More on Emissions: Where to Now for Diesels?
EPA Seeks Small-Business Input on Phase 3 GHG Rules for Trucks, Buses
The U.S. Environmental Protection Agency is inviting small businesses to give it feedback on the agency's proposed Phase 3 greenhouse gas emissions rules.

EPA says zero-emissions vehicles will be an important part of its Phase 3 greenhouse gas regulations.
Photo: GNA/ACT Expo
The U.S. Environmental Protection Agency is inviting small businesses to give it feedback on the agency's proposed Phase 3 greenhouse gas emissions rules.
EPA is looking for "Small Entity Representatives" to participate on a Small Business Advocacy Review Panel. This panel will focus on the agency’s development of a rule that proposes to set a new phase of greenhouse gas requirements for heavy-duty engines and trucks that would apply beginning in model year 2030.
EPA first adopted GHG requirements for heavy-duty vehicles in 2011. The Phase 1 rule created a new certification and compliance program based on the computer simulation of vehicle carbon dioxide emissions and fuel efficiency rather than emissions and fuel efficiency testing, set performance-based standards, and adopted interim provisions to address impacts on small businesses. The Phase 1 standards began to apply in model-year 2014 for heavy-duty vehicles.
In 2016, EPA adopted a Phase 2 rule that set more stringent CO2 standards, as well as limits for hydrofluorocarbon, methane, and nitrous oxide (three other greenhouse gases.) The Phase 2 standards began to apply in model-year 2021. The Phase 2 rule also updated the prescribed emission simulation model to account for additional and new fuel-saving technologies and included flexibilities for small businesses that were identified by an SBAR Panel for that rulemaking.
This Phase 3 proposal would revise the GHG emission limits for heavy-duty vehicles while relying on the same basic certification and compliance structure already in place. The Phase 3 proposed rulemaking changes are expected to include more stringent vehicle emission standards to apply beginning in model-year 2030, based on revised projections of GHG-emission-reduction technologies used by engine and vehicle manufacturers, including future technology development. In developing the new standards, EPA will consider what it calls “the important role of zero-emission vehicle (ZEV) technologies to significantly reduce air pollution from the heavy-duty vehicle sector.”
The proposal also would include “limited and targeted flexibilities for small businesses,” thus the desire for small-business input.
The panel will include federal representatives from the Small Business Administration, the White House Office of Management and Budget, and EPA. The panel members ask a selected group of “Small Entity Representatives” to provide advice and recommendations on behalf of their company, government, or organization to inform panel members about the potential impacts of the proposed rule on small businesses.
EPA is looking for self-nominations directly from small businesses that may be subject to the rule requirements. Other representatives, such as trade associations that exclusively or at least primarily represent potentially regulated small entities, may also serve as SERs.
Self-nominations must be received by Aug. 29.
More Fuel Smarts

Lessons Learned About Alternative Fuels: Start Small, Stay Flexible
Practical advice on adopting alternative fuels and ZEVs from HDT's 2026 Top Green Fleets, from renewable diesel and natural gas to electric trucks.
Read More →
Kempower Adds Flex EV Charger to Help Support Transition to Megawatt Charging
The Kempower Mega Satellite Flex has both a CCS and MCS connector, allowing operators to serve both types of heavy-duty vehicles.
Read More →
Hino Adds Electric Class 6/7 Truck
Hino says the Le Series is an important step in the company's efforts to reduce environmental impact and support its customers’ sustainability goals.
Read More →
Can Multi-Speed EV Transmissions Solve Heavy Trucking’s Biggest Electric-Vehicle Problems?
A startup called Sigma Powertrain believes purpose-built multi-speed gearboxes can boost efficiency, reduce battery size and improve gradeability for heavy-duty battery-electric trucks.
Read More →
Hendrickson Debuts Electraax E-Axle for Medium-Duty Trucks
Developed with Driventic, Hendrickson's new integrated e-axle is designed to improve efficiency, reduce weight, and extend range in Class 6-7 EV applications.
Read More →
50 Ways Fleets Can Cut Fuel Costs Now — Without Buying New Trucks
Fuel savings don’t come from one big change. They come from dozens of small ones. Here’s how leading fleets are stacking gains across drivers, routing, maintenance, and more.
Read More →
Top Green Fleets 2026: How Fleets Are Reducing Emissions in the Real World
What works in sustainable trucking today? Heavy Duty Trucking's Top Green Fleets are finding practical ways to cut fuel use, reduce emissions, and keep freight moving.
Read More →
California Launching $1 Billion Electric Truck Rebate Program
CARB says the California Clean Fuel Reward program will begin offering point-of-sale rebates of up to $120,000 for electric commercial trucks starting June 26.
Read More →
Mack Unveils EPA 2027-Compliant MP13 Engine With More Power, Better Fuel Economy
Along with unveiling its EPA 2027-compliant MP13 engine, Mack outlined powertrain changes across its Class 6-8 lineup, including new Cummins-based X10 engines.
Read More →
How Volvo’s New D13 Engine Meets EPA 2027 Emissions Without Sacrificing Power or Fuel Efficiency
Volvo says advances in combustion and aftertreatment helped its new EPA 2027 D13 engine avoid the fuel-economy penalties many once expected from tighter NOx emissions limits.
Read More →
