BENICIA -- Despite safety and other concerns, a divided City Council early Wednesday narrowly approved the installation of three digital billboards along Interstate 680.

The large digital signs will flash ads every few seconds and help the city raise cash.

There are now six billboards in Benicia along Interstate 680. The city's sign ordinance prohibits new billboards but allows existing ones -- including the three in question -- to be replaced or modified.

The planning commission approved the digital billboard use permits Nov. 29, but three people appealed to the council -- including a commissioner who changed her mind after casting one of the deciding votes.

A divided council wrestled with issues of aesthetics, driver safety and whether the digital signs would lure shoppers away from Benicia.

Mayor Elizabeth Patterson and Councilman Tom Campbell opposed the digital signs, citing safety and economic concerns.

"I don't want to be responsible for someone plowing off the road looking at some stupid digital billboard," Campbell said.

They were outvoted by council members Mark Hughes, Alan Schwartzman and Christina Strawbridge, who said the billboards would generate revenue. Staff estimates indicate the city could receive as much as $500,000 a year. They also cited promises of advertising time on the signs for community events.

The Federal Highway Administration allowed digital signs for the first time in 2007. California is one of 39 states that allows them; Oakland is among the locations where they've been installed.

Research is ongoing as to how electronic signs affect highway safety. A recent Swedish National Road and Transport Research Institute study found that digital billboards hold the gaze of drivers longer than two seconds -- a threshold that previous studies have shown to be dangerous.

City officials recommended the billboard upgrades as part of negotiations with prospective sign operators Clear Channel Outdoor and CBS Outdoor. The signs are on city property, and if converted to digital technology could generate more revenue for the city.

Craig Andres, a Benicia business owner who lost the use of his legs in 1995 when a motorist collided with his bicycle in Mount Diablo State Park, appealed the billboards because he thinks they will distract drivers.

"Everywhere else in America where this debate is going on, people are trying to ban them," said Andres, who owns Insight Glass near the Nationwide Auction Systems sign designated for replacement on Park Road. The sign conversion could lower his property value, he added.

The council's rejection of two appeals of CBS Outdoor's permit to replace the billboard on Park Road was deemed invalid because the opportunity for rebuttal was omitted from the proceeding.