The barrier is designed to provide a safer and more efficient system of separating opposing lanes of traffic, while allowing the number of lanes to be changed to suit tidal traffic flows. Transfer machines will be used to move the barrier several times a day.

The new system has been designed to reduce the potential for cross-over collisions and has been installed on the 2.7km bridge and on the approach stretch of the highway to the north.

More than 3,200 of the units are in place. They steel-clad units are approximately 300mm wide and 810mm high, filled with high-density concrete. They are connected in a line using steel pins to form a semi-rigid median barrier. Each barrier unit weighs about 680kg.