Washington State Ferries (WSF)/Washington State Department of Transportation (WSDOT) will shift the entire ferry fleet to low-sulfur diesel fuel, test ultra-low sulfur diesel fuel, and test biodiesel fuel—all steps that will improve air quality by reducing the amount of harmful substances in the ferries’ diesel fuel exhaust. The ferry system also has upgraded its vessels with more-efficient engines and made operational changes that have reduced fuel consumption and emissions, and will continue seeking new ways to improve fuel efficiency. As a result of all these changes, nearly 10,000 fewer tons of pollutants will be released into the air by ferry fuel emissions.