Section 4(f) consists of a federal law intended to prevent conversion of certain parks, wildlife, and waterfowl refuges, recreation areas, or historic properties to transportation use, unless the U.S. Department of Transportation determines there is no feasible or prudent alternative, and all possible planning has been done to minimize harm of such properties.
Section 4(f) study is underway to identify such properties and coordinate with associated governmental and non-governmental bodies to explore permitting and assessing project impacts at such properties, and explore ways to avoid, minimize, and mitigate for the impacts.