HARTFORD — Researchers at Central Connecticut State University say they have found some common factors in nine Connecticut police departments previously identified as having an issue with pulling over a disproportionately large number of minorities.

Their supplemental study, presented Thursday to a state advisory board on police profiling, looked at enforcement from October 2014 to September 2015 in Bloomfield, Meriden, Newington, New Milford, Norwalk, Trumbull, West Hartford, Wethersfield, Windsor, and the area patrolled by State Police Troop H.

It examined reasons for stops, where they were made, who was pulled over and other patterns.

The original report, which looked at all 106 departments in Connecticut, showed 14 percent of all traffic stops by police statewide from October 2014 to September 2015 involved black drivers, while black people of driving age comprised 9 percent of the population. Nearly 13 percent of traffic stops involved Hispanic drivers, while driving-age Hispanics comprised 12 percent of Connecticut residents.

Kenneth Barone, project manager for CCSU's Institute for Municipal and Regional Police, said the deeper dive into the nine departments found that in general, police had a higher concentration of enforcement efforts in areas where minorities live and drive.

"So then the next logical question is, why are the police in those areas?" he said. "Understanding the disparity has become relatively easy, the disparity is there because that is where the police are. The police are more likely to be in a predominantly black or Hispanic neighborhood than they are to be in a predominantly white neighborhood."

The study also found that most of those departments pulled over whites more often for hazardous driving violations, such as speeding, while black and Hispanic drivers are more likely to be pulled over for equipment violations, such as a broken light.

In some towns, minority drivers also were more likely to be searched, but less likely to be found with contraband, according to the study.

The study also took a look at every officer in the nine departments, comparing their traffic stops to a departmentwide benchmark, based on patterns of enforcement.

Of 294 officers with more than 50 traffic stops, the study identified 18 officers for whom stops were out of line with other officers in their departments.

Barone said the disparities don't prove racial profiling and don't take into account an officer's specific role in the department (such as an undercover officer) which might account for the disparity.

He said he hopes the departments use the data from the report to take a closer look at some standard operating procedures, such as where they choose to conduct traffic stops.

Department of Emergency Services and Public Protection Commissioner Dora Schriro said the state police find the data to be "exceptionally worthwhile" in examining what they do.

Messages seeking comment from other police departments were not immediately returned.