Barrier transfer machine

A barrier transfer machine, also known as zipper machine or road zipper, is a type heavy vehicle that is used to transfer concrete lane dividers, such as jersey barriers, which are used to relieve traffic congestion during rush hours. Many other cities use them temporarily during construction work. The lanes created by the machine are sometimes referred to as "zipper lanes".

One advantage of barrier systems over other lane management treatments such as traffic cones or overhead directional lights is that a solid, positive barrier prevents vehicle collisions due to motorists crossing over into opposing traffic flow. A disadvantage is that lane widths can be slightly reduced.

History

The Road Zipper variant has been in existence since 1984–1985. Auckland Harbour Bridge had its original moveable barrier system installed in 1990. The Hawaii Department of Transportation debuted a zipper Lane on Oahu on August 18, 1998. The Benjamin Franklin Bridge has had a permanent barrier transfer system since 2000, when it was installed by the Delaware River Port Authority. A movable barrier system was introduced in Sydney, NSW, Australia, in 2012. The Golden Gate Bridge had a permanent movable barrier system installed in January 2015.

Operation

The vehicle contains an S-shaped, inverted conveyor channel in its undercarriage which lifts the barrier segments (which may weigh over ) 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) di