Merge like a zip

Summary

This pattern is for drivers, riders and cyclists approaching a lane closure or lane end in heavy traffic. It describes the zip merge: both lanes stay in use up to the merge point, then vehicles take turns, one from each lane.

Recommendation	Why?
In slow or queuing traffic, use both lanes up to the merge point.	Using both lanes shortens the queue and makes merging at the point where the lane ends predictable for everyone.
Take turns at the merge point, one vehicle from each lane.	It’s fair, it’s easy to understand and it keeps both lanes moving.
Indicate early.	Others can see what you plan to do and leave a gap.
Match the speed of the lane you’re joining.	Merging at a very different speed forces others to brake hard.
Leave a gap for the car in front of you to merge into.	One car’s worth of space keeps the zip working, and a three-second gap in flowing traffic makes it easy.
Don’t block the ending lane or speed up to close a gap.	It’s unsafe, it may be illegal, and it slows down the whole queue.
When traffic is flowing freely, merge early where it’s safe.	At speed, there’s more room to merge smoothly before the lane ends.
Check your local road rules.	Who gives way at a merge differs between countries and situations, and signs at a particular merge override general habits.

Context

This pattern suits roadworks, lane closures, on-ramps where a lane runs out and any place where two lanes become one in heavy traffic.

It does not suit merges controlled by signs, signals or lane markings that tell one lane to give way, or roads where local rules say otherwise. Follow the signs and markings first.

There’s a trade-off between perceived fairness and efficiency. Many drivers feel that going to the end of the lane is “queue jumping” and merge early. In slow traffic that leaves one lane empty and makes the queue longer. This pattern chooses the late, alternate merge in congestion, and an early, smooth merge when traffic is moving freely.

Usage

Approaching: watch for signs, indicate, and stay in your lane. Keep a steady gap rather than creeping up to the car ahead. If the merge is near your destination, knowing where you’ll park saves last-second lane changes, see Park before you arrive.

At the merge point: look for the driver you’ll follow, let one vehicle go ahead of you or move in after one, and keep the rhythm going. A wave of thanks helps.

If someone doesn’t take turns: let it go. Arguing at low speed only causes bumps. Your aim is to get through calmly, not to win.

References

Your national or state road rules and driver’s handbook explain who must give way at merges and lane ends where you drive.