But with its myriad uses, departments are wrangling over several major policy considerations and their implications on privacy and officer liability.
-WHEN DO YOU TURN THEM ON/OFF?
The biggest question for departments is whether officers should be recording at all times. Should they turn them off when speaking to confidential informants or during sensitive victim interviews? What if the person doesn't want to be filmed? And how might it impact the prosecution?
Many departments tell officers to wear their cameras at all times but allow them some discretion on filming. But that could also create problems later, said Scott Greenwood, general counsel for the national American Civil Liberties Union and an expert on the devices.
"If officers are allowed to use the videos only when it's to their advantage, then there won't be public support for this, and most of the advantages to accountability and oversight will be lost," he said.
-CAN AN OFFICER WATCH THE TAPE?
Some departments allow officers to watch the tape before they write their reports; others require them to make a statement to internal investigators, if that's applicable, first.
"I'm going to acknowledge to you that a member's recollection actually changes after seeing the video," Oakland police union chief Barry Donelan said. "I've seen it."
Memory doesn't work the same as a video camera; it's impossible to go frame by frame and so what an officer saw and remembered out of a high-adrenaline situation may not match the tape, Donelan said.
It doesn't always mean they're lying, he said, sometimes it just means they're human.
-WHO GETS TO SEE AND WHO PAYS?
A key issue that's starting to arise is what happens when someone files a public records request for the video - is it considered a police report, an investigatory file?
Policies generally don't always address this and there haven't been enough requests.
Greenwood said the media and public should not have access to anything they wouldn't have the right to be physically present to observe. For example, a reporter wouldn't be present during a victim interview nor would they go in with police on a search warrant.
In Phoenix, the police union made a records request for all the footage from the initial 90-day camera trial and was told it would cost $11,000 because of the review process and to address privacy concerns, said Phoenix police Officer Joe Clure, who heads the union. They decided not to go for it.
-HOW LONG IS IT KEPT?
Some civil rights advocates recommend footage be retained for up to the statute of limitations on filing a complaint on an officer, which is usually a year in California.
If there's an ongoing case, or possibility the footage will be used in prosecution, then it should be flagged and kept until that's completed including any appeal. For basic daily interactions that don't produce investigatory material, video can be deleted between 30 and 90 days, Greenwood said.
Police in Rialto, Calif., keep videos in cases involving felonies for seven years; homicides for 100. Sgt. Richard Royce, the union chief, there's also a process for purging videos from the system in case something is accidentally recorded. The Los Angeles Police Department is currently keeping video for at least five years.