Four months after a controversial decision to temporarily shut down cellphone service in four public transit stations in anticipation of disruptive protests, Bay Area Rapid Transit officials say they can now interrupt service only under "extraordinary circumstances."

The new policy (.pdf), adopted unanimously Dec. 1 by the BART board, says examples of extraordinary circumstances include evidence that cellphones might be used to set off explosives, to facilitate criminal activity, in hostage situations or "to facilitate specific plans or attempts to destroy District property or substantially disrupt public transit services."

It was precisely a fear that protestors planned to disrupt public transit services, however, that led BART to shut down service for 3 hours in downtown San Francisco public transit stations on Aug. 11.

BART board president Bob Franklin told the San Francisco Chronicle that BART would not turn off service if faced with that situation again. "We would arrest people," he said.

The new policy, the Chronicle says, was developed in consultation with the Federal Communications Commission. FCC Chairman Julius Genachowski in a Dec. 1 statement called the policy "an important step in responding to legitimate concerns" and added that the agency will develop guidance of its own.

Execution of the shutdown, according to emails (.pdf) obtained by cybersecurity researchers from Indiana University's Center for Applied Cybersecurity Research through the California Public Records Act appears to have been initiated via a single email from a BART employee to ForzaTelecom, the Walnut Creek, Calif.-based BART cellphone service contractor.

"Gentlemen, The BART police require the M-Line wireless from the Trans Bay Tube Portal to the Balboa Park Station, to be shut down today between 4 p.m. & 8 Steve, please help to notify all carriers," wrote BART employee Dirk Peters at 8:45 on the morning of Aug. 11.

For more:
- download the new BART policy (.pdf)

Related Articles:
BART cellphone shutdown sparks FCC petition 
BART in cellphone shutdown imbroglio