Black drivers in Lincoln and the state at large were stopped and searched at a more disproportionate rate than any other group of motorists in 2016, the Nebraska Crime Commission reports.
Lincoln police pulled over black drivers 5,137 times in 2016, comprising 10.9 percent of all stops, the commission's study found.
But African-Americans accounted for only 4.1 percent of the city's population, the study said.
By comparison, white drivers were pulled over in 77 percent of stops and Hispanic drivers, 6 percent. Those racial groups accounted for 83 percent and 6 percent, respectively, of Lincoln's population.
Lincoln police made the vast majority of traffic stops in Lancaster County, so findings for the county overall tracked with LPD's patterns.
Statewide, more than 38,000 black drivers were stopped by police, accounting for 7.7 percent of all drivers stopped.
The vast majority of these stops were for traffic violations.
The commission's report didn't offer any explanations for the traffic stop disparities.
"We cannot say definitively whether there is or is not racial bias in traffic stops, we can only point to seeming disproportionality," the report said.
Public Safety Director Tom Casady said Lincoln officials "are somewhat perplexed by the fact that the disparity has been increasing."
He and Police Chief Jeff Bliemeister are committed to impartial policing, Casady said.
He doesn't think racial animus is driving the traffic stop numbers because the department has taken measures to keep bigots off the force and trained incoming officers on detecting implicit biases.
Casady took issue with the report's use of a particular field of census data as a bad comparison measure.
That point includes only one race and underestimates the city's black population, he said. The African-American population in Lincoln is 5.7 percent when including people who identified as black or biracial.
And black drivers account for 6.2 percent of motorists involved in traffic crashes in Lincoln, he said.
He believes the remaining difference is driven by the realities of where officers police most and poverty.
Neighborhoods with the highest amount of police calls for service have the most officers deployed, he said.
Those areas also have the highest non-white populations, Casady said.
Income disparity is also playing a significant role in disproportionate stops of black drivers, he said.
A host of violations that may trigger a stop may relate to the driver's ability to pay, such as having fake license plates or expired tags, he said.
Minority drivers are turning up in more stops for those violations, Casady said.
There's also a racial disparity in arrest warrants, which officers are required by law to serve when they come into contact with the accused, he said. Most of those in Lincoln are for failure to appear, and in a recent analysis, black defendants accounted for 29 percent of warrants in Lincoln and Lancaster County, Casady said.
That most certainly is driving the higher rate, 4.3 percent, of black motorists arrested after being stopped, he said. Overall, 1.8 percent of all motorists were arrested by Lincoln police during stops last year.
True racial bias in policing would be reflected in other statistics such as car crash tickets, Casady said. But that isn't the case based on his analyses, he said.
Disparate amounts of minority drivers would be stopped by police during daylight hours compared to night-time hours if there truly were racial profiling in the department, he said.
But that's not the case, he said.
Members of the public can examine the problem for themselves by downloading traffic stop data on the city website's, opendata.lincoln.ne.gov.