Heavy Duty Trucking Logo
MenuMENU
SearchSEARCH

California Won't Enforce Trailer GHG Rules for at Least Two Years

The California Air Resources Board is suspending enforcement of its greenhouse-gas emission standards for trailer for at least two years.

David Cullen
David Cullen[Former] Business/Washington Contributing Editor
Read David's Posts
December 5, 2019
California Won't Enforce Trailer GHG Rules for at Least Two Years

CARB noted that, in the meantime, it will continue to administer the California GHG trailer regulation on a voluntary basis.

Photo: U.S. DOT

2 min to read


The California Air Resources Board is suspending enforcement of its greenhouse-gas emission standards for trailers for at least two years. The Golden State-specific rules were scheduled to go into effect on Jan. 1.

CARB stated in its Dec. 3 announcement that “this suspension of enforcement will, at a minimum, be in effect for model year 2020 and 2021 trailers manufactured before January 1, 2022.” The agency noted that it will provide at least six months’ written notice before it does begin enforcing the GHG trailer standards.

Ad Loading...

The enforcement delay was driven largely by the fact that as of Dec. 3, only one trailer OEM had been certified by the state as meeting the CARB standards, Act Research pointed out in an advisory. Without that certification, trailer makers would have not been authorized to sell within California any trailers manufactured after Jan. 1, 2020.

“Given the lack of certified trailers, trailer sales within California would have been significantly impacted,” stated Act Research. “Once the stock of available trailers produced before 1/1/20 was sold, there would be no new certified units available for sale within the state.”

Along with the lack of progress by trailer builders to meet the deadline, CARB cited as a related factor the legal challenge to the federal trailer GHG rules put up in 2017 by the Truck Trailer Manufacturers Association, which has stalled and prevented federal enforcement of those requirements.

Ad Loading...

Per CARB, the 2020 standards are “intended to make trailers more efficient and lower the greenhouse gas emissions associated with their use.” Affected trailer types include box-type (dry van and refrigerated van trailers of all lengths), flatbed, and tank trailers as well as container chassis. 

The California standards largely align with the stalled federal GHG rules for trailers. CARB has stated that the GHG trailer rules “can be met through aerodynamic improvements, low rolling resistance tires, tire pressure systems (Tire Pressure Monitoring System/Automatic Tire Inflation System), and/or weight reduction.”

CARB noted that, in the meantime, it will continue to administer the California GHG trailer regulation on a voluntary basis, including processing and approving applications to certify 2020 and subsequent model year trailers.

The agency said that effort on its part “will assist both trailer and equipment manufacturers seeking to comply with the trailer requirements in future model years and entities seeking to purchase new 2020 and subsequent model year California-certified trailers. CARB will not, however, enforce the standards for model year 2020 and 2021 trailers manufactured before Jan. 1, 2022.”

More Equipment

Gray Volvo tractor pulling trailer on open highway
Fuel Smartsby Deborah LockridgeMay 1, 2026

New High-Horsepower Natural Gas Engine Could Expand Fleet Options

Westport and Volvo are demonstrating a 500-hp truck with diesel-like efficiency — one that also offers what Westport says is a better pathway to using hydrogen fuel in trucks.

Read More →
Aurora Innovation self-driving truck.
Equipmentby News/Media ReleaseApril 30, 2026

Hirschbach Announces Plan to Deploy 500 Aurora Autonomous Trucks

Hirschbach and Aurora Innovation have inked a non-binding deal outlining a path to deploy 500 Aurora Driver-powered trucks into fleet operations.

Read More →
Bosch-Kodiak self-driving truck partnership.
Equipmentby News/Media ReleaseApril 30, 2026

Bosch, Kodiak AI Advance Toward Scaled Production of Autonomous Truck Hardware

New sensor integrations and component validation signal a shift from strategy to execution as Kodiak and Bosch push toward high-volume driverless truck deployment.

Read More →
Ad Loading...
Great American Trucks: REO
Equipmentby Jack RobertsApril 29, 2026

Great American Trucks: REO

The evolution of the modern truck was a long, slow affair. But perhaps no other company did more to establish the template for what a modern truck should be, and how it should perform, than REO.

Read More →
Western Star's Star Nation customer event.
Equipmentby News/Media ReleaseApril 27, 2026

Western Star Doubles Down on Driver Pride With 2026 Star Nation Experience

Western Star has expanded its operator-focused Star Nation competition and outreach to spotlight skill, attract new drivers, and strengthen industry ties.

Read More →
HDT Spotlight: Volvo VNR test drive.
Equipmentby Jack RobertsApril 23, 2026

Is the All-New VNR Volvo's Safest Truck Ever?

The all-new Volvo VNR is jam-packed with advanced safety features. Join HDT for a first-hand look at how Volvo is keeping drivers safer and productive on the road.

Read More →
Ad Loading...
2026 Volvo VNR
Equipmentby Jack RobertsApril 22, 2026

Volvo Redesigns the VNR With Drivers and Tight Turns in Mind

At Volvo’s New River Valley customer center, the all-new VNR proves that maneuverability, safety, and driver confidence can coexist in a regional-haul workhorse.

Read More →
Great Dane trailer.
Equipmentby News/Media ReleaseApril 21, 2026

FTR: Trailer Orders Jump in March, but Demand Still Lags

March trailer orders posted an unexpected monthly jump, but demand still trails historical norms as fleets prioritize power units over trailing equipment.

Read More →
Humble cabless autonomous freight hauler.
Equipmentby News/Media ReleaseApril 21, 2026

Autonomous Start-Up Humble Announces Cabless Autonomous Electric Hauler

A new autonomous truck startup company is targeting yard, port, and short-haul freight with a lighter, fully autonomous platform designed for dock-to-dock moves.

Read More →
Ad Loading...
Circles with trucks demonstrating sustainable features and Top Green Fleets logo
Fuel Smartsby Deborah LockridgeApril 16, 2026

Top Green Fleets of 2026: Nomination Deadline Extended

Is your company a leader in sustainability efforts among trucking fleets? If so, Heavy Duty Trucking's editors want to hear from you.

Read More →