State and local policies to regulate the use of plastic bags have significantly reduced how many of them are found littered along U.S. shorelines — potentially cutting that type of waste in half in certain places, a new study published Thursday in the journal Science found.

Researchers find that nationwide policies to ban plastic bags may be paying off, with fewer showing up during coastal cleanups.

A new study from the University of Delaware and Columbia University looked at plastic bag bans and fees in jurisdictions across the United States to gauge their effectiveness. The researchers found that plastic bag policies led to a 25% to 47% decrease in plastic bags as a share of total items collected in shoreline cleanups relative to areas without policies.