PSTA hosted a ceremony Thursday at The Coliseum to officially deploy the buses. U.S. Rep Kathy Castor and City Councilman Jeff Danner, who chairs the PSTA board, were on hand.

The environmentally friendly, fuel-efficient buses cost $600,000 each and were purchased with federal grant money.

While the new buses are more expensive than standard diesel buses, they are 56 percent more fuel-efficient and can accommodate 14 additional passengers, according to a news release. The cost savings are expected to equalize the costs over the lifetime of the buses.

Four more hybrid buses, also paid for with federal funds, are on order and should be deployed by the end of the year, the PSTA release states.