George Orwell warned about Big Brother, but some who glide through Bay Area toll booths to the “beepbeep” of FasTrak risk an even more haunting specter: Big Angry Soon-to-be-Ex Spouse.

As the number of cash-free bridge commuters rises, so do the ranks of divorce lawyers and other civil attorneys who have subpoenaed, and received, personal driving records from the agency that oversees the regional e-toll system.

Subpoenas that MediaNews obtained under the state Public Records Act turned up several cases over the last two years in which the Metropolitan Transportation Commission released FasTrak subscriber records in civil disputes.

The records include logs of the date, exact time and bridge where a car using FasTrak rolls through a toll plaza at any of the eight Bay Area spans.

“Part of the reason Fred has not had success . . . is that he takes too much time off,” claimed a woman who sought her husband’s toll activity in one divorce case. “His transponder records . . . will show how little he works.”

The use of FasTrak customer data in such cases reveals another wrinkle to what privacy advocates call a troubling question: At what cost life in the fast lane? Such concerns have largely focused on possible government monitoring. But other logical uses have long been foreseen.

The numbers remain small – fewer than 20 search warrants and subpoenas for FasTrak data in two years, most of them for criminal cases. Police and prosecutors say the records have helped catch criminals and bolster prosecutions.

Privacy advocates wonder, however, whether customers know that the records can also be used in civil matters, and they fear an increase as the e-toll system grows. About 620,000 people now hold FasTrak accounts, up roughly 65 percent from a year ago, officials said.

“You just kind of wonder if people would as happily use this system if there was a big red thing on the transponder saying, ‘All data collected by this device could be used in any court for anything,’ ” said Lauren Weinstein, founder of the Privacy Forum.

Along with credit card numbers for refueling FasTrak accounts and license plate numbers, the system logs bridge activity so drivers can dispute charges or violation notices, said Rod McMillan, MTC’s director of bridge operations and oversight. He said the agency keeps the data indefinitely.

“We’ve had cases where people come back a year or more after and say, ‘This is a wrong charge,’ ” he said.

Weinstein said the agency should purge old data or give customers an option to have their logs periodically deleted in exchange for waiving the right to appeal an old charge.

“It doesn’t make sense to say we’re holding onto the data for, say, five years so people could get their five dollars back,” he said.

McMillan said Monday that the agency is now planning to form a policy on how long to keep the data.

The system also is used to monitor traffic flow on most freeways, with roadside signals that read the windshield devices as drivers cruise past. Officials say that data is scrambled to allow anonymity. None of the lawyers interviewed by the Times said they received any of that data.

Tribune sister paper Contra Costa Times requested all subpoenas and search warrants of FasTrak records since June, 2005, when oversight shifted from Caltrans to MTC.

The system launched on the Carquinez Bridge in 1997 and reached all eight toll bridges in 2000.

Some lawyers said they have subpoenaed FasTrak records for years.

“We often have arguments about whether or not one spouse works to his or her maximum earning capacity,” said Alexandra Mussallem, a San Rafael divorce lawyer who said she has twice sought FasTrak logs. “If someone hits the Bay Bridge toll plaza at noon on a day he said he was working, you know he’s not working. He might be with his girlfriend in Contra Costa County.”

Another divorce lawyer jokingly pleaded with a Times reporter not to write this story, saying it could “ruin a great gig I’ve got going.

“With the FasTrak data and maybe credit card receipts, you can put together anybody’s life every day,” said Oakland attorney Matthew Graham. “It’s pretty damaging stuff you can come up with.”

He said FasTrak data recently helped him refute claims by a client’s wife that she worked often from home – an issue in a dispute over visitation rights. Graham said he has considered giving up his own FasTrak account.

Since the start, transportation officials have sought to ease privacy concerns, highlighting a policy that bars release of customer data “except as required by law or ordered by a court of competent jurisdiction.” McMillan said the policy is among the tightest of any e-toll system.

Neither the privacy policy nor the customer license agreement explains that court orders may include subpoenas in civil cases, which do not require a judge’s approval unless they are contested.

In one case, a judge agreed to quash a subpoena for Fas- Trak records.

The case involves a 70-year-old San Francisco man who is suing a business that fired him after three decades. He claims he worked hard.

The company sought to prove he didn’t. Sonya Smallets, a San Francisco attorney, argued that releasing FasTrak data “would be an unwarranted, Orwellian invasion” of her client’s privacy.

“When people get a FasTrak account they’re expecting to pay to go across the bridge,” she said in an interview. “They’re not expecting somebody’s going to be tracking every single one of their movements and creating a record that would be available to the public.”

Earlier attempts to create an anonymous e-toll system, in which drivers could buy value cards to use with their transponders, went largely ignored by toll authorities, said Phil Agre, a UCLA information studies professor and author of “Technology and Privacy: The New Landscape.”

McMillan noted that people with concerns have another option: pay cash. There is also a third way, he said. Drivers can open an anonymous account with no name or address and pay with cash at FasTrak’s service center. Only a few people have done it, he said.

That doesn’t surprise Weinstein, the privacy advocate.

“If people don’t know about it, it doesn’t help,” he said.

Most don’t, including a FasTrak customer service agent who answered a call on Monday from a Times reporter inquiring about an anonymous account. The agent said there was no such thing; every account needs a name.

“That’s how the system works,” he said. “You can pay your own toll. That’s as anonymous as it’s going to get.”