Do traffic stops in high-crime areas deter crime and protect public safety?
For many police agencies, the answer is obvious. Making officers a “visible” pro-active presence on the streets has long been regarded as a valid law enforcement strategy.
But when a group of researchers decided to test that proposition, they came up with a different answer.
The researchers, in a paper for the Stanford Computational Policy Lab, analyzed traffic stops during 2017 in Nashville, Tenn., where police have the notable distinction of making more traffic stops per capita than anywhere else in the nation, and which was the subject of a 1999 report by the American Civil Liberties Union, “Driving While Black,” that noted the disproportional impact the strategy has on African-Americans.
They found, instead, that traffic stops “had no discernible effect on serious crime rates, and only infrequently resulted in the recovery of contraband of a custodial arrest.”
In the paper, commissioned by the city of Nashville, and formally presented this week as part of a series for the New York University School of Law’s Policing Colloquium, the researchers reported that the majority of the 246,000 traffic stops by Nashville police they reviewed were for “non-moving violations,” such as broken headlights, or expired driver’s registrations—and suggested these could be cut back sharply with no impact on public safety.
Nashville police, in fact, had already reduced the number of traffic stops by the time researchers begun studying them, but the number was still far higher proportionally than other U.S. cities—and officers overwhelmingly stopped more African Americans than whites, the researchers said.
Black drivers were stopped 44 percent more often overall than whites per driving age resident, but for non-moving violations the imbalance was as high as 68 per cent.
The researchers cautioned this did not necessarily imply racial basis. It was mostly because the stops were focused on high-crime areas where many African Americans reside, they said.
“This policy of concentrating stops in high-crime areas may be predicated on the belief that that traffic stops are an effective tactic for reducing burglaries, robberies and other criminal activity,” the paper said.
“We find, however, no immediate or long-term impact of traffic stops on serious crime.”
Only 1.6 percent of the stops, the researchers found, resulted in “custodial arrests”—usually for license violations or drugs.
They suggested Nashville could safely reduce the number of stops, in line with the strategies taken by other cities such as the New York Police Department, which reduced ‘stop, question and frisk” pedestrian stops from nearly 700,000 in 2011 to 11,000 in 2017.
Such a policy could also have beneficial consequences for police-community relations, the researchers added, noting that frequent stops can “create stress” as well as result in fines and fees that are a burden for low-income residents.
But they warned that Nashville cops would need to make significant cuts to bring them into line with practices of other cities that have already begun to rethink the strategy.
“A reduction of even 50 percent in non-moving violation stops would still leave the city’s overall stop rate twice as high (or higher) than other peer cities,” the paper said.
“A more substantial 90 percent reduction in such stops would put Nashville on par with peer cities with the highest stop rates..and would have significant impact on the day-to-day lives of Nashville residents.
The authors of the paper were Alex Chohlas-Wood, Sharad Goel, Amy Shoemaker, and Ravi Shroff.
Read the full paper here.