A D.C. court of appeals ruling exempts trailers from federal greenhouse gas and fuel-­efficiency rules, but California mandates will create the same technology standards for many fleets, while others are adopting the technology because of the economic case for it.

Original equipment manufacturers and engine suppliers have found a variety of ways to meet the challenges posed by the 2021 Phase 2 standards for greenhouse gas emissions and fuel efficiency.

The Truck Trailer Manufacturers Association has asked that an appeals court lift a suspension so the association can move forward with its lawsuit seeking to block a Phase 2 greenhouse gas rule provision that would for the first time regulate trailers.

A trailer makers group is asking a federal appeals court to require that two federal agencies state when they plan to make a final decision on a 2016 Obama-era heavy-truck greenhouse gas rule. Whether revised or kept in place, the rule would regulate trailers for the first time.

The California Air Resources Board on Feb. 8 unanimously approved plans to retain two Obama administration Phase 2 greenhouse gas emissions rule provisions for medium- and heavy-duty trucks that would regulate glider kits and trailer emissions.

A proposal by the U.S. Environmental Protection Agency to repeal a limit on the number of glider kits built annually is shaping up to be a battle pitting independent truckers and those that would reap economic benefits from more gliders against environmentalists, new truck makers and most trucking-related trade organizations.

The EPA has notified the Office of Management and Budget the agency intends to issue a proposed rule repealing the greenhouse gas Phase 2 emissions requirement for glider vehicles, glider engines and glider kits.

A federal appeals court has temporarily halted implementation of a provision in Phase 2 of the heavy trucks greenhouse gas rule of 2016, which would have regulated trailer manufacturers for the first time beginning Jan. 1.

In dueling court filings, Environmental Protection Agency lawyers said they want to postpone the start of a federal appeals court case on the trailer section of the Phase 2 greenhouse gas rule while trailer makers are eager to see the new rule scrapped.

ATLANTA — Presentations by Daimler Trucks North America looked to the future, including the notion of CascadiaE, an all-electric Class 8 the parent company of Freightliner Trucks might one day produce.