Troco Coletivo, which translates to Payback Collective, is a Brazilian charity social experiment aimed at helping the poor gain access to public transportation. Similar to suspended coffee schemes or buy one give one tactics, Troco Coletivo lets people leave change via bright yellow stickers so needy people can ride the bus.
The charity social experiment hopes to integrate the city through cooperation. As those suffering from poverty walk the same streets as the wealthy, the Mark+ designed campaign encourages the wealthier to give back. Commuters can leave behind small change on the bus or at bus shelters through the yellow strips and pockets. While an element of trust is required for this charity social experiment to work, it also fosters a greater sense of community.