Tens of thousands of people in Washington, shrugging off the gray skies and intermittent rain, turned out yesterday to celebrate any number of things - a groundbreaking, a dedication and a good old-fashioned parade.

The parade, an annual affair honoring the Washington area school safety patrol program, drew the most spectators. Park Police said 44,000 people lined the 10-block route along Constitution Avenue and another 10,000 children in 134 patrol units marched in the parade.

Also featured was the mounted unit of the Park Police, a squad of D.C. policemen on motorcycles and William De Rosa, who became the area's first safety patrol captain in 1926. He rode in a car yesterday.

The safety patrol members all wore the bright orange belts and silver badges that make them conspicuous at school crossings, and their parade also managed to tie up a considerable amount of downtown traffic.

Groundbreaking ceremonies for the new O Street Market marked the beginning of a new project for one of the poorest sections of the city. The dedication of a housing project on 14th Street NW illustrated the successful cooperation of the city, the federal government and private firms.

At a festival at 17th and N Strees NW, puppeteers and magicians and mimes joined local preservationists to "celebrate contemporary living in a historic district," as one sponsor put it. On New York Avenue, crowds gathered to watch a New York artist sandblast a map of the city on the wall of a downtown office building.

Also in keeping with the season, the gathering of crowds was immediately followed by a gathering of politicians.

Both D.C Mayor Walter Washington and D.C. Del. Walter Fauntroy were at the O Street market and 14th Street ceremonies, and both delivered modified versions of the same speech at both affairs.

The theme they sounded for the day was that both projects represent dreams that have come true, that the city seems "to have come back from ashes to a new day, an awakening." As Mayor Washington said at the Columbia Heights Village dedication. Both men also had kind words for each other, a rarity in this election year.

On 14th Street, more than 100 people jammed into a room at Columbia Heights Village, a 406-unit highrise and garden apartment complex at 14th Street and Columbia Road.

Tenants have been selected for all of the units - more than 8,000 applied, according to H.R. Crawford, whose company manages the project - and most have already moved in. The low and moderate income tenants in the buildings receive government subsidies to enable them to pay rent. Funds also have been sought to help them pay the high utility costs they have faced in recent months.

According to a brochure, 97 percent of the tenants are black, and nearly one-third of the apartments are occupied by families displaced from other buildings, the elderly and the handicapped. About 40 percent of the tenants qualify for rental assistance. Nearly 300 children are expected to live in the complex when it is fully occupied, and the gross monthly income for two-thirds of the residents is less than $750 a month.

The O Street Market project between 7th, 9th, O and P streets NW, will include a new bank; a drug store; a supermarket that will be jointly owned by Giant Food, the D.C. Development Corp., and the Shaw Community Development Corp., and a pedestrian mall and parking lot.

The O Street Market, formerly a bustling shopping complex that has been closed since riots devastated it in 1968, is to be reopened. Stalls will be rented to farmers and others to sell fresh fruits and vegetables, meat and other items.

In the midst of his remarks at O Street Market, Fauntroy broke into tears, rubbing his eyes and pausing frequently. He sang "The Impossible Dream".

"I grew up in this neighborhood," Fauntroy told the several hundred people standing in the mud outside the cavernous red market. "They called this the wickedest precinct, shameful Shaw."

His remarks at O Street and on 14th Street included biblical references and the lyrics to "Tobacco Road."

"Lord, we ain't what we wanna be and we ain't what we gonna be, but thank God we ain't what we was," Fauntroy said was a statement that summed up his feelings.

Mayor Washington told the crowd at O Street, "All the things they said couldn't happen are happening." The city must be doing fine if we're running out of sewer space (for building expansion), because something's got to be going there. You understand what I mean?"

By the time the festivities began on N Street, between 17th and 18th streets, the sun had made a strong comeback, chasing away many of the clouds. That block, a street of graceful brick buildings that include apartments, houses, offices and two inns, was once the home of Franklin Roosevelt and Joseph McCarthy.