Trucks and Buses

More efforts needed
Shutterstock 599847713

In this report

Emissions from trucks and buses have risen by around 2.6% annually since 2000. While policy coverage for heavy-duty vehicles (HDVs) still lags behind that for cars and vans, momentum has been growing. With new policies adopted in India in 2018, and with benchmarking for the EU HDV CO2 standards beginning in July 2019, an estimated 70% of HDVs sold worldwide in 2019 were in markets that had fuel economy and CO2 emissions standards in place, compared with less than 50% in 2016. To achieve the SDS, more countries must adopt standards – and existing ones must become more comprehensive and stringent. Green freight programmes, which track and promote efficient truck operations and technologies, can help fleets and owners/operators spread best practices and share information. In urban settings, rapid electrification (especially of buses, but increasingly also of medium- and heavy-duty trucks) will help.

CO2 emissions from heavy-duty vehicles in the Sustainable Development Scenario, 2000-2030

Tracking progress

Since 2000, HDV energy consumption and tailpipe CO2 emissions have increased by 2.6% per year, with trucks responsible for more than 80% of this growth. Rising emissions and energy use are driven primarily by greater economic activity and increased demand for goods, which translates into more delivery and more trucking activity.

In the near term, vehicle efficiency standards, together with co‑ordinated efforts to improve logistics and operational efficiency, are needed to dampen this growth. In the longer term, switching to low-carbon alternative fuels and powertrains will be needed to decouple rising activity and energy use from CO2 emissions.

After being a decade behind light-duty vehicle (LDV) standards for many years, policy coverage for HDVs has finally begun to catch up. While roughly 85% of cars and light commercial vehicles sold in 2019 were covered by fuel economy standards, 70% of HDVs sold globally were also operating in markets with vehicle efficiency regulations. In 2016, however, coverage had already reached nearly 85% of LDVs but only 50% of HDVs.

Heavy-duty vehicle sales in countries with adopted fuel economy (and/or GHG/CO2) standards, 2005-2019


Light-duty vehicle sales in countries with adopted fuel economy (and/or GHG/CO2) standards, 2005-2019


Substantial progress has been made recently in establishing vehicle efficiency and CO2 emissions standards for HDVs:

  • India put new HDV fuel economy standards in place in April 2018, raising policy coverage of new bus and truck sales to more than half of global sales overall.
  • In January 2019, trucks in the four classes that account for the majority of HDV emissions and fuel consumption, having a gross vehicle weight (GVW) of more than 7.5 tonnes and produced for sale in the European Union, became subject to mandatory monitoring and reporting of fuel consumption and CO2 emissions using the Vehicle Energy consumption Calculation TOol (VECTO). In June 2019, the Official Journal of the European Union published a regulation mandating average specific CO2 emissions reductions (measured in gCO2/tkm) of 15% by 2025 and 30% by 2030 (compared with the July 2019-June 2020 reference period) for regulated classes of new trucks. This baseline for HDV CO2 emissions standards in the European Union raised coverage of all HDVs sold globally to an estimated 55% in 2019. The 2030 target is binding but subject to review in 2022.
  • China’s Phase III standards, which took effect in July 2019, have begun to raise the efficiency of new buses and trucks sold in the world’s largest HDV market.
  • Japan updated its fuel efficiency standards for trucks and buses in March 2019. Setting 2025 as the target year and 2015 as the base year, the standards mandate efficiency improvements of 13.4% for trucks and 14.3% for buses.
  • Argentina, BrazilMexico and South Korea are in various stages of developing policies to improve the efficiency of their HDV fleets. South Korea aims to have new HDV standards in place by 2022.

Since the US EPA introduced its flagship SmartWay programme in 2004, more than 30 countries have established green freight programmes or have joined regional or global ones.

Fuel economy regulations and green freight programmes complement each other well, with the former setting minimum thresholds for vehicle efficiency performance and the latter promoting technical and operational efficiency as well as efficient technologies and best practices.

