Zipper Merges Reduce Congestion & Keep Traffic Moving Smoothly

Monday, May 17, 2021 at 4:04 PM

INDOT is asking motorists to merge late rather than early.

Zipper Merges

(Aurora, Ind.) – With construction season well underway, the Indiana Department of Transportation is reminding motorists how to utilize zipper merges in construction zones.

Earlier this year, INDOT announced plans to transition from merging early to merging late with more widespread use of zipper merges in work zones this construction season.

Zipper merges are used when a lane is closed ahead due to road construction or maintenance work. The zipper merge is designed to keep traffic moving by allowing drivers to use both lanes until reaching the merge point.

Once drivers reach the designated merge point, drivers take turns moving into the open lane, simulating a zipper. INDOT says drivers who wait to merge just before the lane ends are doing it the right way.

INDOT adds that most drivers tend to merge at first sight of a “lane closed ahead” sign, however many slow too quickly, which can lead to unexpected lane switches, serious crashes, and road rage.

Zipper merges provide several benefits to the traveling public including:

Reduces speed differences between two lanes
Reduces queue length by up to 40 percent
Reduces congestion and keeps traffic moving smoothly
Creates a sense of fairness and equity that all lanes are moving at the same rate
Brings order to the merging process

For more information, visit INDOT: Home.

Zipper Merge