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Moveable Median Barrier

Moveable Median Barrier

Over the weekend of January 10, 2015, the Golden Gate Bridge became safer for drivers when a Moveable Median Barrier (MMB) was installed on the Bridge. The barrier virtually eliminated the possibility of head-on collisions.

Up until 2015, opposing directions of traffic were separated by 19-inch tall by 4-inch wide yellow plastic tubes that were manually placed every 25 foot into sockets in the roadway. These plastic tubes separated the outbound lanes (northbound from San Francisco) from the inbound lanes (southbound into San Francisco) and were reconfigured several times a day to better balance traffic capacity and demand.

The MMB cost $30 million to design and install, with $20 million provided by state funds through the Metropolitan Transportation Commission. 

The District held a ribbon cutting ceremony on January 11, 2015, at Vista Point at the northern end of the Bridge in Marin County. 

Today, the MMB is moved by teams of two Bridge workers driving a “zipper” truck. The truck picks up the barrier on one end and offsets the barrier by about ten feet on the other end. The lane change operation typically takes about thirty minutes to complete.

The barrier is typically positioned to allow three lanes of traffic southbound and three lanes northbound on weekends and during the day on weekdays. During weekday commute periods, the barrier is shifted to four lanes southbound into San Francisco in the morning and to four lanes northbound during the evening commute.

Since the barrier was installed, there have been very few significant collisions into the barrier. 

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