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Zipper Merge

​When a lane is closed for construction or when a two-lane road narrows to a single lane, motorists may be instructed to use a technique called a zipper merge. A zipper merge occurs when motorists use both lanes of traffic until reaching a defined merge area, and then take turns merging into the remaining open lane.

Vehicles in the merging lane must signal, and drivers in the through lane should each let one vehicle merge. This technique has proven to make the traffic flow more quickly and efficiently for drivers in both lanes.

Zipper Merge Benefits: 

  • Reduces differences in speeds between two lanes
  • Reduces the overall length of traffic backup 
  • Creates a sense of fairness that all lanes are moving at the same rate 


How is Zipper Merge different from a regular merge?
Typically when drivers see the first Lane Closed Ahead” sign in a work zone, they slow too quickly and move to the lane that will continue through the construction area. This driving behavior can lead to unexpected and dangerous lane switching, collisions and road rage.

To zipper merge, when you see the Lane Closed Ahead sign for your lane and traffic backing up, stay in your current lane up to the point of merge. Then take turns with other drivers to safely and smoothly ease into the remaining lane. Please be polite at the merge point - taking turns will get everyone to their destinations more quickly.