Data analysis

Analysis of Massachusetts data finds no support for patterns of racial disparity in traffic stops – Fall River Reporter

BOSTON — Today, the Executive Office of Public Safety and Security released a report on the results of a baseline analysis of police traffic stop data conducted by a team of researchers from universities in State of Salem and Worcester. In 2019, the Massachusetts Legislature passed and Governor Baker signed a law requiring hands-free use of cell phones while driving that prohibits drivers from using electronic devices, including cell phones, unless the device is in hands-free mode. The law also required an annual analysis of police traffic stop data and a public report of its findings.

To meet this requirement, EOPSS contracted with Salem State University to analyze local and state police stop data and develop a comprehensive report. The data was provided by the Motor Vehicle Registry based on information collected from all Massachusetts Uniform Citations issued. Based on the uniform citation data, the research team performed an aggregate analysis of all stopped motorists, including age, gender, and race. The study also looked at the date and time of the offence, the location, whether a search was initiated and whether the stop resulted in a warning, citation or arrest.

“A significant feature of the Hands-Free Driving Act established a research requirement that provides factual information about the factors surrounding traffic stops and to identify any potential patterns of racial disparities. The annual study will contribute to our ability to better understand police interactions with the public and to ensure that the Commonwealth Highway Code is applied impartially, fairly and justly,” said Public Safety Secretary Terrence Reidy.

The goal of the baseline study was to examine possible racial disparities in traffic stops and better understand potential patterns. The study included ten months of shutdown data from February 2020 through December 2020, evaluating information at the state and municipal level. Researchers analyzed law enforcement agencies that carried out 100 or more traffic stops, representing more than 80% of the 350 law enforcement agencies across the Commonwealth.

According to the data, Massachusetts law enforcement conducted a total of 425,702 traffic stops during the study period. Municipal police carried out about 60% of traffic stops, while state police carried out 40%.

The statewide analysis found that of the arrested drivers, 65% were male, 34% were female, and about 1% were non-binary. The average age of arrested drivers was 37, with 39% being 29 or younger and 61% 30 or older. White drivers accounted for 65% of traffic stops, while black motorists accounted for 16%. Hispanic drivers made up 15% of stops, and 4% were either Asian, Asian-Pacific, Native American, Middle Eastern or Pacific Islander. Almost 68% of the drivers stopped were not residents of the community where the stop took place.

The researchers applied ‘Veil of Darkness’ (VoD) analysis to study the racial distribution of traffic stops. The VoD method, first developed in 2006 by renowned researchers Jeffrey Grogger and Greg Ridgeway, is considered the gold standard of analysis for identifying patterns of racial differences. The VoD test compares stops made in the dark to those made in broad daylight, based on the logic that police officers are less likely to be able to determine a driver’s course at night than during the day.

Statewide VoD analysis found no support for patterns of racial disparity in traffic stops. According to the report, non-white motorists are 36% less likely to be stopped in daylight (when they could potentially be seen and racially profiled for a stop) than in the dark.

Of more than 280 police departments with enough stops for meaningful analysis, the researchers found that non-white drivers were more likely to be stopped during the day than at night in three cases: the H-3 Troop of the Massachusetts State Police in Foxboro and the Hadley and Ludlow Police Departments. The researchers caution that this statistical significance could come from several factors beyond the scope of the data, including whether the stop was discretionary or due to a radio call, motorist behavior or the triggering violation.

“This basic research should serve as a starting point for deeper understanding, ongoing discussions, and deeper reflection. We caution that our findings do not support racial profiling and that any statistically significant incident could have a variety of explanations other than officer bias,” said Salem State researcher Gina Curcio, Ph.D.

As required by law, EOPSS will consult with the Massachusetts Attorney General’s Office to determine next steps based on the findings of the research, including whether additional data collection or training is required for certain law enforcement agencies. law.

The EOPSS will convene three virtual public hearings to present the analysis and accept public testimony regarding the report. The schedule of public hearings includes:

Monday February 28, 2022 from 10 a.m. to 12 p.m.
Tuesday, March 1, 2022 from 3:30 p.m. to 5:30 p.m.
Wednesday March 2, 2022 from 1 p.m. to 3 p.m.

Written comments will also be accepted until 5:00 p.m., Wednesday, March 2, 2022. They can be emailed to [email protected] or mailed to: Michaela Martini, Criminal Justice Advisor, Executive Office of the Public Safety, One Ashburton Place, Room 2133, Boston, MA 02108.