Diesel trucks have always been on the hot seat when it comes to environmental issues. This is because heavy-duty vehicles have a carbon footprint of 223 tons of carbon dioxide, and are thus subject to increasingly stringent emissions standards. In this article, we will review the EPA heavy-duty truck emission regulations and how they affect fleets and fleet managers.

Why are Diesel Truck Emissions Regulated?

When left unmonitored, diesel truck emissions can pose a significant threat to public health by compromising air quality. Diesel truck emissions contain particulate matter (PM), nitrogen oxides (NOx), and greenhouse gases (GHGs). NOx forms ground-level ozone, while GHGs contribute to climate change, and PM causes respiratory problems and health issues.

The U.S. Environmental Protection Agency (EPA) is the assigned regulatory agency for overseeing heavy-duty truck emissions in the States. The EPA has implemented more stringent standards over the years in response to climate change hazards to reduce the impact of diesel truck emissions on the environment and on human health.

State-specific emissions programs, such as that of the California Air Resources Board (CARB), may set even more specific and stricter measures. Under the California Emissions Program, for instance, CARB has further reduced allowable NOx emissions to about 0.02 grams per brake horsepower-hour (g/bhp-h), down from the previous standard of 0.5 g/bhp-h.

What are the Current EPA Regulations for Heavy-Duty Trucks?

The EPA’s regulations apply to commercial trucks and buses, as well as on-highway and non-highway diesel engines. They cover a wide range of pollutants including GHGs, PM, and NOx. The regulations currently include the following:

• Clean Trucks Plan
• Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles
• Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards

All heavy-duty trucks are required to comply with these regulations. Non-adherence comes with strict penalties not only for manufacturers but also for fleet operators. In response to these regulations, heavy-duty vehicle manufacturers have incorporated emission control technologies, including diesel particulate filters (DPFs), selective catalytic reduction (SCR) systems, and exhaust gas recirculation (EGR).

Announced in 2021, the Clean Trucks Plan was formed to reduce greenhouse gas emissions and harmful pollutants from heavy-duty trucks. Subsequent rulemakings were published as a result of these, including the Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards, fully outlining the Clean Trucks Plan.

The regulations focus on reducing diesel truck emissions by implementing stringent standards for new vehicles alongside the push to adopt cleaner technologies. Stricter emissions for model year 2027 and beyond are at the core of developments under the Clean Trucks Plan. The aim is to reduce NOx and PM emissions significantly to improve air quality and public health.

Beyond traditional pollutants, the EPA is also tackling greenhouse gas emissions from diesel trucks. The Phase 3 Greenhouse Gas Emissions Standards are designed to make significant reductions in these emissions. This initiative supports the national goal of combating climate change and moving towards a low-carbon economy.

To effectively implement the Phase 3 standards, a mix of technological innovations and operational adjustments will be necessary. Truck manufacturers will need to create and implement more fuel-efficient engines and vehicles. Meanwhile, fleet operators can help by optimizing routes, minimizing idle time, and utilizing advanced telematics systems, which can ultimately reduce fleet fuel costs.

Challenges for the Trucking Industry

Despite the well-meaning efforts of regulatory bodies like the EPA and CARB, there is no denying that these rules pose significant challenges for the trucking industry. There is a need to invent, adopt, and implement new technologies, all of which require a huge amount of resources.

Fleet operators and drivers are important cogs in the industry, and there has to be a shift in strategy in order to keep trucking businesses alive while adhering to environmental standards.

Observing proper vehicle maintenance is crucial in ensuring optimal engine performance, fuel efficiency, and reduced emissions. Additionally, adopting new practices like last mile delivery route optimization may help to reduce fuel consumption by bringing down the distance traveled and minimizing idle time.

Again, adhering to these rules is neither cheap nor easy. At the very least, operators need to shop software to optimize operations, educate drivers about fuel efficiency and new technologies, and upgrade equipment to newer, cleaner options.

However, it’s a challenge that manufacturers and fleet operators need to rise up to, especially since the bigger-picture cost entails environmental degradation and threats to human health. At the end of the day, it’s a collective effort to do our part in the struggle and make everyone’s load a little lighter.