Body cameras worn by police will get a test run in parts of Bucks County starting Wednesday, ahead of a planned roll-out for several more law enforcement agencies in the fall.

Ultimately, they will join agencies across the country that have begun using body cameras, a trend spurred, in part, by growing attention to police shootings, primarily of black men.

Video footage, in both cases taken by witnesses, helped bring national attention to the deaths of Alton Sterling in Louisiana and Philando Castile in Minnesota earlier this month, sparking protests and outrage.

The boroughs of Chalfont and Doylestown and New Britain and Warminster Townships will participate in the pilot program starting next week. After a 90-day trial phase, during which departments will evaluate the use of the body cameras and make any adjustments, the Bucks County Sheriff's Department and police in Lower Southampton, Northampton, Plumstead and Warrington Townships would join the program.

Police officers now wearing body cameras include those in Philadelphia, Camden, and Chester City.

The funding is being provided by the U.S. Justice Department, which gave $23 million to 73 law enforcement agencies nationwide, including grants to Pittsburgh, Allentown, Carlisle, and Johnstown.