HARRISBURG – Pennsylvania State Police stopped drivers at about the same rate regardless of their race or ethnicity, according to a 2023 study of traffic stops.
An analysis published last week by criminologist Robin Engel and other data scientists also found only minor differences in the results of traffic stops. There were hardly any differences in the number of arrests, tickets and warnings between different racial and ethnic groups.
The study found a small difference in the rate of discretionary searches initiated by a police officer based on probable cause, reasonable suspicion or the driver’s consent. 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 accounting for criminal records, the analysis found.
Despite the continued disparity, this represents a decline in racial and ethnic disparities in stop-and-frisk outcomes compared to the previous year, when Engel and his researchers found that black drivers were 1.9 times more likely to be subjected to a random search.
In more than half of the stops, state police found contraband such as drugs, drug paraphernalia or weapons during a discretionary search. The researchers found some moderate racial and ethnic differences in seizure rates, although these were also lower compared to previous years.
During a voluntary search, about 61% of white drivers were found to have contraband, compared with only 44% of black drivers and only about 32% of Hispanic drivers. For other types of voluntary searches, racial differences were minimal.
The report recommends that state police continue to review body and dashboard camera footage during traffic stops as part of their accountability efforts.
Overall, the analysis found that legal variables – such as criminal records or speeding violations – were stronger indicators that a stop would result in an outcome such as a warning, summons, search or arrest.
The investigation continues the agency’s longstanding partnership with Engel, who previously worked for the State Police between 2002 and 2010. Engel resumed her work with the department in 2021 after Spotlight PA discovered that the State Police had quietly stopped collecting data on traffic stops.
In the first year, significant data collection problems prevented researchers from analyzing the stops for differences. Last year, Engel found differences in search and seizure rates.
The latest data collection was the most comprehensive and thorough to date. Although officers stopped more drivers than ever, they were able to reduce both the number of unrecorded stops and the number of blank fields (that officers did not fill in) compared to previous years.
“We continue to exceed expectations regarding the reliability and validity of this data,” she said at a press conference.
Engel’s analysis does not use “resident population” to compare and reveal differences. In previous years, she had found that resident population is a flawed measure because where people live does not necessarily correspond with where they drive.
This year, as an alternative, researchers conducted a “veil of darkness” analysis that focuses only on stops that occur in the evening hours, when the driver’s race is difficult to determine. They found that black and Hispanic drivers were 1.1 times more likely to be stopped in the evening, “which, despite its statistical significance, does not represent a substantively meaningful difference,” the report said.
Engel and the researchers also examined the reasons why police officers stopped drivers to address public concerns that “certain types of minor non-moving violations are disproportionately used against drivers of color for ‘sham’ purposes,” they wrote in the report. These could include a broken tail light, a cracked windshield or other problems with the vehicle.
This analysis also found that there were little racial differences in these types of controls.
Patrol officers collect information about stops using an electronic form that includes fields for the circumstances of the stop, such as time of day, location and reason for the stop, driver demographics, result of the stop, and information identifying the patrol officer, such as assigned station.
State police must report the gender, age, race or ethnicity and zip code of the person stopped, as well as whether the person exhibited “obedient or unruly behavior.” Race or ethnicity is recorded based on the officer’s perception.
Officers have further refined their protocol to ensure all stop information is captured and have added additional fields and data validation measures to the form following the 2022 report.
Other local departments, many of which do not currently collect traffic stop data, will likely follow this model when a new law takes effect in 2025 requiring police departments across the state of Pennsylvania to collect similar data.
That law also prohibited the public from requesting traffic stop data under a right-to-know law. Spotlight PA made such a request in May, but state police denied it, citing an exception in the law that allows agencies to deny requests for records related to a non-criminal investigation.
The requirement was included in a law that will also allow patrol officers and other law enforcement officers to stop drivers for using cell phones starting next year.
Members of the Legislative Black Caucus fear that the cell phone ban would give police an excuse to stop people of color. In doing so, they share the concerns of the researchers, which they address in their report.
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