When it comes to issuing tickets or levying fines for driving violations, a new study reveals unequivocal bias against minorities.
The research, published in the journal Science and based on novel use of high-frequency location data to measure location and speed, finds police were 33% more likely to issue speeding violations to minority drivers than their white counterparts and charge 34% more expensive fines. That’s despite finding no discernable differences in speeding behaviors or traffic violations.
The researchers, whose aim was to examine the full extent of racial profiling in the enforcement of speed limits, teamed up with the rideshare platform Lyft. The sample consisted of Lyft drivers in Florida between 2017 and 2020.
Justin Holz, assistant professor at the University of Michigan’s Ford School of Public Policy, and colleagues from multiple institutions linked high-frequency location data (GPS pings communicated from a driver’s phone) of motorists with official government records on their speeding violations and inferences of their race or ethnicity. Those inferences are based on a model that relates self-reported information of the 45.7% of drivers who are registered voters in Florida to a picture that each driver submits when they apply to drive for Lyft.
The researchers say that to their knowledge, this is the first study to construct such a dataset. Previous studies had shown that racial minorities often receive harsher penalties during police stops, but it had been difficult to determine whether this reflected racial profiling because the events leading up to the stop were unclear.
“By analyzing detailed Lyft data—including driver speed and location—we were able to observe behavior before any police interaction,” Holz said. “This allowed us to isolate the effect of race on both the likelihood of being stopped and the penalties imposed.”
Holz notes that white and minority drivers have statistically indistinguishable rates of accidents and reoffending, which suggests that statistical discrimination doesn’t underlie evidence of racial profiling. Rather, he says, it suggests prejudice or animus by police against minority drivers.
“With no other justifications for the unequal treatment, we concluded that at least some police officers are racially profiling because they prefer to enforce the law when a driver belongs to a racial or ethnic minority,” Holz said.
Among the study’s limitations: Lyft drivers are incentivized to avoid traffic violations and the sample is less prone to speed. So the analysis examines only about 1,400 citations for speeding, which limits the scope of analyses—though researchers could build on the work.
As far as recommendations are concerned, the authors say appropriately located automated technologies, such as speeding cameras, could help reduce selective enforcement.
Also, since auto insurance rates typically rise when drivers are cited for speeding and the findings show such citations aren’t blind to drivers’ race, accounting for race in the relationship between citations and insurance rates could lessen the effect of racial profiling.
Read the study here.
This post was written by Jeff Karoub, senior public relations representative for Michigan News
