Four new 37-seat EZ-rider II buses have joined the Maui Bus fleet.

The buses, manufactured by ElDorado National Co., were purchased by the county using $500,000 in Federal Transit Administration funds. Three more new EZ-rider buses are scheduled to arrive in June, county officials said.

Although the county owns the vehicles, Roberts Hawaii is under contract to operate the public transit system's 30 buses of various sizes.

Maui's fledgling bus system overcame a rocky start in 2006 by offering expanded and more frequent service and a more convenient transfer hub at Queen Ka'ahumanu Center in Kahului.

County Transportation Director Don Medeiros said ridership is up 35 percent from last year and that up to 1.4 million boardings are expected this year.