A police officer in Colorado poses with a body camera. (Rick Wilking/Reuters)

The Department of Justice plans to launch a pilot program aimed at expanding the use of body cameras worn by police officers across the country.

These cameras are meant to help local and tribal law enforcement agencies improve relationships with the public, a goal that follows a year of protests across the country aimed at the way police officers use lethal force, particularly toward black men and boys.

“This body-worn camera pilot program is a vital part of the Justice Department’s comprehensive efforts to equip law enforcement agencies throughout the country with the tools, support, and training they need to tackle the 21st century challenges we face,” Attorney General Loretta Lynch said in a statement.

Police in Philadelphia started testing body cameras on Dec. 1. The department says up to 31 officers began wearing the devices to record interactions with civilians. (AP)

Lynch said body cameras were a way to benefit the public as well as police officers.

“Body-worn cameras hold tremendous promise for enhancing transparency, promoting accountability, and advancing public safety for law enforcement officers and the communities they serve,” Lynch said.

Attorney General Loretta Lynch. (J. Scott Applewhite/AP)

Federal officials plan to award nearly $20 million in funding to dozens of departments, about a third of them small law enforcement agencies. In addition, another $1 million will be set aside so that the Bureau of Justice Statistics can figure out how to study the actual impact of these cameras.

A White House task force on policing, created in the wake of the unrest last year in Ferguson, Mo., New York and other cities, issued a report in March that did not recommend that officers have to wear body cameras. But it said that these cameras have been shown to reduce use of force by police and complaints against officers.

“Now that agencies operate in a world in which anyone with a cell phone camera can record video footage of a police encounter, [body cameras] help police departments ensure that events are also captured from an officer’s perspective,” the report stated.

Video footage has played a key role in several episodes that have dominated headlines. A civilian recording recently showed Freddie Gray being dragged toward a Baltimore police van a week before he died of a severe spinal injury, setting off days of protests. And a bystander’s video showed a South Carolina officer firing multiple shots into the back of a fleeing driver last month; the officer was charged with murder after the video was released.

In the wake of the demonstrations in Ferguson and elsewhere, activists have pushed for wider adoption of body cameras, though experts caution that they raise issues involving privacy, when the officers can use them and who gets to see the footage.

There are also costs involved with outfitting officers with body cameras and storing all the data these devices will produce. Police in Phoenix said earlier this year that it would cost more than $3.5 million to outfit officers there with body cameras and store the footage.

The new pilot program, which will be announced Friday, will not provide federal funding for data storage, but it will help agencies that apply with training and technical assistance. Agencies are required to have their policies in place before they can buy cameras, according to federal authorities, but this new program will help them set up policies governing how the cameras can be used.

The Police Executive Research Forum (PERF) studied body cameras and determined that officers wearing them should have to activate the devices during most interactions with people and calls for service.

Police departments using these cameras say their presence “often improves the performance of officers as well as the conduct of the community members who are recorded,” according to a publication PERF released last year with the Justice Department’s Office of Community Oriented Policing.

But the cameras also evoke privacy concerns, it said, something that could crop up when officers are interviewing victims of rape or abuse.

Authorities in more than a dozen states have discussed limiting public access to the footage recorded by these cameras, while other places have decided to release the recordings in limited ways. In Seattle, where a dozen officers began testing these cameras in December, footage is posted to YouTube and blurred to protect identities. Clearer footage can be sought through a public-records request.

Sari Horwitz contributed to this report.

[This post has been updated.]