Sheriffs are campaigning to pressure Google Inc. to turn off a feature on its Waze traffic software that warns drivers when police are nearby. They say one of the technology industry's most popular mobile apps could put officers' lives in danger from would-be police killers who can find where their targets are parked, reports the Associated Press.

Waze, which Google purchased for $966 million in 2013, is a combination of GPS navigation and social networking. Fifty million users in 200 countries turn to the free service for real-time traffic guidance and warnings about nearby congestion, car accidents, speed traps or traffic cameras, construction zones, potholes, stalled vehicles or unsafe weather conditions.

Waze users mark police presence on maps without much distinction other than "visible" or "hidden." Users see a police icon, but it's not immediately clear whether police are there for a speed trap, a sobriety check or a lunch break. The police generally are operating in public spaces.