Columbia subject headings:
Highway-railroad grade crossings--United States--Safety measures.
Railroad accidents--United States--Prevention.
Railroad crossings--United States--Safety measures.
United States. Federal Railroad Administration--Rules and practice--Evaluation.
Harvard subject headings:
Highway-railroad grade crossings--United States--Safety measures.
Railroad accidents--United States--Prevention.
Railroad crossings--United States--Safety measures.
United States. Federal Railroad Administration--Rules and practice--Evaluation.
Princeton subject headings:
Highway-railroad grade crossings--United States--Safety measures.
Railroad accidents--United States--Prevention.
Railroad crossings--United States--Safety measures.
United States. Federal Railroad Administration--Rules and practice--Evaluation.