BART police are wearing small video cameras in a test project aimed at increasing transparency in the agency -- which has come under scrutiny for fatal shootings.

Police several weeks ago began testing six clip-on cameras. Officers switch on the cameras before all interactions with people in the field to create a permanent record, officials said.

"They are the next wave of technology in law enforcement," said Ben Fairnow, BART deputy police chief. "In the end, we're all human, and you can get two people who see the same event differently."

BART will test a manufacturer's loaner cameras before deciding whether to buy enough for all officers on patrol. Oakland police assign cameras to their officers.

BART has faced many protests this year over an officer's fatal shooting of Charles Hill, a knife-wielding homeless men, on July 3. A San Francisco train station camera recorded video of an officer whirling and firing the fatal shots, but the fixed camera failed to capture a view of Hill.

Another BART police fatal shooting became famous worldwide in 2009 when a train rider's cell phone recorded then officer Johannes Mehserle shooting in the back an unarmed passenger, Oscar Grant III. Mehserle was later convicted of involuntary manslaughter and served a two-year sentence.