Arlington County is operating 18 new mid-sized Metrobuses on the Washington Boulevard, South Courthouse Road, Carlin Springs Road and George Mason Drive bus routes.

As more Arlington commuters ride Metrorail, there is less of a demand for bus service on some routes. "Many of our citizens and residents felt the buses were too big with too few people on them," said E.L. Tennyson, the county's public works planning coordinator. "When they're running like they're supposed to, everyone should have a seat."

The buses, which are five feet shorter than the regular Metrobuses, are easier to maneuver on narrow streets and around tight corners. Their smaller and lighter size means they don't burn as much fuel as larger buses, get more miles to the gallon and reduce the weight load on Arlington streets.

Each mid-sized bus costs approximately $165,000, $35,000 less than the $200,000 price tag of the larger buses.

Eighty percent of the cost for smaller buses is paid by the federal government. About 14 percent is funded by the state. The county pays the remaining 7 percent, approximately $10,000 per bus, Tennyson said.

"Now it costs less for us to meet our bus needs," Tennyson said.

In mid-December, the county will begin operating an express bus from East Falls Church along Walter Reed Drive to Old Town.

"Saving 20 minutes will motivate people to use it," Tennyson said.