After decades of debate, and unknown numbers of lost lives, the board that controls the Golden Gate Bridge took a major step toward building a suicide barrier on Friday, voting to erect a net under the span.

The 14-to-1 vote came after several failed efforts over the years to support a physical barrier on the Golden Gate, where troubled souls have long leapt to their deaths.

The current plan still must pass a final environmental review, including a look at how a net might affect pelicans and cormorants, which frequent the bridge. It also needs financing: the estimated cost of the metal net is $40 million to $50 million.

Despite the uncertainty, supporters of the plan hailed the decision. “This is a red-letter day in the history of San Francisco,” said Dr. Mel Blaustein, the president of the Psychiatric Foundation of Northern California, which has lobbied for a barrier. “It’s a suicide magnet. And sometimes all they need is a certain amount of time to stop and reflect and change their mind.”

About two dozen people a year kill themselves at the bridge, where the roadway hovers more than 200 feet above San Francisco Bay and the railing stands only four feet high. Officials stopped publicizing the total number of suicides in the bridge’s history in order to discourage potential jumpers, but it is estimated that about 1,300 people have leapt to their deaths.

The net, made of wire rope coated with plastic, would hang about 20 feet below the walkways on either side of the bridge. It would also extend 20 feet out.

Denis Mulligan, chief engineer for the Golden Gate Bridge, Highway and Transportation District, which oversees the structure, said the net would partially collapse around anyone who jumped into it, allowing rescuers to fish the person out. But deterrence seemed more the point, he said, noting that the bridge staff already stops about two-thirds of those considering a leap.

Mr. Mulligan said such nets had been successful at several sites in Europe, including a cathedral in Bern, Switzerland.

For all the loss of life, the suicide barrier has not been universally embraced in San Francisco, where the bridge’s Art Deco-inspired beauty is a major tourist draw. The district conducted an online survey on the various options when it came to barriers, one of which was not to build one at all. Half of respondents chose “No Build.” Pending a financing plan and final approval, the board could begin soliciting bids by next year, said Mary Currie, a district spokeswoman.