PHOENIX (AP) November 8, 2007 — A study of traffic stops conducted by Arizona Department of Public Safety officers found evidence of possible racial profiling by officers, although researchers cautioned that other factors may be responsible for high rates of stops and searches of minority drivers.

The University of Cincinnati report shows Highway Patrol officers were more than twice as likely to search vehicles driven by Hispanics and blacks than white drivers during 2006. Minorities also were far more likely to be arrested or to receive multiple traffic citations.

Hispanic motorists were the most likely to be searched, arrested, cited and to receive multiple citations and the least likely to get off with warnings.

The 223-page report was done to satisfy terms of a 2006 settlement of a lawsuit filed by the American Civil Liberties Union and criminal defendants that accused officers of targeting minority motorists along interstate highways near Flagstaff.

DPS settled the 2001 case after telling the court it had lost or destroyed two years' worth of traffic-stop data. It agreed to gather detailed information on traffic stops by all officers for analysis.

The report says the 2006 data clearly shows more minorities are being stopped but that a firm conclusion about racial profiling should be "tempered" because ethnic-enforcement disparities "may be explained by legitimate factors unmeasured by these data." Such factors include severity of the traffic offense, motorist attitudes and socio-economic status.

The research team, headed by Professor Robin S. Engel of the university's Policing Institute, recommends more data-gathering, a series of focus groups and other steps to gain a better understanding of what's responsible for the higher minority numbers.

Engel was a consultant for the state in the lawsuit, and the DPS is paying for her three-year research project. She said the findings mirror racial disparities common to police organizations throughout the nation, but said it's not possible to conclude that discrimination is to blame.

"Until I can get into the mind of an officer, I cannot determine whether he or she is making stops based on race. No researcher can do that," Engel said. "It could be officer bias. I haven't ruled that out."

But Dan Pachoda, legal director for the ACLU in Arizona, said the new data back up finding by plaintiffs who brought the lawsuit.  "It clearly indicates racially biased decision-making," he added.

Fred Solop, director of the Social Research Lab at Northern Arizona University and a consultant for plaintiffs in the lawsuit, conducted his own analysis of the DPS data, focusing only on traffic stops along interstates.

Solop said his breakdown shows blacks, Hispanics and American Indians are 2 1/2 times as likely as whites to be searched by DPS officers. He also found the stops were longer for minorities even when no search was conducted. Solop rejected the University of Cincinnati researchers' suggestion that unknown factors, rather than prejudice, could account for the statistical disparities.

"The data is very clearly showing . . . different racial and ethnic groups are being treated unequally," Solop said.

DPS Director Roger Vanderpool said the agency is committed to safeguarding citizens' rights and that any racial profiling would violate department policy.