Columbia subject headings:
Highway engineering--United States--Databases.
Roads--United States--Databases.
Transportation, Automotive--United States--Databases.
Harvard subject headings:
Highway engineering--United States--Databases.
Roads--United States--Databases.
Transportation, Automotive--United States--Databases.
Princeton subject headings:
Databases.
Highway engineering--United States--Databases.
Roads--United States--Databases.
Transportation, Automotive--United States--Databases.