  • In 2017, Chile became the latest country to establish a national green freight programme, the Giro Limpio.
  • Argentina has set up a road freight efficiency pilot programme (Programa Transporte Inteligente) and is in the initial phases of putting together its own green freight programme.

While cars have shifted away from diesel since the Volkswagen emissions scandal, it is still the primary fuel for HDVs. In fact, the share of diesel in overall oil-based road fuel consumption rose from 38% in 2000 to nearly 45% in 2019, largely due to greater road freight activity.

Although some fuel switching has occurred, the impact on GHG emissions is ambiguous and likely insufficient to achieve the goals of the Sustainable Development Scenario. For instance, the number of natural gas vehicles registered in Europe rose by more than 70% (to more than 6 000 vehicles) in 2019, but the implications for GHG emissions are mixed at best. When potential emissions leakages and maximum efficiency potential are considered together, well-to-wheel emissions reductions range from less than 15% at most to no net benefit whatsoever – or even worse performance than diesel when engine performance is considered – and can even produce near-term climate damage when the higher short-term radiative forcing of natural gas is taken into account.

Fortunately, recent success in electrifying light commercial vehicles and urban buses will provide a foundation for the building up charging infrastructure and garnering the policy support necessary to extend the commercialisation of zero-emission vehicles to heavy-duty trucks and long-distance operations. In the medium and longer term, heavy-duty trucks with regional and long-haul missions, which account for three-quarters of HDV fuel consumption, as well as intercity buses (coaches), will need to transition to low-carbon alternative fuels and powertrains. Options include electrification via battery, plug-in and hydrogen fuel-cell electric vehicles, advanced biofuels and synthetic fuels. 

Urban buses are one of the great success stories of rapid EV market uptake. A market for electric buses emerged quickly owing to depot availability for charging, buses’ frequent stops, municipalities’ ambitions to reduce local air pollution, and the longer-term investment portfolios of (certain) municipal fleet managers.

China has led the way in bringing domestically made batteries and buses to market, first to Chinese cities (Shenzhen became the global model when it transitioned entirely to electric city buses within only a few years) and increasingly to European and Latin and North American ones.

Commercial trucks operating in urban environments, especially those belonging to large co‑ordinated fleets and logistics services, have also begun to electrify rapidly. China again leads the way: the country accounts for 65% of the global fleet of electric light commercial vehicles, with nearly 250 000 on its roads. Many major postal and package delivery companies, among them Amazon, DHLDB Schenker, FedEx, the Ingka Group (which owns Ikea), UPS and the Swiss and Austrian postal services, have pledged to expand their electric fleets through retrofits or outright purchases in the near future.

China has further introduced fleets of hydrogen fuel-cell electric trucks (about 1 800 light commercial vehicles) and buses (about 4 300), most of which operate on fixed routes and refuel centrally at a single station. South Korea and Japan also have ambitious plans to use hydrogen fuel-cell technology in the heavy-duty subsector.

The long-term payback of initial capital investments, together with the need to address broad sustainability issues such as tailpipe pollutant and CO2 emissions, may incite these fleets to electrify even more quickly than privately owned cars. City-level efforts to contain air pollution, including targets for phasing out diesel and internal combustion engines, combined with corporate efforts to anticipate and take the lead on pressing public issues, will further spur EV adoption for light-duty commercial fleets.

Building upon recent momentum, the rapid adoption of battery electric buses and trucks in cities will not only reduce energy consumption but cut local pollutant and CO2 emissions. A growing number of zero-tailpipe-emissions medium- and heavy-duty truck models are becoming commercially available (see section on zero-emission trucks below).

Electrification of these modes began in China, where annual sales exceeded 1 000 for the first time in 2017, and where more than 6 000 battery electric trucks, mostly for garbage collection and other municipal operations, were sold in 2019. Although cumulative sales of more than 12 000 electric trucks in the past decade account for only slightly more than 0.1% of heavy-duty trucks on China’s roads, it currently leads the electrification of heavy-duty road freight.

In the United States, 15 states and the District of Colombia have in July 2020 taken steps to replicate the success of California’s ZEV mandates in accelerating electrification and other zero-emission technologies in light-duty vehicles for heavy-duty trucks. Spurred by the passage of California’s Advanced Clean Trucks rule, which requires OEMs producing trucks for the California market to sell increasing shares of ZEV trucks in each segment starting in 2024, these states have signed a joint memorandum of understanding aiming to boost the ZEV truck market.

In Europe, the number of battery and plug-in electric trucks registered more than doubled year-on-year in 2019, with nearly 750 new vehicles registered, 80% of them in Germany. Europe is also on the threshold of selling 1 000 electric heavy-duty trucks in one single year.

Meanwhile, momentum continues to build in the demonstration and commercialisation of zero-emission trucks – the majority of which are also battery electric. With greater battery capacity, the GVW and range thresholds for EVs continue to rise. In going beyond demonstrating small fleets of zero-emission HDVs to commercially operate thousands of units, China has emerged as the first mover in the electrification of heavy-duty transport.

The range of prototypes, demonstration trucks, and commercially available hydrogen fuel-cell and plug-in electric vehicles continues to expand. Bollinger and Toyota in North America, Tata in India, and BYD and Chanje in China have introduced prominent new 2019 and 2020 models. In October 2019, Daimler Trucks – the world’s largest truck maker – committed to sell only zero-emission vehicles by 2039 and to abandon the development of natural-gas-powered trucks. The CEOs of Volvo and Scania also recently expressed their views that the electrification of HDVs is viable – and crucial – to reach climate targets. Both Volvo Trucks and Renault Trucks started producing electric trucks in 2019, and Scania deployed two battery electric city distribution trucks of 27‑tonne GVW in early 2020.

To complement the Drive to Zero campaign spearheaded by Calstart, the Zero-Emission Technology Inventory (ZETI) provides governments and fleets with up-to-date information on the rapidly expanding medium- and heavy-duty ZEV models being offered. ZETI provides a zero-emission-technology inventory through an interactive online data and resource clearinghouse that lists commercially available medium- and heavy-duty truck and bus models; it can be searched by region, manufacturer and vehicle type.

This figure provides an overview of selected electric trucks which have been introduces to the market recently or will be available for sale in the near future. This list is not exhaustive and focuses on freight vehicles with a long range, which excludes terminal vehicles and service vehicles for street cleaning or refuse collection.

While the scope of energy efficiency and emissions regulations is being expanded, it will be increasingly important to accelerate the uptake of low-carbon alternative powertrains and fuels.

As HDV efficiency standards will need to be introduced in places where they do not yet exist, a G20 clean-transport task group is helping countries begin to benchmark current technologies, categorise truck and bus operations, and use models such as VECTO and the Greenhouse Gas Emissions Model (GEM) to obtain the information necessary to design regulations.

Meanwhile, countries that already have standards in place will need to make them more stringent to cut emissions further; China in particular would benefit from stronger Phase IV standards.

Decoupling energy use from CO2 emissions will require a shift from fossil fuels to true low-carbon alternatives. Biofuels can serve as a bridge between internal combustion engines and zero-emission powertrains relying on hydrogen and/or electricity. But policies that focus only on stimulating biofuel production without taking into consideration real-world emissions impacts, such as blending mandates and production quotas, are likely to promote the lowest-cost production pathways. This  could lead to only marginal reductions or even, in some cases, net increases in well-to-wheel emissions relative to fossil diesel or natural gas.

For these reasons, policies should explicitly incentivise alternative fuels based primarily on their well-to-wheel performance, as low-carbon fuel standard frameworks do. They should also consider the sustainability and natural resource impacts of biofuel production, as is the case with the EU Fuel Quality Directive.

