A disproportionate number of black people in the District are arrested for minor violations that include smoking marijuana in public, driving without a license and gambling, a study from two watchdog groups found.

Advocacy groups have reached similar conclusions in past years in Washington and in other cities. But this report’s authors said the new data, covering the years 2013 through 2017, shows the disparities are spread across the entire District and not limited to wards with high crime rates.

The study was done by the D.C. office of the American Civil Liberties Union and a consortium of groups advocating transparency, called Open the Government. It is based on five years of arrest statistics provided by D.C. police after a Freedom of Information Act request.

Disparate arrests “are happening throughout the entire city, which raises serious questions about how this department is policing,” said Michael Perloff, a lawyer with the District’s office of the ACLU.

Perloff said Mayor Muriel E. Bowser’s plan to expand the police force should be postponed “until she determines why officers are policing the way they are.” He said the report raises the possibility of whether some arrests “could arise from discriminatory decisions by officers.”

Kevin Donahue, the deputy mayor for public safety and justice, said the District is addressing some issues, such as directing officers to issue citations instead of arrests for more crimes. That includes smoking marijuana in public, illegal even after possession of small amounts of the drug was decriminalized in February 2015.

“That the vast law enforcement and justice system touches the lives of communities of color more than others is not unique to D.C.,” said Donahue, who spoke on behalf of the Democratic mayor’s administration and the police department. He noted that one question is whether there are laws “that no longer reflect our D.C. values that the District should change.”

The report, made public Monday, says blacks accounted for 86 percent of the total arrests over the years examined, even though they make up slightly less than half of the District’s population. The report says the disparity held true across 90 percent of the District’s census tracts, “including the whitest parts of the city.”

The report focused on arrests for what the writers called minor offenses, such as public consumption of marijuana, gambling, violating a noise ordinance and having open containers of alcohol in public. In each of those categories, the report says blacks accounted for at least 76 percent of arrests. For gambling, it was 99 percent. The data reflects the most serious offense the officer charged.

Of particular concern, the ACLU and the open-government group said, were arrests for people driving without licenses. Of the 10,305 people arrested for that offense over the years studied, the report says that nearly 80 percent were black.

Officers pulling over a vehicle for a suspected infraction do not know whether a driver has a valid license until after the stop. The ACLU says it was able to get a racial breakdown only of those arrested and not of all drivers stopped by police. The group said that makes it impossible to assess whether more black drivers are pulled over for possible traffic infractions.

The groups said police are required to turn over such racial data as part of a law enacted in 2016 and have complained the department has yet to fully comply. The two sides are in litigation over that matter and several others related to the law.

“If it’s intentional, subconscious or a lack of training, we need to address it,” said Lisa Rosenberg, the executive director of Open the Government, referring to traffic stops. “The police should answer for the disparity, and they should explain to us what they are going to do about it.”

Donahue said that with traffic enforcement and other areas where officers “take proactive enforcement,” the police department tries to ensure the operations are spread evenly across the District. He said police will use arrest data to determine whether that model needs to be tweaked or updated.

The study also raised concerns about arrests for public consumption of marijuana. While possession cases plummeted after decriminalization, the study found the number of people arrested for public consumption now exceeds those arrested before the law took effect. Black people accounted for about 80 percent of the arrests, according to the study.

The report says the marijuana law has a built-in disparity, making it “illegal to do in public what is legal to do in private,” thereby penalizing “those who have less access to private property.” That includes residents of federal government-funded housing, where using marijuana or any other illegal drugs can lead to eviction.

The reports likens offenses such as making loud noise and drinking on the street to “poverty crimes” and said that “given the high correlation between race and poverty in the District, arresting people for crimes that are disproportionately committed by people who are poor will result in more arrests of black residents.”

Donahue said city officials recognize the disparity, particularly regarding arrests for public consumption of marijuana. “I think it relates to a lack of education as to what was legalized and was not,” he said.

The deputy mayor said police officers were told last year to issue citations instead of arrests for marijuana consumption. It is not yet clear whether that shift has had an impact. But he also said blame for much of what the report found should not be shouldered entirely by police.

“It is a discussion that at its root is about equity in our society,” Donahue said, noting risk factors such as poverty, substandard housing, lack of education and unemployment. “The risk factors are not distributed equally.”