Columbia subject headings:
Transportation--Energy conservation--United States--Periodicals.
Transportation--Energy consumption--United States--Periodicals.
Harvard subject headings:
Energy conservation--United States--Statistics--Periodicals.
Energy consumption--United States--Statistics--Periodicals.
Transportation--Energy conservation--United States--Statistics--Periodicals.
Transportation--Energy consumption--United States--Statistics--Periodicals.
Transportation--United States--Statistics--Periodicals
Princeton subject headings: