It’s only the beginning of 2026, but 2027 is already on the minds of most in the commercial delivery fleet industry. That’s when the Environmental Protection Agency’s (EPA) stricter nitrogen-oxide (Nox) limits go into effect, with any model year 2027 vehicle being required to meet them.

However, with the administration change that happened a year ago in Washington, questions reside over whether the EPA would move forward with the new standards. In March 2025, the EPA announced its intentions to re-evaluate the 2027 rules put in place under the Biden Administration. In November, however, the agency indicated that it plans to move forward with the 2027 implementation, sticking with the previously announced 0.035 gram/horsepower-hour standard.

The American Truck Associations (ATA), along with its federation of 49 state trucking associations, the Truck Carriers Association, and the National Tank Truck Carriers, have expressed concern with the timeline, unsuccessfully urging EPA Administrator Lee Zeldin in an August 2025 letter to delay implementation until 2031.

Still, engine producers have been making strides with offerings that offer a bridge to the 2027 rules.

Leading engine manufacturer Cummins has made significant waves with its X15 engine line, part of its HELM series of engine platforms, which enables fleet customers to choose the fuel type that best suits their needs.

For its Fifth Generation Freightliner Cascadia, Daimler Truck North America is helping pioneer a 15-liter natural gas engine in the form of the Cummins X15N.

Also part of the Cummins HELM platform is the X15H, a hydrogen-fueled offering. The company says it is continuing research testing of hydrogen engines around the world.
 For medium-duty applications, Cummins introduced the B7.2 diesel, the next engine in its B-series HELM platform, following its B6.7 Octane Engine. The engine is designed to improve unrestricted top-end performance ratings, providing 240 to 340 horsepower and 1,000 pound-feet of torque.

In other Cummins news, the company released a white paper titled “Fuel Economy and CO2 Improvement Potential of Conventional ICE Powertrains,” detailing fuel economy innovations that can be implemented in the short term to boost the efficiency of internal combustion engines for delivery fleets. The white paper aligns with Cummins’s portfolio-wide approach to emissions reductions, as part of its overall Destination Zero strategy.

Even as electric vehicles gain traction and continue to be integrated in delivery fleets worldwide, internal combustion engines will continue to dominate for many years.

As we’re on the topic of lowering emissions, Volvo Trucks North America announced last spring that it would apply for certification of a CARB-24 Omnibus-compliant engine that will meet the California Air Resources Board’s (CARB) emissions standards that it established in 2024. The engine, Volvo says, reduces particulate matter emissions. It also will feature a shorter seven-wave piston for improved combustion, a longer connecting rod that’s designed to reduce friction, a precision needle control valve to optimize fuel flow, and a variable displacement pump to keep parasitic loss to a minimum. It’ll be built on the new Volvo D13 Variable Geometry Turbo (VGT) engine platform, which the company launched in 2025. Once certified, fleets will be able to order the CARB-24 Omnibus-compliant engine in new Volvo VNL and VNR models, with expected available configurations of 425 horsepower/1,450 pound feet of torque or 455 horsepower/1,850 pound feet of torque.

Because 2027 is only a year away, it’s likely that many of the top OEMs will be making significant emissions-reductions-related announcements at most of the major trucking trade events, beginning this spring. So, stay tuned.