The City of Rome, Italy could convert all of its 2800 buses to biodiesel by the end of 2008.
According to this article on Checkbiotech.org, a test of 200 buses will start the program:
Importantly, the accord covers not just the purchasing of the biodesel end-product but other stages of the supply chain including the growing of oilseed crops from which biodeisel is produced.
Farmers close to Rome have agreed to lift crop area devoted to rapeseed, soy and sunflowers from a few hundred hectares to 10,000 hectares, and to 20,000 if needed, to meet demand.
If fully implemented, the program could save 40,000 tons of carbon dioxide and emissions.