A barrier transfer machine, also known as zipper machine or road zipper, is a heavy vehicle 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 (i.e. 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.