One participant suggested the European Community should construct huge parking lots at borders across Western Europe. Another recommended buying shares in a car rental company.
Last week Community environment ministers agreed to the ''obligatory introduction'' of lead-free gasoline in the 10 EC countries beginning in 1989.
But they did not specify how much. West Germany has pledged to introduce lead-free gasoline - perhaps even phasing out leaded fuel - much sooner than 1989. Problems are likely to arise when Germans want to leave Germany.
''To comply with the new EC directive, the Greek government, for example, could decide to designate one pump and only one pump to handle the country's tiny supply of lead-free gasoline,'' quipped a participant at the meeting. ''The line of Mercedes and Volkswagens at that pump in the summer would stretch back to Germany.''
EC officials say the potential problem of one or more European countries moving faster than the others to get the lead out of gasoline will be resolved over time. Others wonder.
''We've all got to move in one direction together,'' said an EC expert. ''Otherwise, there will be chaos.''
Another suggested the Germans begin forming that line at that one Greek pump tomorrow.