Legislation that aims to reduce emissions at commercial ports and freight corridors is topping Senate Democrats’ legislative priorities ahead of the upcoming congressional summer recess.

The Federal Highway Administration has announced a notice of proposed rulemaking for states and municipalities to track and reduce greenhouse gas emissions.

A divided federal appeals court has thrown out portions of the 2016 Phase 2 greenhouse gas emissions rule that would have required heavy- and medium-duty trailers for the first time ever to adopt some combination of fuel-saving technologies.

A wide-ranging coalition of business, science and environmental groups is calling on the Biden administration to within the next 18 months set “multi-pollutant climate and clean air standards” that will eliminate particulate matter, oxides of nitrogen and greenhouse gas emissions from new freight trucks and buses.

WASHINGTON — General Motors, Fiat Chrysler, Toyota and many others in the auto industry are siding with the Trump administration in a lawsuit over whether California has the right to set its own greenhouse gas emissions and fuel-economy standards.

For the first time in 40 years, power plants are no longer the biggest source of U.S. greenhouse gas pollution. That dubious distinction now belongs to the transport sector: cars, trucks, planes, trains and boats.

Whatever federal authorities may or may not do to alter parts of the U.S. Phase 2 regulation of greenhouse gases from trucks, California will keep regulations in place that are at least as tough as the October 2016 final rule, and might even get more strict and encompass aspects of nitrogen oxide emissions.

A notice from the U.S. Environmental Protection Agency to revisit parts of the Phase 2 final rule on greenhouse gas emissions from heavy- and medium-duty trucks isn’t likely to create changes quickly, as the agency has not presented plans for expedited action and environmental groups are vowing to pursue a challenge in a federal appeals court — once the case is no longer being held in abeyance.

In a move to respond to concerns by the trailer and glider industry, the U.S. Environmental Protection Agency announced it plans to “revisit” its Phase 2 provisions on greenhouse gas emissions and fuel efficiency for medium- and heavy-duty engines.

MADRAS, Ore. — Fleet owners should not expect the truck and engine sections of the federal Phase 2 rule on greenhouse gas emissions to change before implementation starts in 2021, said Roger Nielsen, the CEO of Daimler Trucks North America.