Columbia subject headings:
Freight and freightage--Europe--Congresses.
Freight and freightage--Government policy--Europe--Congresses.
Harvard subject headings:
Freight and freightage--Europe--Congresses.
Freight and freightage--Government policy--Europe--Congresses.
Transportation and state--Congresses.
Transportation and state--European Economic Community countries--Congresses.
Princeton subject headings:
Highway capacity--Europe.
Railroads--Europe--Traffic.
Traffic flow--Europe.