Electric and fuel-cell electric trucks and their supporting infrastructure are at the very early stages of deployment, with many vehicles still being introduced in city-level pilots. Their adoption will be more dependent on policy support than other modes because their purchase price is higher and they depend more on fast or dynamic charging than LDVs. Indeed, in cities and countries where zero-emission heavy-duty truck models have already been deployed, adoption has been spurred by either policy incentives or corporate initiatives – most widely by a combination of the two.

Policies also need to stimulate the adoption of technologies to support zero-emission vehicles. Although policies to promote electric trucks will be able to build on LDV deployment success, they will need to expand beyond them to focus on infrastructure. For instance, purchase subsidies and/or favourable loan terms for fleets looking to purchase heavy-duty trucks and their requisite infrastructure could help spur their deployment.

Just as with LDVs, regulations that set minimum HDV performance standards, such as for fuel economy or CO2/GHG emissions, as well as pollutant emissions standards, attract innovation and investment for the manufacturing and selling of cleaner trucks. Further, fiscal policies such as road tolls and fuel taxes that make up for the road infrastructure impacts of heavy-duty trucks and the various externalities of fuel consumption (e.g. pollutant emissions, energy security risks) incorporate some of the true costs of incumbent polluting ICE technologies.

As part of their Drive to Zero campaign, CALSTART outlines and provides examples of these and other policies, including financial incentives (e.g. purchase incentives, direct subsidies, congestion pricing and zero- and low-emission zones) and incentives to spur the deployment of rapid-charging infrastructure, as well as policies suited to municipal and corporate fleets, such as exclusion zones and procurement requirements.

In late 2019, California and seven other US states committed to accelerate the adoption of zero-emission medium- and heavy-duty vehicles through a ZEV programme that has sales and reporting requirements. California aims to adopt the programme in 2020, and some of the other participating states are already promoting zero-emission buses and trucks by both introducing electric transit buses directly and by using VW settlement funds for medium- and heavy-duty electrification. In passing Senate Bill 5811 (2020) in March 2020, Washington became the twelfth US state to adopt California’s ZEV mandates, and the first to expand them beyond LDVs to include medium-duty vehicles.

In April 2020, the California Air Resources Board (CARB) released the final draft of the Advanced Clean Trucks Standard, a proposal that will require all truck manufacturers selling more than 500 trucks annually in the state to produce electric trucks. Under the policy, a certain percentage of these manufacturers’ sales in California must be electric trucks. CARB will vote on the proposal in late June.

EU regulators considered using either super credits or a zero- and low-emission vehicle (ZLEV) mandate, both of which would ultimately reward manufacturers of zero- and low-emission trucks and buses by relaxing HDV CO2 emissions standards. They ultimately adopted a super-credit system through 2024, and a benchmark that relaxes fuel economy standards for manufacturers achieving a 2% market share of ZLEVs after 2025, but it is capped at 3%.

While such schemes promote the market adoption of electric and hydrogen trucks in principle, if they are not designed to consider the variability within heavy-duty vehicle segments, they may actually compromise the efficacy of emissions standards. It is crucial that standards take into account the unevenness of electrification potential (in the absence of policies) and of differing emissions implications from one segment to another.

For instance, electrification of urban buses and municipal fleets will probably be rapid, so since most emissions come from regional and long-haul trucking, providing too many credits to manufacturers of electric urban buses and municipal trucks is likely to arbitrarily reward certain manufactures while diluting the effect of the standards.

Finally, regulations will need to extend beyond trucks to the trailers they pull. Canadian and US second-phase GHG emissions standards are the first in the world to regulate trailer emissions, and although the United States has temporarily suspended this component of its legislation, the US EPA and NHTSA are defending their statutory authorities to set trailer standards. Meanwhile, Canada’s extension of the new standards to include trailers has gone forward, and DG CLIMA is investigating options for applying CO2 standards to truck bodies and trailers.


The authors are grateful to Felipe Rodriguez, ICCT, for reviewing and providing valuable feedback on a draft of this section.