The city officials in San Francisco, Baltimore, Columbus, Hartford and some smaller cities are reported to be pressing ahead with plans to install systems that will allow them to listen and record bus riders' private conversations in addition to the video footage already being recorded by existing devices, Voice of Russia reported.
They claim that audio surveillance will allow them to better ensure passenger safety, solve crimes and resolve complaints.
But civil liberties advocates are alarmed by the move. They say this is a possibility for police or other authorities to eavesdrop on conversations without warrants.
In San Francisco city transit officials recently signed up a $5.9 million contract to install audio monitoring devices on 357 buses and trolley cars over the next four years.