is important to remember that we can still make strides improving the freight efficiency of diesel-powered trucks at the same time we can migrate the efficiency-enhancing technologies to the new zero- and near-zero emissions trucks to extend range, thereby making them even more efficient.
