Construction
MUTCD W20-5
Lane Closed Ahead Sign — Meaning
- Category
- Construction
- Shape
- Diamond
- Colors
- Orange, Black
- Text
- (lane closure diagram)
- MUTCD Code
- W20-5
What does the Lane Closed Ahead Sign mean?
The Lane Closed Ahead sign is an orange diamond showing a multi-lane road with one lane marked as closed (X or arrows merging). It warns drivers that one or more lanes will be closed ahead and traffic must merge into open lanes.
-
1
Begin merging early but use the zipper merge in heavy traffic
-
2
Use turn signals well in advance
-
3
Match the speed of the lane you are merging into
-
4
Watch for orange cones, barrels, and barriers marking the closed lane
-
Approaching construction zones with lane closures -
After accidents that block a lane -
At maintenance work (repaving, sweeping, line painting) -
During temporary events affecting traffic
The "zipper merge" — alternating one car from each lane right at the merge point — is the most efficient way to merge in heavy traffic. Studies show it moves traffic 40% faster than early merging.
Should I merge as soon as I see the sign?
In light traffic, yes. In heavy traffic, use the zipper merge — continue in the closing lane until you reach the merge point and alternate with vehicles in the open lane. This moves traffic faster overall.
Why do some drivers refuse to let zipper-mergers in?
Cultural perception that "late mergers" are cheating. In reality, the zipper merge is the engineered, recommended technique used in most countries.
What if the closed lane reopens later?
Watch for "End Road Work" signs or for cones to be removed. Until you see clear indication, treat the lane as closed.
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