By David Morgan
WASHINGTON (Reuters) - U.S. regulators on Friday will propose a 24 percent cut in carbon emissions for heavy-duty trucks by 2027 from expected 2018 emission levels, a source familiar with the matter told Reuters.
An official announcement was expected later on Friday. An environmental group said the reduction would equal 1 billion tons in carbon emissions and could lead to deep cuts in other pollutants linked to health problems.
The standard for heavy trucks and vehicles would be the latest rule by the Obama administration aimed at slashing greenhouse gas emissions from the country's biggest emitting sectors.
Transportation-related greenhouse gases are the second-largest source of emissions after power plants. The U.S. Environmental Protection Agency is expected to finalize sweeping greenhouse gas standards for power plants in August.
(Additional reporting by Valerie Volcovici; Editing by Lisa Von Ahn)
