Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

Stricter Truck Emissions Standards are a Gorilla of a Monkey Wrench [Commentary]

CARB may be able to quickly squeeze heavy-truck emission limits yet tighter, explores HDT's Contributing Washington/Business Editor David Cullen in the Passing Zone column.

David Cullen
David Cullen[Former] Business/Washington Contributing Editor
Read David's Posts
March 27, 2023
Stricter Truck Emissions Standards are a Gorilla of a Monkey Wrench [Commentary]

CARB may be able to quickly squeeze heavy-truck emission limits yet tighter, explores HDT's Contributing Washington/Business Editor David Cullen in the Passing Zone column.

Graphic: HDT

3 min to read


If approved, a request by California to enact markedly stricter heavy-truck emissions standards than those set by the federal government will massively disrupt the already-fraught view trucking holds of the upcoming rules laid out by the Environmental Protection Agency.

Ad Loading...

This gorilla of a monkey wrench will vigorously shake the tightrope of a timeline that truck and engine manufacturers are navigating to ensure compliance with the new regulations while delivering the performance expected by fleets.

Disrupting the engineering already in motion by changing the rules this late in the game would ripple down the manufacturing supply chain to gum up the works. That would upset fleet plans to replace old trucks with new in the face of another pre-buy explosion.

Ad Loading...

It’s not a done deal, but news reports in the general media earlier this month strongly suggested that approval was imminent. Washington Post reporter Anna Phillips is credited with having broken the news on March 20. EPA “intends to grant California ‘waivers’ to enforce environmental rules that are significantly tougher than federal requirements and that state regulators have already approved,” she reported.

But wait, there’s more bad news. Whenever California secures waivers of preemption, per the California Air Resources Board, the federal Clean Air Act “allows other states that are or have been noncompliant with federal ambient air quality standards to adopt California’s standards as their own.”

To date, 13 states and the District of Columbia have adopted all or part of certain California emission standards.

Within three days of the Post story, the American Trucking Associations issued a blistering press release on the waiver request. ATA keyed in on how changing upcoming emissions rules now could derail the supply chain that drives truck production.

“Our industry hopes these reports aren’t true,” stated ATA President and CEO Chris Spear. “The state and federal regulators collaborating on this unrealistic patchwork of regulations have no grasp on the real costs of designing, building, manufacturing, and operating the trucks… As we learned in the pandemic, the supply chain can be a fragile thing — and its integrity must be preserved at the national level.”

Ad Loading...

One day after ATA spoke out, word came that a new advocacy group of trucking stakeholders had been formed to “get to zero emissions in a responsible and feasible manner.” The Clean Freight Coalition consists of motor carriers, truck makers, and truck dealers. Its founding members include ATA, the Truckload Carriers Association, and the Truck & Engine Manufacturers Association (EMA).

The Clean Freight Coalition has twin interrelated goals: Advocate for public policies that transition toward a zero-emission future while assuring “affordable and reliable freight transportation and [protecting] the nation's supply chain.”

Perhaps the launch of CFC stemmed from last summer’s decision by EMA to withdraw its lawsuit against CARB that contended the agency did not provide enough lead time for truck and engine makers to meet its 2024 emission standards.

That EMA legal action had spurred substantial blowback by environmental groups and some of its own members, including Cummins, Ford, and GM, that publicly stated they did not support the litigation. For example, a joint letter sent by 34 regional and national environmental groups upbraided EMA’s member leadership, including the heads of Daimler Truck NA, Navistar, Paccar, and Volvo Group NA, for “harmful EMA lobbying and disinformation campaigns designed to slow or stall the transition to cleaner trucks.”

So, it would seem that the further development of engines and trucks to comply with 2024 and 2027 diesel emission standards is not likely to go as anyone has hoped. At this point, whether it will be a race back to the drawing boards or a steady push to the current finish line is anyone’s bet.

Ad Loading...

This commentary appears in the April 2023 issue of Heavy Duty Trucking.

More from David Cullen's Passing Zone column: M&A in Trucking: A Tale of Two Year

Subscribe to Our Newsletter

More Fuel Smarts

Illustration showing DEF tank and Detroit engine
Equipmentby Deborah LockridgeJune 18, 2026

DTNA Software Update Gives Truckers More Time Before DEF Derates Take Effect

The changes reflect EPA guidance aimed at reducing downtime caused by emissions-system faults while maintaining compliance requirements.

Read More →
Illustration of exhaust aftertreatment system on an AI-inspired blue background and a green fuel pump nozzle in the foreground.
Maintenanceby Deborah LockridgeJune 15, 2026

New Agentic Predictive Maintenance Report Demonstrates How Degraded Aftertreatment Systems Waste Fuel

Questar analyzed a large mixed-class fleet and discovered it was wasting as much as $30 in fuel per vehicle, per day, because of mechanically degraded aftertreatment systems.

Read More →
Amazon electric cargo bike on New York City street
Fleet ManagementJune 15, 2026

New York City's Microhub Project is Delivering Results

Trucking, last-mile delivery companies, and environmental advocates like what they are seeing so far with New York's microhub program.

Read More →
Ad Loading...
Red Kenworth truck pulling Paper Transport trailer
Fuel Smartsby Deborah LockridgeJune 2, 2026

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 →
Composite image of different angles of the Kempower charger
Fuel Smartsby News/Media ReleaseMay 29, 2026

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 →
White Hino Le electric tractor on show floor
Equipmentby News/Media ReleaseMay 26, 2026

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 →
Ad Loading...
Sigma Powertrain BEV transmission.
Fuel Smartsby Jack RobertsMay 26, 2026

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 →
Red Hendrickson e-axle at ACT Expo booth
Equipmentby News/Media ReleaseMay 22, 2026

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 →
Fueling trucks.
Fuel SmartsCover Storyby Deborah LockridgeMay 18, 2026

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 →
Ad Loading...
Collage of HDT Top Green Fleets with logo
Fuel Smartsby Deborah LockridgeMay 18, 2026

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 →