The impact of trucks on greenhouse gas emissions is oversized. Comprising just over 4 percent of vehicles in the United States and 9 percent of total mileage, they consume more than 25 percent of fuel—50 billion gallons of diesel each year. Worldwide, road freight is responsible for about 6 percent of all emissions, and growing.
There are two tracks for increasing fuel efficiency: (1) building it into the design of new trucks and (2) driving it up in rigs already on the road.
New models are sporting:
- better engines and aerodynamics,
- lighter weights,
- less rolling resistance for tires,
- hybridization, and
- automatic engine shutdown.
Based on 2010 U.S. prices, investing in these modernizations for a new truck can cost around $30,000, but save almost that much in fuel costs per year.
Because tractor-trailers remain on the road for many years, addressing the efficiency of existing fleets is critical. An array of measures can trim energy waste and increase fuel performance, such as anti-idling devices, upgrades that improve aerodynamics and reduce rolling resistance, and automatic cruise-control devices. Added up, they can make a significant dent in fuel use and costs.
“The greenest gallon”: Anderson, Ray C. Confessions of a Radical Industrialist. New York: St. Martin’s Press, 2009.
domestic freight tonnage: Davis, Stacy C., Susan W. Diegel, and Robert G. Boundy. Transportation Energy Data Book: Edition 35. Oak Ridge National Laboratory and U.S. Department of Energy, 2016.
United States…[use] of diesel: ATA. “American Trucking Trends.” Arlington: American Trucking Association, 2011.
percent of vehicles…mileage…[and] fuel: The White House. Improving the Fuel Efficiency of American Trucks. Washington, D.C.: The White House, 2014; Davies, Alex. “Making Trucks More Efficient Isn’t Actually Hard to Do.” WIRED. June 24, 2015.
road freight…emissions: Ribeiro, Suzana Kahn, and Shigeki Kobyashi. “Transport and Its Infrastructure.” In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK, and New York: Cambridge University Press, 2007.
[growth] outpacing…personal transportation: Eom, J., L. Schipper, and L. Thompson. “We Keep on Truckin’: Trends in Freight Energy Use and Carbon Emissions in 11 IEA Countries.” Energy Policy 45 (2012): 327–341.
modernizations…cost around $30,000: National Academy of Sciences. “Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles.” Washington, D.C.: National Academies Press, 2010.
Payback…one to two years: Lee, Tessa Margaret, and Matthew Stanley Cullinen, eds. Road Transport: Unlocking Fuel-Saving Technologies in Trucking and Fleets. New York: The Carbon War Room Research and Intelligence Group, 2012.
Tractor-trailers…average [lifespan]: Lee and Cullinen, Road Transport.
reducing fuel use…yearly savings: Lee, Tessa, ed. Confidence Report: Idle-Reduction Solutions. New York: Carbon War Room and North American Council for Freight Efficiency, 2014.
Correction: Diesel trucks were first introduced in the 1930s, hit their stride in the 1950s, and now move roughly half of land freight.
Project Drawdown defines the trucks solution as: the increased use of fuel reduction technologies and approaches for trucking. This solution replaces conventional trucking technologies and approaches.
Heavy trucks use about 50 percent of all freight industry energy, and light trucks another 20 percent; trucks are, therefore, responsible for a majority of emissions in the freight industry. Growth in emissions continues despite the use of more efficient vehicles and despite reduced freight demand from the 2008 financial crisis. Carbon emissions from trucking and other commercial operations are predicted to grow even more rapidly than those from personal transportation.
A number of design and technology measures are readily available to increase a truck’s fuel efficiency, including: low-rolling resistance tires, more efficient engines, devices to reduce idling and aerodynamic drag, and predictive cruise control. These can significantly improve fuel economy, and in many countries such measures have to some degree been implemented. This work examines the potential emissions and financial impact of a high adoption of a package of these technologies instead of continued use of conventional trucks.
