SOUTH BEND, Ind. (AP) — South Bend’s public transit agency is upgrading its fleet for the first time in 16 years with new natural-gas fueled buses.

The South Bend Tribune reports that Transpo is already using ten of the cleaner-burning and cost-efficient buses. Six more will be on the roads soon and the agency has another three that are on order and are scheduled to be delivered in early 2016.

The new buses run on compressed natural gas and can each accommodate more riders than the agency’s older diesel-powered buses. Each one costs around $450,000.

The agency says it plans to upgrade the entire fleet over the next five years as funding is made available.