Golden Gate median barrier at last

It only needed more than 20 years, plus 36 head-on collision fatalities since 1971. But now finally the Golden Gate Bridge, Highway and Transportation District is moving seriously toward installing a $25 million concrete median barrier that can be moved to facilitate the bridge’s daily reversals of traffic flow.

Necessary paperwork was finally approved for enabling the GGBHTD to obtain $20 million in regional and state funds distributed by the Metropolitan Transportation Commission, with the final $5 million for the project to come from bridge toll revenues. Environmental and engineering analyses will begin now, and the movable concrete barrier is to be operational in three years.

At this point, the bridge’s opposing north-south traffic flow is divided only by a barrier of thin air interspersed every 25 feet with yellow 19-inch-tall rubber tubes as a visual aid for the lane directions. Because San FranciscoMarin County traffic commute varies so greatly throughout the workweek, the tube line is moved to different bridge lanes as frequently as four times daily.

The new Quickchange concrete barrier will also be moved frequently by heavy-duty mobile scaffold/cranes called zipper trucks — because their action is something like the principle of a gigantic zipper. The median barrier is made up of interlocking jigsaw pieces somewhat resembling a milelong spinal column. The zipper truck takes in the spine near the front right wheel, picks it up about 6 inches and feeds it out near the rear left wheel. One engineering challenge that temporarily delayed the project was converting the system to handle a barrier only a foot wide, narrower than the standard Quickchange unit.

A slimmed-down barrier was necessary so as not to interfere with vehicle access in the middle lanes. Golden Gate Bridge lanes are only 10 feet wide — which is 2 feet thinner than normal highway lanes, due to the need to squeeze in a maximum number of lanes to accommodate moderntraffic loads on the 70-year-old bridge.

Of all the most dangerous deathtrap thoroughfares in San Francisco — 19th Avenue, Market Street, Doyle Drive — the iconic Golden Gate Bridge is by far the most famed and scenic. Yet the busy span has also carried 1.4 billion vehicles since 1971, when the count of 36 collision fatalities began. And the bridge’s accident rate is 0.64 per million miles traveled.

Citizens for a Safe Golden Gate Bridge, an advocacy group that has pressed for an effective suicide barrier and median divider since 1989, can hardly believe the time has finally come to put a true middle-lane barrier in place, after all the decades of false starts. “I’m still a little skeptical now,” Chairman Robert Guernsey said. “But if a barrier does go in place, it will be a tremendous safety asset.”

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