One hundred Boston police officers are now equipped with body cameras as they carry out their duties. That's after a judge's ruling Friday cleared the way for a delayed body camera pilot program — long pushed by local activists — to finally launch.

Here are 10 things to know about the pilot program:

1. What is it?

The program is a six-month pilot to test out body-worn cameras on Boston police officers. Dr. Anthony Braga, who heads the School of Criminology and Criminal Justice at Northeastern University, will analyze the effectiveness of the program by looking at police and community interactions, citizen complaints, use of force incidents and community satisfaction. Two companies — Taser and Vievu — have been contracted for the pilot. The city has allotted $500,000 for the program.

2. Who is participating in the pilot program?

After no officers volunteered, Braga selected 100 to participate in the pilot. The group is diverse and comes from five sections of the city and the department’s Youth Violence Strike Force. According to the department, 55 are white, 29 are black, 13 are Latino, and three are Asian. And 87 of the 100 officers are men.

Also, Police Commissioner William Evans announced last week that eight members of his command staff will wear body cameras for the duration of the pilot program. However, those commanders will not officially be part of the study group for the pilot program.

3. How will the body cameras be used?

According to the department's policy guidelines for the program, officers will only turn on the cameras while conducting official law enforcement duties. They will record all contact will civilians — such as during vehicle stops, when responding to a call, or while searching an individual. The cameras aren't to be deactivated "until the encounter has fully concluded and/or the officer leaves the scene." The policy gives officers discretion not to record in some instances where there’s a reasonable expectation of privacy — like locker rooms, hospitals or places of worship. And officers must get consent to record inside a person’s private residence if they don’t have a warrant, or during a non-emergency situation.

The policy also allows officers to view the body camera footage prior to writing police reports and in some cases before making a statement about an incident. That part of the policy has drawn criticism from activists and community members.

Read the full policy.

4. How do the body cameras actually work?

The cameras attach to the front of an officer's uniform and have an on/off switch. They begin recording when they are activated. Boston police will be using two types of body cameras, one from Taser and one from Vievu. Superintendent-In-Chief William Gross, one of the commanders who will wear a body camera, showed me his device at a recent peace walk in Roxbury. His model is from Taser and uses cloud storage while Vievu uses "an external storage device that's kept at the station," Gross said.

His body camera has an app to manage the footage. "It stores the video and you tag it and say what incident had just occurred and then it goes to the cloud," Gross said. "You can't alter it, you can't send it to YouTube, you can't touch it. It's all administrators [that] can only touch that."

-- Related: Here & Now: Taser On How Body Cams Work And Storage

5. Why is the city doing a body camera pilot program?

The point of the pilot is to see whether citywide implementation of body cameras would work in Boston. In the wake of several high-profile police shootings, body cameras have been part of a larger national conversation around police-community relations. Many see them as a part of 21st-century policing. In Boston, activists and community groups have been pushing for body cameras since 2014, following the fatal shooting of Michael Brown in Ferguson, Missouri. The technology has already become a reality for many police departments across the country. And in Massachusetts, several communities have been testing them out.

6. There's been a lot of talk about body cameras in Boston for a while. Why is the pilot just now getting off the ground?

There was a lot of back and forth between the city and the union, and the matter ended up in court. The Boston Police Patrolmen’s Association claimed the city violated an agreement to do a voluntary program by assigning body cameras to officers and filed an injunction seeking to halt the program. The city said it had the authority to assign cameras after no officers volunteered. A judge sided with the city in a ruling that gave the program the green light to move forward.

Before that, though, the pilot program had been in the works since last September. In April, there were plans to launch the pilot in July. That was delayed as the city and union negotiated. They reached a deal in mid-July. But by August no officers volunteered, so the police department assigned cameras. The plan was to start the pilot at the beginning of September. But, as explained above, the union took the matter to court.

7. Are there pilot programs in other cities?

Yes. Several cities across the country have pilot programs, including New York, Los Angeles and Chicago. And Los Angeles plans to make body cameras more widespread. (Here’s a report that looks at pilot programs in 50 cities.)

Police in New Orleans, Albuquerque and Rialto, California, are already fully equipped with body cameras. And cities like Minneapolis, Baltimore and Seattle are equipping their entire police force iteratively. In Massachusetts, several local communities, like Worcester, Leicester, Methuen and Gill, have tested out and in some cases fully implemented body cameras.

8. Will body cameras be fully implemented in Boston after the pilot program?

That’s unclear. A decision on whether to fully implement body cameras in Boston will be made at some point after the pilot program is complete. That will likely be "as soon as the research is done and Anthony Braga provides a report," Boston police spokesman Lt. Michael McCarthy said.

In an interview, Commissioner Evans said he'll make a recommendation and the department will have to work with the city and city council around a budget to move forward.

"I think the officers will want to move forward with it, but ultimately it will be my recommendation and the mayor’s on whether the whole department [gets body cameras] and whether we go in intervals putting it throughout the department," Evans said.

9. What will happen with all that video footage from the pilot program?

The video footage will be stored two ways — through cloud-based storage and by the two companies (Taser and Veivu) the city has contracted to do the pilot program — according to police spokeswoman Myeshia Henderson.

10. What does the research say about body cameras?

There's still much to learn about body cameras.

Some studies have found body cameras significantly reduce the number of complaints against police and incidents of police use of force. For example, a 2014 U.S. Department of Justice report cited two studies. One found the Rialto, California, police department had a 60 percent reduction in officers using force and an 88 percent reduction in complaints against police. The other found 75 percent fewer use of force complaints against police in Mesa, Arizona. A study of Orlando police had similar findings.

Other studies have looked at the limitations of body cameras, noting murky policies and inconsistencies in how body cameras are used.

In Boston, the police department often emphasizes community policing, saying it has strong community relations. There has been some concern raised about how the body cameras may change how the public interacts with police (e.g., people not wanting to speak to police because of the body cameras).

During the court hearing over the Boston pilot program, the police union suggested cameras may cause people to react negatively toward officers. The union cited a study by the Rand Corporation that found some officers faced increased risk of assault while wearing cameras. The report notes other possible reasons for that result and says "much more work is needed to unpick the reasons behind these surprising findings." Evans — and, ultimately, the judge — expressed skepticism about the results of the Rand report.