Product Code Database
A barrier transfer machine, also known as zipper machine or road zipper, is a type of heavy vehicle that is used to transfer concrete lane dividers, such as Jersey barrier, in order 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 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.
The minimum length for some barrier systems is . The length can vary based on application and the amount of barrier needed to effectively deflect an errant vehicle.Technical Report. Barrier Systems Inc. TB 990901 Rev-1. p.1-2. Circa 2000.
Some barrier systems have four rubber feet on the bottom of each segment “to increase the coefficient of friction between the barrier element and the road surface”. This helps the barrier resist vehicle impact and keeps the barrier from moving significantly if struck.
Barrier transfer machines can typically move their barrier segments anywhere between in one pass, usually at a speed between . Some models of the machine hold of barrier at a time as they are engaged in transferring. The machine can transfer within the regular traffic flow without hindering other vehicles:
Upon completing its pass, some barrier transfer machines can be moved across outside traffic lanes away from the area. However, other systems simply park in a median between their movable barrier and an affixed barrier to keep them from impeding traffic flow. A barrier transfer machine that operates outside of Honolulu has its own garage in the space between viaducts.
| Auckland Harbour Bridge | |
| Southeast Expressway HOV lanes | |
| Puerto Rico Highway 52 | |
| I-30 | |
| H-1 | |
| Quebec Autoroute 13 | |
| Original Tappan Zee Bridge and the western portion of the Long Island Expressway | |
| Walt Whitman, Commodore Barry, and Benjamin Franklin Bridges (Delaware River Port Authority) | |
| Route du littoral | |
| San Diego-Coronado Bridge and I-15 Express Lanes Coronado Bridge Readies for New Zipper after 18 Years Coronado Times July 31, 2011 | |
| Golden Gate Bridge | |
| Richmond, California | Richmond Bridge bike lane |
| Puerto Rico Highway 22 and Puerto Rico Highway 18 | |
| Victoria Road Unzip extra lanes on Victoria Rd Daily Telegraph December 18, 2010 | |
| Alex Fraser Bridge Alex Frazer Bridge is getting a zipper Delta Optimist September 15, 2019 | |
| Theodore Roosevelt Bridge |
Another variant of the machine uses two narrower machines running in tandem. This setup tends to be used in (also known as contraflow lanes) when the movable barrier is used to divide two directions of traffic—the narrower machines are less of an impediment to traffic in either direction.
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