Sources: Golden Gate Bridge, Highway & Transportation District, San Francisco; Lindsay Transportation Solutions, Rio Vista, Calif.; CP staff
A little concrete was added to one of the world’s signature steel structures over the second weekend of January, as Golden Gate Bridge engineers effected a major safety upgrade for northbound (Marin County) and southbound (San Francisco) drivers: Installation of a 13,330-ft. Barrier Systems median structure.
A division of Omaha-based Lindsay Corp., Lindsay Transportation Solutions has delivered Barrier Systems’ flagship Quickchange Moveable Concrete Barrier (QMCB) and companion Road Zipper transfer vehicles worldwide for flexible traffic lane management. In contrast to the legacy Jersey concrete barrier, with flush, tapered top, the precast QMCB has a T-shaped cap enabling Road Zipper lifting and lateral relay—mimicking a sidewinder.
A streamlined version developed for the Golden Gate Bridge, Highway & Transportation District combines a galvanized steel shell and concrete filling, 32-in. high, with 12-in. top width and 24-in. base, plus pin connector linking. Dubbed Moveable Median Barrier (MMB) and slightly narrower than the QMCB, it was specified after nearly two decades of engineering and review as the District sought a safe, robust solution to virtually eliminate crossover collisions between outbound (north) and inbound (south) drivers.
Prior to the MMB deployment, the agency used 19-in. tall, 4-in. plastic tubes, spaced at 25-ft. intervals—reconfiguring lanes throughout the day based on real-time traffic volumes. The District estimates a $30.3 million initial MMB investment, funded by primarily by the State of California through the Metropolitan Transportation Commission, plus bridge toll revenues and a minor federal contribution.