The chief executives of more than 200 cities were converging on Chicago for this weekend's annual meeting of the U.S. Conference of Mayors, greeted by blooming flowers, a pristine lake dotted by sailboats and a man named recently by Time magazine as one of the very best mayors in America.

But the visitors come at the end of yet another tough week for Mayor Richard Daley as scandal, wrongdoing and multiple investigations simmer just behind Chicago's sparkling facade.

While the mayors discussed homeland security and making cities competitive Friday at the Chicago Hilton and Towers Hotel, a former Transportation Department foreman pleaded guilty in federal court to diverting as many as 100 truckloads of city asphalt valued at up to $60,000 to private contractors.

The day before, two figures in the Hired Truck Program scandal were in court.

Martin McDonagh, a trucking company owner, was sentenced after pleading guilty to lying to the FBI about paying off two city employees to obtain business.

In another courtroom, Joseph Ignoffo admitted that he paid at least $23,000 in cash, gift certificates and campaign contributions to officials in four city departments to keep his trucks running. Some of the money wound up in the campaign fund of Cook County Commissioner John Daley, the mayor's brother, authorities said.

McDonagh and Ignoffo are among 27 charged in connection with the Hired Truck probe, an investigation that promises to produce even more defendants.

There was more bad news Friday, when the city fired John Quinn, a top Zoning Department official, because he refused to answer questions about the issuance of a building permit for a condominium in a zone reserved for manufacturing, officials said. Two senior Buildings Department officials had resigned after facing questions on their involvement in the matter.

Blocks away from City Hall, however, Daley reveled in a bubble where no one knew or cared much about his recent problems. To help make sure it would stay that way, Daley's press handlers warned reporters that only questions about the gathering were allowed at a news conference with other mayors.

The focus for many visiting civic leaders was on how best to emulate Daley's Chicago.

A Chicago police camera was proudly displayed outside a meeting room, its blue lights flashing and a uniformed officer standing next to it.

Daley told mayors that he had installed the cameras, over the objections of some who saw them as intrusive, because "the street, the alley, the sidewalk belong to the public."

"We lead the way," Daley said. "We know we have a good Police Department."

The decline in violent crime in Chicago under Daley is "just phenomenal," said Beverly O'Neill, mayor of Long Beach, Calif., and vice president of the conference.

Daley, who once headed the mayors group, is admired by his peers across the country, said Harvey Johnson Jr., mayor of Jackson, Miss. Johnson said his city will follow Chicago's lead with police surveillance cameras.

"I'd like Millennium Park plopped down right in the middle of my downtown," said the conference president, Mayor Donald L. Plusquellic of Akron.

"He is viewed as very creative, a very committed leader of this community," said William Horne, city manager of Clearwater, Fla. "We look to follow Chicago's path in many areas where they have decided to be bold."

Cindi Canary, executive director of the Illinois Campaign for Political Reform, said visiting mayors can credit Daley, but they should also consider the cost of corruption that the administration is struggling to deal with.

"I suppose I would tell them to enjoy our city because it truly is beautiful and it truly has been transformed," she said. "But I would tell them they need to look beyond the wrought iron and the flowers and the parks ... the `city that works' isn't working so well right now."