In cities across the United States, government officials are installing sophisticated audio surveillance equipment on public buses, according to a report released on Monday.

Documents obtained by The Daily indicated that at least seven cities throughout the United States were installing surveillance systems capable of capturing riders' conversations in addition to the video already being captured by existing systems.

"This is very shocking," University of Pennsylvania privacy law expert Anita Allen told The Daily. "It’s a little beyond what we’re accustomed to. The adding of the audio seems more sensitive."

While transit agencies say that the system is intended to enhance saftey and resolve passenger complaints, experts have warned that the technology could easily be misused.

"Given the resolution claims, it would be trivial to couple this system to something like facial or auditory recognition systems to allow identification of travelers," security consultant Ashkan Soltani explained after reviewing the specifications of one system. "This technology is sadly indicative of a trend in increased surveillance by commercial and law enforcement entities, under the guise of improved safety."

For example, the system requested in Eugene, Oregon is expected to have five audio channels on each bus and be "capable of distilling clear conversations from the background noise of other voices, wind, traffic, windshields wipers and engines," The Daily reported.

Systems are also planned in San Francisco, California; Traverse City, Michigan; Columbus, Ohio; Hartford, Connecticut; Columbus, Ohio and Baltimore, Maryland.

"It’s one thing to post cops, it’s quite another to say we will have police officers in every seat next to you, listening to everything you say," Washington University School of Law professor Neil Richards explained, adding that the surveillance was like having "a policeman in every seat with a photographic memory who can spit back everything that was said."

(h/t: Wired)