ADOT tests 'zipper merge' in Buckeye construction zone
An Arizona Department of Transportation (ADOT) project in the West Valley has been using a "zipper merge" to reduce delays when narrowing traffic to one lane.
The merge has been used during daytime hours on westbound Interstate 10 in Buckeye. A zipper merge works best for construction projects in areas of heavy traffic and slow speeds. Digital signs remind drivers to stay in both lanes until just before the lane restriction occurs. Then, drivers take turns merging from each lane, much like the way the teeth on a zipper close a zipper.
To be effective, drivers approaching such work zones must let go of the idea of merging early. For safety and efficiency, they also must resist the urge to straddle both lanes.
A zipper merge can reduce traffic backups by 40 percent, according to the Federal Highway Administration. It also makes driver behavior more predictable -- and enhances safety.
ADOT has used the zipper merge concept twice now and will evaluate results to see which future projects may benefit from its implementation.