By early next year, visitors and workers in downtown Washington will be able to hop on trendy new buses linking some of the city's hottest tourist spots and major business centers, after Metro officials approved two routes yesterday.

For 50 cents, riders will be able to catch a bus and travel between Union Station, the new Washington Convention Center and Georgetown, with stops along K Street. Or they could go along Seventh Street between the new Convention Center, part of the Mall and the Southwest waterfront.

The service, dubbed the "downtown D.C. circulator," will operate separately from regular Metro buses, and a launch is planned in time for next year's National Cherry Blossom Festival, Metro officials said.

Buses will appear at stops every five minutes during rush hours and every 10 minutes during off-peak hours. Service is planned to run between 8 a.m. and 9 p.m. daily, with some variation by season.

The Belgian-made buses also will have big, tourist-style windows, including one in the rear, and District officials promised the new buses will have a unique look.

The routes are designed to fill the gaps in existing bus and rail lines, which are oriented toward commuting patterns that get people in and out of Washington's center rather than connecting them to its attractions, retail centers and offices. Boosting that sort of travel would be a boon to economic development and a convenience to users, District business leaders and transportation officials said.

Backers of the plan envision workers using the service to run daytime errands, grab a meal at a crosstown restaurant or shuttle between meetings. Tourists would have a cheap way to move between sites that surveys show they skip because they're hard and expensive to access. Conventioneers could take in more of the city beyond the seminars and exhibits that brought them to town.

"We see it as an opportunity to tie our city back together," said Dan Tangherlini, director of the District's Department of Transportation.

Similar downtown services operate with varying degrees of success in Denver, Los Angeles, Miami and a handful of other cities. In Denver, for instance, one route centered on tourist attractions didn't attract the desired number of riders and is being privatized, but a shopping district route is widely used.

Leaders in Washington said the service is another effort, such as building a K Street bus way and adding a light-rail line in Anacostia, designed to expand transit options and economic development.

"This is about creating a place where the economy buzzes all the time," said Joe Sternlieb, deputy director of the Downtown D.C. Business Improvement District, which pushed the plan. "If you want a really vibrant downtown, you don't want everyone thinking, 'I've got a meeting across town, so I've got to drive today.' "

Twenty-nine new buses needed for the service will cost between $12 million and $15 million and will be paid for with transportation funds the city had set aside, District officials said. Operation of the two lines will add 87 jobs and cost $4.5 million a year, $2 million each to be paid by the District and the federal government and $500,000 by city business leaders who pushed for the service.

Metro officials are hoping to attract 4.6 million riders a year. One of the keys to doing that is offering riders a more pleasant, convenient and cheaper trip than regular bus service, officials said.

To that end, they plan to buy 55-seat buses that have three street-level doors so people can get on and off quickly, similar to boarding Metrorail cars. In addition to offering frequent service, officials are planning to sell tickets at stops so riders can board directly and simply flash their tickets to checkers on the bus, rather than everyone filing, one by one, through a slow line at a single door.

"If we're going to get someone to walk out of a high-rent K Street office and ride the bus, we have to make sure they don't sit there and wait for it," Tangherlini said.

If, after at least a year, the first two lines prove successful and another $12 million to $15 million is available, District officials said, they would add two more routes that would primarily circle the Mall.

The 29 buses, similar to this one, on the two new routes won't be the normal Metro buses. They will include three street-level doors and 55 seats each.One bus route will connect Union Station and Georgetown. The other will link the Convention Center and waterfront.