Commentary: Use the ‘zipper merge’ technique to make trips smoother

Ken Grant

Highway construction and maintenance season is still in high gear in Delaware. The beehive of activity in construction zones will continue well into autumn and beyond.

Asphalt now covers more than 94 percent of paved roads in the United States. It is estimated there are at least 30 thousand paving projects taking place on interstates, freeways, and multi-lane roadways in urban and rural areas across the country each day.

If everyone cooperates, a simple yet counterintuitive merging maneuver, christened the “zipper merge,” promises to untangle traffic jams, defuse road rage, and improve safety in work zones and heavy traffic. If everyone uses the zipper merge method, it could reduce delays in work zones by up to 40 percent, studies show.

Work zones contribute to as little as 10 percent, to as much as nearly a quarter, of all non-recurring traffic delays in the area. Dangerous lane switching and other bad driving behaviors in work zones could cause even more congestion and back-ups, and trigger crashes, officials warn. Instead of switching lanes as quickly as they spot the first dynamic message sign indicating lane closures ahead in a work zone, area motorists are urged to use the “zipper merge” technique in roadway construction zones. To do otherwise only invites travel delays, traffic congestion and frustrations, and reduces safety in work zones.

“Using the ‘zipper merge’ technique when it is safe to do so in construction zones will keep traffic moving, and help reduce crashes and congestion,” explained Kurt E. Gray, Director of Driver Training, AAA Mid-Atlantic. “When it comes to merging in heavy traffic conditions, most drivers do it wrong by merging too early. Study after study shows the ‘zipper merge’ is the safest and most efficient way to merge in work zones and heavy traffic. To do so, use all lanes fully until you reach the end of the lane, then alternate into the open lane. It does take some cooperation, but it maximizes road space and helps keep things moving.”

Some skeptics say good luck trying to teach longtime drivers new tricks. That is to say, convincing motorists to change their deep-dyed habits of merging early. The overarching goal of the “dynamic lane change” or the “late merge” technique is improving traffic flow and enhancing traffic safety in work zones and heavy traffic.

“The Delaware State Police supports our fellow agencies and recognizes their continued efforts with highway construction and maintenance in Delaware. A merging maneuver that can enhance traffic flow while improving safety in work zones can help travelers avoid traffic delays. We thank Delaware motorists for their patience and understanding especially in work zones,” said Sergeant Richard Bratz, spokesperson for the Delaware State Police

Zipper merging “can reduce delays by up to 40 percent in heavily congested areas,” according to studies conducted by the Colorado Department of Transportation. In addition to enhancing work zone safety, the “zipper merge” method, which derives its name from “teeth in a zipper,” also promises to “ease traffic and make driving through work zones go quicker.”

Drivers using the “zipper merge” method should continue to occupy all lanes until they reach the “taper point” in the work zone, and then take turns merging into the open lane in an orderly and alternating fashion. However, if there is no bottleneck and an early merge makes sense, feel free to do so. Drive consistently. Don’t rush ahead, only to slam on your brakes later.

Ironically, it gives a new meaning to the idiom “traffic cutter,” because, if properly used by drivers, the dynamic lane merge concept “will help mitigate traffic while reducing the chances of road rage,” according to researchers at the Texas A&M Transportation Institute (TTI). By force of habit, many drivers immediately jump into the other lane after seeing orange cones in work zones. It only makes traffic worse and heavier, studies by the Virginia Transportation Research Council show. Merging early or “cutting in line” in heavy traffic and work zones can also result in “unexpected and dangerous lane switches, serious crashes and road rage,” warns AAA. Here are some tips for merging in work zones.

• Slow down and obey the speed limit. Speed was a contributing factor in 29 percent of work zone deaths in 2017.

• Pay attention. Conditions could change quickly. Plus, 25 percent of fatal work zone crashes are rear-end crashes.

• Give heavy vehicles and equipment a wide berth and room to adjust to conditions.

• Move over, if possible, for workers.

• When ready to move over, signal your intent and use the zipper merge approach in an alternating fashion.

• If, however, a lane closure is due to a crash or breakdown, reduce your speed and move over as soon as possible to avoid endangering emergency workers and/or tow truck operators.

• Drop it, the phone, that is, and drive.

“The Big Time Roadwork” and road paving season typically begins in early May and concludes by October. This explains, in part, why most fatalities in work zones occur “during the months of May to September,” law enforcement and transportation officials and AAA Mid-Atlantic caution. Nationwide, “around 10 percent of highway congestion results from delays in work zones, leading to an estimated annual loss of $700 million in fuel costs alone,” warns the Federal Highway Administration (FHWA).

Ken Grant is AAA Mid-Atlantic’s Manager of Public and Government Affairs.

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