Police officer JaShawn Colkley wears a body-worn camera mounted on glasses, during a news conference to announce Washington D.C. Metropolitan Police Department's (MPD) new body-worn cameras, at City Hall in Washington DC. (Michael Reynolds/EPA)

BEFORE TOO LONG, District police officers on patrol are likely to have miniature, body-worn video cameras as part of their standard gear, in addition to badge, gun, handcuffs and nightstick. That welcome and timely measure, announced Wednesday as a pilot program by Mayor Vincent C. Gray (D) and Police Chief Cathy L. Lanier, should go a long way to promoting better interactions between uniformed officers and civilians — and providing critical video evidence when things go wrong.

The price of equipping some 1,500 patrol and school officers with the cameras, which can be mounted on a collar, cap or even sunglasses, will be considerable; the devices can cost up to $700 each. But that’s a small price to pay, given the expected and potential benefits, which include a reduction in violent encounters as well as complaints against officers.

Police departments across the country, including those in New York City and Los Angeles, have started to test and deploy the little cameras. In many cases, including the District’s, the unions representing patrol officers have also welcomed the cameras in the belief that they will lead to better policing and a drop in the number of bogus complaints against officers.

Union President Delroy Burton, who represents D.C. police rank-and-file officers, cited the case study of the police department in Rialto, Calif., where the number of complaints filed against officers plummeted by almost 90 percent in the first year after the cameras were deployed — even though just half the officers were wearing them in each shift. Incidents involving the use of force by officers also fell sharply, the study found.

There are concerns about the rules governing the cameras and the evidence they collect. Among the key questions are when the cameras start and stop rolling; to what purposes the footage is used or not used; and how long it is retained in storage.

Those are legitimate questions; they are also possible to resolve in favor of constructive use of the cameras. In the District, Chief Lanier, in consultation with union officials, decided that officers will be required to start recording with a camera as soon as they receive a call for service; the camera will continue to roll until the call is finished. That should address the concern that the cameras could be used to troll for trivial administrative violations by officers or would violate their privacy.

It’s not hard to think of instances in which video evidence would do much to settle or shed light on bitter disputes about the use of force by police — think of the Michael Brown killing in Ferguson, Mo., this summer. And while some civil liberties groups have expressed concern about intrusive filming of citizens, that worry seems a little archaic. The truth is that anyone can be filmed in public at virtually any time, without their knowledge, given the proliferation of security and phone cameras. Their use by police is overdue.