Despite privacy advocates' concerns that they may be violating wiretapping laws, several cities have recently taken steps closer to becoming Big Brother. San Francisco, Baltimore, Columbus, Ohio; Hartford, Conn.; Eugene, Ore.; Athens, Ga.; and Traverse City, Mich., have installed or are in the process of installing audio surveillance systems on public buses, reports The Daily. The purpose, public officials say, is to increase passenger safety and resolve passenger complaints. Some of the installations -- like the $5.9 million one on 357 buses and trolleys in San Francisco -- are being paid for with grants from the U.S. Department of Homeland Security, according to the paper. The systems typically pair up audio conversations with camera images to produce synchronous recordings, which can be monitored in real-time and are also stored on the individual buses for 30 days to allow for later retrieval.