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HARRISBURG — Pennsylvania State Police pulled drivers over at about the same rate regardless of the motorists’ race or ethnicity, according to a study of traffic stops made in 2023.

Released last week, the analysis by criminologist Robin Engel and other data scientists also found little discrepancy in the outcomes of traffic stops, noting negligible differences in the rate of arrest, citations, and warnings across racial and ethnic groups.

The study did find a small difference in the rate of discretionary searches, which are initiated by a trooper based on probable cause, reasonable suspicion, or the consent of the driver. These searches accounted for 2.2% of the nearly 450,000 stops conducted in 2023. Black drivers were 1.46 times more likely to experience such searches than white and Hispanic drivers after controlling for criminal history, the analysis found.

Despite the lingering disparity, this marks a decrease in racial or ethnic differences in stop outcomes from last year, when Engel and researchers found Black drivers were 1.9 times more likely to get a discretionary search.

State Police found contraband such as drugs, drug paraphernalia, or weapons in more than half of stops with a discretionary search. Researchers found some moderate race and ethnic differences in seizure rates, though those were also lower compared to prior years.

When troopers conducted a consent search, contraband was found for about 61% of white motorists compared to about 44% for Black drivers and around 32% for Hispanic drivers. In other types of discretionary searches, the racial differences were minimal.

The report recommends State Police continue to review body and dash camera footage of stops as part of accountability efforts.

Overall, the analysis found legal variables — such as criminal history or speeding — were stronger indicators that a stop would produce some kind of result, such as a warning, citation, search, or arrest.

The research continues the agency’s longstanding partnership with Engel, who first worked with State Police between 2002 and 2010. Engel renewed her work with the department in 2021 after Spotlight PA found State Police quietly ceased collecting data about traffic stops.

In the first year, significant issues with collecting data prevented researchers from analyzing the stops for disparities. Last year, Engel found disparities in discretionary searches and seizure rates.

The latest data collection effort was the largest and most robust to date. Even as they stopped more drivers than ever, troopers improved rates of both unrecorded stops and blank fields — those the trooper failed to fill out — compared to prior years.

“We just continue to excel in terms of the reliability and validity of these data,” she said at a news conference.

Engel’s analysis does not use “residential population” to compare and discover disparities. In prior years, she has noted that residential population is a flawed metric because where people live is not necessarily the same as where they drive.

This year, the researchers conducted a “veil of darkness” analysis as an alternative, which focuses only on stops that occur in evening hours when it is difficult to see the driver’s race. They found that in the evening, Black and Hispanic drivers were 1.1 times more likely to be stopped, “which is not a substantively meaningful difference despite its statistical significance,” according to the report.

Engel and the researchers also examined the reasons troopers stopped drivers to address public concerns that “certain types of low-level, non-moving violations are disproportionately used against drivers of color for ‘pretextual’ purposes,” they wrote in the report. These could include a broken taillight, cracked windshield, or other issue with the vehicle.

This analysis also showed little discrepancy by race for these types of stops.

Troopers collect information about stops using an electronic form with fields for circumstances surrounding the stop, such as time of day, location, and reasons for the stop; demographics of the driver; outcome of the stop; and trooper-identifying information such as assigned station.

State Police must report the gender, age, race or ethnicity, and ZIP code of the people they pull over, as well as whether the person exhibited “compliant or resistant behavior.” Race or ethnicity is recorded based on the officer’s perception.

Troopers have continued to fine tune their protocol to ensure all information about the stops is collected, adding additional fields and data validation measures to the form after the 2022 report.

Other local departments, many of which do not currently collect traffic stop data, are likely to follow this model when recent legislation requiring police departments across Pennsylvania to collect similar data takes effect in 2025.

That legislation also barred the public from requesting traffic stop data through a Right-to-Know Law request. Spotlight PA made such a request in May, but State Police denied it, citing an exemption in the law that allows agencies to reject requests for records related to a noncriminal investigation.

The requirement was included in legislation that also allows troopers and other police officers to begin pulling drivers over for using cellphones starting next year.

Members of the Legislative Black Caucus worry the cellphone ban will give police a pretextual reason to stop people of color, echoing the concern researchers addressed in their report.

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