Barrier transfer machine
（重定向自Zipper Machine）
![A barrier being moved on the Golden Gate Bridge](/Images/godic/202502/22/-Golden_Gate_Bridge_Moveable_Median_Barrier.webm3556.jpg")
![Linkage of moveable barriers[1]](/Images/godic/202502/22/Linkage_of_moveable_barriers3556.jpg")
![This large machine was used on the Auckland Harbour Bridge to shift the center lane back and forth to accommodate rush hour traffic.](/Images/godic/202502/22/Barrier_Transfer_Machine_on_the_Auckland_Harbour_Bridge3556.jpg")
Barrier transfer machines, also known as zipper machines or road zipper, are heavy vehicles used to transfer concrete lane dividers, which are used to relieve traffic congestion during rush hours.
The vehicle contains an S-shaped channel in its undercarriage which lifts the barrier segments (which may weigh over 1,000 pounds (454 kg)) off the road surface and transfers them over to the other side of the lane, reallocating traffic lanes to accommodate increased traffic for the currently dominant (peak) direction. These barriers are linked together with steel connectors to create a sturdy but flexible safety barrier.