In its goal to reduce fleet emissions, the City of Madison, Wisconsin, has relied on biodiesel, hybrid-electric vehicles, electric vehicles, solar charging, anti-idling technology, and soy tires. But the one method resulting in more than 90% of the fleet’s carbon emissions reductions over the last few years is biodiesel, according to the city’s biennial fleet report.

Every gallon of biodiesel consumed by city fleet vehicles is renewable and grown and processed in Wisconsin. All diesel trucks use B-5 or B-20, depending on the season, unless temperatures are forecast to be below freezing. Biodiesel has no adverse effect on vehicle operations.

The city has a fleet of more than 100 hybrid vehicles, including police cars, and 54 electric vehicles, along with three solar charging stations. All new Fire Department ambulances will come with anti-idling technology, and soybean-oil-based tires on 170 police vehicles substitute petroleum use while supporting the soybean industry in the Midwest. The Goodyear tires have better traction than traditional tires, with improved flexibility in lower temperatures, according to the report.