Glossary

The zipper principle

What Is the Zipper Principle?
The zipper principle, sometimes called the gear principle, is used in heavy traffic when two lanes merge into a single lane. The core idea is to alternate vehicles—one from the left lane, one from the right—just like the links of a zipper.

Why Use the Zipper Principle?

  • Reduce Congestion: By fully utilizing both lanes before merging, traffic flows more smoothly and avoids long lines in one lane.
  • Fair Distribution: Each vehicle contributes to a shared flow, minimizing frustration and bottlenecks.

How Does It Work in Practice?

  1. Continue in your lane until you must merge (avoiding an overly early or abrupt lane change).
  2. Alternate vehicles: One from the left, one from the right, and so on.
  3. Stay alert to nearby drivers and maintain a steady pace. Signaling or making eye contact can help coordination.

The goal of the zipper principle is to maintain smoother traffic flow and reduce the risk of congestion when lanes merge. By cooperating and taking turns, everyone benefits from a safer and more efficient driving experience.

Other words