EPA announces plans to reduce pollution from heavy-duty trucks EPA announced Tuesday it will start the process of writing a new rule.

The Environmental Protection Agency announced Tuesday that it plans to set new rules about pollution from heavy-duty trucks, which release more than 20 percent of pollution from transportation that contributes to smog.

The "cleaner trucks initiative" aims to reduce emissions of nitrogen oxides, a group of gases that contribute to global warming and form smog. The EPA doesn't have a specific goal for the reduction, but officials said they will be looking at new technologies that could reduce and more accurately test emissions from trucks.

EPA sets different regulations for different kinds of vehicles. Heavy-duty trucks include semi trucks and other large pickup trucks, buses and recreational vehicles, according to the EPA definition.

Acting EPA Administrator Andrew Wheeler told reporters the move will especially help cities and areas with heavy stop-and-go traffic to meet requirements to reduce ozone and other pollutants.

The agency could take a page from California for this rule. The state has been implementing new requirements for heavy-duty trucks and buses to be replaced with updated engines and technology to reduce pollution by 2023.

The head of EPA's air office Bill Wehrum said Monday night the agency will be working with California on the new rule, though they might not agree with all of California's approach.

While the agency is working on new rules for larger trucks, Wehrum said they consider this effort completely separate from efforts to reduce fuel-efficiency standards for smaller cars and trucks, which is at odds with California's higher standards.

The EPA will begin the process of writing a proposed rule, according to the announcement Tuesday. It would still need to be made available for public comment before anything is final.