Total Addressable Market 
The total addressable market for trucks is defined as the total trucking freight demand to 2050. This analysis compares the rapid adoption of efficient trucking technology to the use of conventional trucks globally. An "efficient truck" is defined as one with a package of efficiency technologies  providing around 40 percent efficiency improvement compared to 2008 vehicles. Current adoption  of these technologies in the trucking industry is estimated at 2 percent globally, driven in part by fuel efficiency and emissions standards for cleaner trucking in some countries.
Adoption Scenarios 
Impacts of increased adoption of trucks from 2020-2050 were generated based on three growth scenarios, which were assessed in comparison to a Reference Scenario where the solution’s market share was fixed at the current levels.
- Plausible Scenario: Based on an estimated 50 percent share of the market by 2050, a linear annual growth was used to determine adoption from the base year (Ogburn and Ramroth, 2007).
- Drawdown Scenario: Using estimates of when truck fuel efficiency legislation may become mandatory for 16 regions identified by the International Council on Clean Transportation (ICCT, 2012), it is assumed that all new trucks sold thereafter are 40 percent efficient.
- Optimum Scenario: Based on an estimated 100 percent share of the market by 2050, a linear annual growth was used to determine adoption from the base year (IEA, 2012).
Emissions only included fuel emissions, with diesel emissions factors calculated from the Intergovernmental Panel on Climate Change (IPCC) guidelines.
The cost of upgrading to an efficient truck is estimated at US$50,000  in addition to the cost of the vehicle.  Operating costs were inclusive only of fuel costs for the conventional truck, derived from 8 sources including the IEA and ICCT.
The Plausible Scenario results in emissions reductions of 6.2 gigatons of carbon dioxide-equivalent greenhouse gases at a cost of US$543 billion, and a net operations cost savings of US$2.8 trillion for the period 2020-2050. The Drawdown Scenario results in 11.4 gigatons of emissions, compared to 10.2 gigatons reduced in the Optimum Scenario.
Our results show that the long-haul heavy-truck industry could expect to see a considerable return on investment through the adoption of typical fuel efficiency technologies. The relatively short payback periods of many fuel efficiency measures, combined with most trucks being commercially deployed on the road for well over a decade, ensure that fuel efficiency provides greenhouse gas reductions and cost savings for the party paying for fuel. In addition, fuel efficiency helps reduce toxic ambient air pollutions such as sulfur oxide, nitrous oxide and particulate matter, which contribute to poor air quality in many urbanized areas. For these and other reasons, we expect that adoption could be very high for these technologies. Although the global road freight sector is diverse, with variations in regulations, fuel costs, road quality, and truck models from region to region, solutions may be customized by country and truck operator.
Adoption of this solution does, however, have a few barriers:
- Fragmented markets and limited access to capital: In many countries, the trucking industry has a large number of owner-operators (each with fewer than five trucks), and multiple stakeholders involved in trucking transactions. This could reduce the ratio of benefits to costs if borrowing/investment costs are higher due to the small size of the operation.
- Split benefits: With many truck-trailer combinations, the trailer has a different owner than the truck, creating a question of who pays for the upgrades and who reaps the benefits of fuel savings.
- Lack of information, education, trust, and momentum in many countries.
The adoption of such fuel-saving clean technologies for commercial truck fleets offers clear potential to achieve significant reductions in global greenhouse gas emissions, while generating considerable operational lifecycle cost savings for the road freight sector. However, there is a critical need for policy guidance to help small operators realize the financial benefits of long-term investment in these technologies.
 For more on the Total Addressable Market for the Transport Sector, click the Sector Summary: Transport link below.
 The package of efficiency technologies was identified as a typical set, including: aerodynamics improvements, transmissions upgrades, low-resistance tires, light-weighting, management systems, and ICT systems.
 Current adoption is defined as the amount of functional demand supplied by the solution in the base year of study. This study uses 2014 as the base year due to the availability of global adoption data for all Project Drawdown solutions evaluated.
 For more on Project Drawdown’s three growth scenarios, click the Scenarios link below. For information on Transport Sector-specific scenarios, click the Sector Summary: Transport link.
 All monetary values are presented in US2014$.
 Derived from 5 sources, including the US National Academy of Science, the Carbon War Room, and the UN Centre for Regional Development.