Should cell phones be banned on city transportation?

Driving and talking on a cell phone has been banned in several states for obvious reasons, but does this mean you shouldn't talk on your cell phone if you take public transportation? It depends. Here in the Bay Area, the San Francisco Chronicle reports that the Golden Gate Transit bus system has certain restrictions on cell phone abuse.

In the article, a woman boarding a Golden Gate Transit bus in Marin County was told to turn her cell phone off over the loudspeaker. The woman was confused since there were no signs on the bus, but according to the transit agency's web site, cell phone use is permitted as long as you don't disturb your fellow passengers or the bus driver. Apparently, those around you can ask you to shut up or hang up if you're being too loud. The transit site even includes cell phone advice, such as putting your phone on vibrate or silent and screening your incoming calls, so you can send non-urgent calls to voicemail.

Unfortunately, this isn't the first time has happened—a similar incident occurred on a New Jersey bus line. Nobody wants to be bothered with other people's cell phone calls, especially in public spaces, but shouldn't passengers be at least warned? A sign would surely help.

Congress is pushing an in-flight ban on cell phones to "halt airplane noise," so could a cell phone ban on city buses be next? Should it be? What do you think?

Related:

Marin County: Cell phones on Golden Gate buses
U.S. moves closer to banning cell phones in flight

Europe Closer to Allowing Phones on Planes