More than 40 Bronzeville residents packed into a schoolbus last night to visit Mayor Richard M. Daley's house, demanding that city officials approve 500 vacant, city-owned lots in their neighborhood for affordable housing.

The residents, members of the Housing Bronzeville, want the City Council to approve their proposal before its August recess. Their goal is to have officials set aside the lots for middle-income families, ahead of the International Olympic Committee's decision on which city will host the 2016 games.

The activists say the Olympics could displace tens of thousands of residents in the historic Bronzeville neighborhood if the city does not commit the lots to homes for families making about $40,000 to $60,000 per year.

Their concerns echo those of other residents in South Side communities who have said they worry that an Olympic spotlight would lead officials and businesspeople in the city to gentrify historic black neighborhoods.

"The Olympics are known for displacement," says Valencia Hardy, a Bronzeville resident and member of the group. "Our goal is to get these vacant lots set aside so we can get these homes built for moderate-income families."

They traveled to the mayor's house after he did not show up, as they predicted, at a meeting of the group at New Haven Baptist Church last night. While they did not meet with Daley or a representative, they hung a large letter on the issue to a gate near his property.

Lance Lewis, spokesman at the mayor's office, confirmed that Daley declined Housing Bronzeville's invitation because he had previously accepted an invitation to another event at the same time. Lewis did not immediately specify the event that the mayor did plan to attend.

Molly Sullivan, spokeswoman for the Chicago Department of Community Development, says officials have worked with the group on its application to develop the vacant lots. She says it was incomplete, and that department officials spoke with Hardy and sent a full response to Housing Bronzeville's application by mail on Wednesday.

"We explained to them very clearly what they needed to do," Sullivan says. "We have certainly been more than willing to talk with them and respond to their needs."

She says developers and community groups often ask city officials for permission to develop Chicago's 15,000 or so vacant, city-owned lots. The City Council must sign off on such requests as part of a longer approval process, Sullivan says.

Housing Bronzeville's members say they are trying to avoid letting that process lag behind the IOC's decision, to come in October. They say they fear that if Chicago becomes the Olympic city before officials approve the lots for affordable housing, they will end up as more homes that are unattainably priced for the community's existing residents.

"The homes that are being built here are out of reach for the average Chicagoan," Hardy says.

The Rev. Jeffery Campbell, a fellow Housing Bronzeville member and pastor at Bronzeville's Judah Isrealite Christian Church, says he has seen a pattern of development that has pushed out families from other predominantly black neighborhoods in the city. He says Chicago is a Manhattan in the making, a place where monied investors could buy out longtime residents and change its character.

"All we're saying is, don't try to put us out of our homes," Campbell says. "If you price out your middle class, you take out the heart of your city."