Use the technology

The technology is used now by millions of Californians to pay bridge tolls automatically, access locked buildings and unlock their vehicle's ignition. Wal-Mart uses it to track inventory, and proponents see it as a future tool to prevent kidnapping.

Students at the new University of California, Merced, campus will begin classes this fall using cards containing the data-carrying tags for use in self-checkout of library books.

But civil libertarians and state Sen. Joe Simitian want government to think twice about using radio-frequency technology for public documents - such as driver's licenses - that vast numbers of Californians must carry.

They worry that personal information conveyed by the data-carrying chips, known as RFID, could violate privacy if stolen or used illicitly.

Simitian said he is wary of requiring Californians to "broadcast" their identities.

"Let's get ahead of this problem," said Simitian, D-Palo Alto, who has proposed Senate Bill 682 to set standards for use of such technology by public agencies.

"Once this technology proliferates into millions of government identity documents, it's going to be very hard to put the genie back into the bottle," he said.

SB 682 would ban for three years the use of radio-frequency tags on driver's licenses, public library cards, government health or benefit cards, and on student ID cards in kindergarten through high school.