From #openttdcoop wiki
At every new game after the MM is finished users add and developing a network plan for the game. So there can be as many plans as players. Let us say there are 5 plans. After the plans are added the vote-part begin. Every player makes a sign under his preferred plan with his name which means that he votes for the plan. Since there can be multiple good plans, the result of the vote could be suboptimal. If the results are 2/1/1/1/0, a plan wins with a plurality. This result does not necessarily choose the players' favorite option, so this page is for developing a new votesystem.
The idea of the new votesystem is you vote against a plan. After everyone have voted against a plan, the most "hated" plan gets removed. Then a new round of voting begins. This step is repeated until a plan is the winner for the game.
The new votesystem was tested in PSG210 with 7 different plans and about 7 votes per round.