Zipper methodPoland
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169. Zipper method
The zipper method, also called zipper merging, is a way of merging traffic when one or more lanes end or become blocked. Drivers use the available lanes up to the merging point and then enter the continuing lane alternately, like the teeth of a zipper.
The method is especially useful in slow or congested traffic because it makes full use of the available road space and creates an orderly merging pattern. Drivers should avoid merging too early when zipper merging applies.
Wikimedia.org • Adrian Grycuk • CC BY-SA
How does the zipper method work?
Drivers remain in their respective lanes until close to the point where a lane ends or is blocked. Vehicles then merge alternately into the continuing lane, normally one vehicle from each traffic stream.
Why should drivers merge near the end of the lane?
Using the available lanes up to the merging point makes better use of the road space and can reduce the length of traffic queues. Merging too early leaves part of the ending lane unused.
Does zipper merging apply whenever two roads join?
No. Zipper merging generally applies in specific lane-reduction or obstruction situations. Normal priority and merging rules continue to apply where separate roads or entry lanes simply join unless national rules provide otherwise.

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