The study, by the department's Bureau of Justice Statistics, was completed last April and posted on the agency's Web site after Bush administration officials disagreed over whether a press release should mention the racial disparities.

Traffic stops have become a politically volatile issue as minority groups have complained that many stops and searches are based on race rather than on legitimate suspicions.

The bureau's director, Lawrence A. Greenfeld, appointed by President Bush in 2001, wanted to publicize the racial disparities, but his superiors disagreed, a BJS employee said Wednesday. No release was issued.

Greenfeld has told his staff that he is being moved to a new job following the dispute, according to this employee, who spoke on condition of anonymity because he is not authorized to talk to reporters.

Greenfeld was not immediately available for comment. Justice Department spokesman Brian Roehrkasse would not comment on Greenfeld's status.

"When someone in law enforcement who is willing to speak the truth about racial profiling gets demoted for it, that's absolutely chilling," said Hilary Shelton, director of the NAACP's Washington bureau. "To manage any problem, we must first measure it."

Roehrkasse said, "There was no effort to suppress any information because the report was released in its entirety on the Web site." He added that 37 of 55 BJS reports issued in 2004 and so far this year were not accompanied by a news release.

Based on interviews of almost 77,000 Americans age 16 or over in 2002, the study drew no conclusions about the reasons for the racial disparities in post-stop treatment.

Casey Perry, chairman of the National Troopers Coalition, which represents state highway patrolmen, said he wasn't surprised about the percentage of motorists who are pulled over. "It's very interesting there was no racial disparity," he said, arguing that some regional studies which found profiling had been skewed by local demographics. More information would be needed to evaluate the post-stop data, he said.

Shelton said the BJS study found less racial disparity in traffic stops than a nationwide NAACP study between 1991-93, but said the figures for racial disparity in arrests and use of force were consistent with his group's findings.

The data showed that black, Hispanic and white motorists were equally likely to be pulled over by police; about 9 percent of each are stopped. Traffic stops were the most frequent form of police contact with the public; an estimated 16.8 million drivers were stopped in 2002.

The racial disparities showed up after that point:

_Blacks (5.8 percent) and Hispanics (5.2 percent) were much more likely to be arrested than whites (2 percent).

_Hispanics (71.5 percent) were much more likely to be ticketed than blacks (58.4 percent) or whites (56.5 percent).

_Blacks (2.7 percent) and Hispanics (2.4 percent) were far more likely than whites (0.8 percent) to report that police used force or the threat of it. Force was defined as when an officer pushed, grabbed, kicked or hit a driver with a hand or object. Also included were police dog bites, chemical or pepper spray or a firearm pointed at the driver, or the threat of any of these.

_Handcuffs were used on greater percentages of black motorists (6.4 percent) and Hispanics (5.6 percent) than whites (2 percent).

_Black and Hispanic drivers and their vehicles were much more likely to be searched than whites and their vehicles. Black motorists were searched 8.1 percent of the time; Hispanics, 8.3 percent; whites, 2.5 percent. Vehicles driven by blacks were searched 7.1 percent of the time; by Hispanics, 10.1 percent; by whites, 2.9 percent.

The study, first reported by The New York Times, said the interviews did not ask enough questions about circumstances — such as whether drugs were in plain view — or about driver conduct to "answer the question of whether the driver's race, rather than the driver's conduct or other specific circumstances," led to the search.

On the Net:

The study: http://www.ojp.usdoj.gov/bjs/abstract/cpp02.htm