Groton — Just more than a year after a study implicated Groton Town police as being more likely than most Connecticut departments to exhibit racial bias in traffic stops, a study of newer data by the same group has found no such correlation.

The newly released study, conducted by the Connecticut Racial Profiling Prohibition Project and the Institute for Municipal and Regional Policy at Central Connecticut State University, analyzed about 586,000 traffic stops made by state troopers and officers in 92 municipalities.

While its authors still offer recommendations for the department, they state "we anticipate no further need to monitor or review Groton Town stop data at this time."

In last April's report, the group singled Groton Town police out primarily because of data revealed in their so-called "veil of darkness" test, where the number of minority motorists stopped during the day is compared to the number of those arrested after dark, when race isn't easily discerned.

That data, which was gathered from Oct. 1, 2013, to Sept. 30, 2014, showed that Groton Town police stopped minority motorists across all racial and ethnic categories more often during daytime hours than nighttime ones.

According to the new report — which takes an in-depth look at all nine municipal departments pinpointed last year — it was later discovered that 601 of the 6,252 Groton Town stops analyzed last year, or about 9.6 percent, had defaulted to 12 a.m., even though many of them "clearly did not" happen at that time.

"It is impossible to determine how many of these stops actually may have occurred during the 'Veil of Darkness' sample period," the study states. "Thus it is also impossible to determine if the 'Veil of Darkness' results would have been affected positively, negatively, or at all, had the intervention times of these stops been properly recorded."

According to the study and to Groton Town police Chief Louis J. Fusaro Jr., the error was on Groton Town police and has since been resolved.

In the most recent report, which encompasses data from Oct. 1, 2014, through Sept. 30, 2015, Groton Town's stops didn't trigger concern in any of the study's measures or descriptive benchmarks, including the "veil of darkness" test.

Of the 5,899 people Groton Town police stopped during that time period, more than 77 percent were white non-Hispanic, almost 12 percent were black and about 8.5 percent were Hispanic.

In total, 23.7 percent of all drivers stopped were minority drivers, even though the resident driving population of Groton as a whole — including Groton City and Long Point Census tracts — is only 19 percent minority.

But Groton Town, the study notes, is "unique."

Although at least 40 percent of the submarine base's about 6,500 military personnel live on the base, the study states, Fusaro said many of those people tend to identify their actual home as being elsewhere during Census counts, thus skewing the town's population.

Additionally, with thousands of people driving in and out of General Dynamic Electric Boat and Pfizer Corp. each day — and using Groton Town roads while they're at it — Groton Town police stop a large number of people who aren't residents of any part of Groton.

Similarly, many nonresidents use Groton Town roads to get to and from the popular tourist village of Mystic, especially during the summer.

Indeed, 59 percent of drivers stopped in Groton Town weren't residents of Groton, according to the study. About 8.5 percent of those were out-of-state residents.

Still, authors of the study suggested Groton Town police take a look at their search policies and the types of traffic stops they conduct.

Statistics show Groton Town police — who search vehicles less frequently than the state average — search blacks and Hispanics twice as often as whites even though they find contraband on blacks (56 percent) and Hispanics (46.67 percent) at a lower rate than on whites (57.97 percent).

Further, Groton Town police conduct almost as many defective, inoperative or improper lighting equipment stops as they do speeding stops. The former, the study's authors wrote, "involve a higher level of officer discretion" and "can have an effect on the size of (racial) disparities."

Fusaro said his department has taken the findings seriously.

Since last year's study came out, Groton Town police have met with representatives of the group responsible for conducting the study several times.

Fusaro said he recently invited some of its members to come to Groton to train officers on the do's and don'ts of traffic stops, too.

"I want to know if we're doing something wrong," Fusaro said. "Racial profiling is unacceptable."

But because the deeper dive into the data so far hasn't revealed any blatant reason to update policies, Fusaro said, no changes have been made.

"I don't think we changed the way we're doing business," Fusaro said. "It's just more valid data this time around."

Data used in the study is collected electronically on a monthly basis as part of the updated Alvin W. Penn Racial Profiling Prohibition Act, which was first enacted in the state in 1999. The law prohibits law enforcement from stopping, detaining or searching motorists based on race, ethnicity or sexual orientation.

l.boyle@theday.com