Car Merging Psychology: Don't Hate the "Sidezoomer"

How and When To Merge — Without Losing Your Cool

Every morning I face a decision that twists my stomach in a knot. On my route to work a sign announces that I need to merge into the right lane to take another freeway. The merging point is nearly a mile away but I feel a deep desire to get into the right lane as quickly as possible — even though it is barely moving.

Once I'm in the right lane, I stew as cars shoot past and then swoop into my lane at the last second. I did the right thing, I think. I waited my turn. The way other drivers are behaving isn't fair.

This little drama takes me back to elementary school. Lining up at lunch or waiting to use the monkey bars, there were always the kids who barged in line ahead of you, then challenged you to do something about it. I feel all those old emotions roaring through my system.

Why Late Merging Ticks Us Off
Merging is only one of a long list of driving situations that stir deep emotions. Yet, when best-selling author Tom Vanderbilt began his 400-page book Traffic: Why We Drive the Way We Do (And What It Says About Us), he zeroed in on merging as a universal measure of a driver's personality. The prologue of his book is titled "Why I Became a Late Merger (and Why You Should, Too)."

Vanderbilt suggests that a driver's merging style reveals his personality. There's an old cliché in driving studies," he says: "'A man drives as he lives.'" New York Times columnist Cynthia Gorney boiled the debate down to two main driving personalities: "lineuppers," who take their turn, and "sidezoomers," who race to the head of the line and dart into an opening at the last second. This is maddening to the well-behaved lineuppers. In fact, a Minnesota Department of Transportation study revealed that 15 percent of drivers actually admitted to straddling lanes to block late mergers in construction zones.

Gorney finds her description of sidezoomers gets a spirited response from everyone she questions. "When I raised [this] with my father, who is 83, he startled me by suggesting a longer label that included more bad words than I believe I have ever heard him use at one time." She even found a University of Washington engineer who had his own name for the two main merging personality types: cheaters and vigilantes.

Leon James, a.k.a. "Dr. Driving," whose Web site has a string of articles under the heading "The Great Merging Debate," says merging areas are especially challenging because there are basically two styles of merging that are often incompatible. When early mergers see the late mergers zip by, "most drivers feel irritated, some angry and roadrageous," he says. Trying to block them is "dangerous, illegal and begging for a confrontation."

James sees a connection between the different merging styles and a driver's personality. "Motorists who are less aggressive and more accommodating tend to be early mergers," James says. "They are more community-spirited drivers." On the other hand, late mergers are "more aggressive and opportunistic." And they don't necessarily think of themselves as an exclusive club, either.

"They feel that everybody can be a late merger, and if they choose not to be, it's their choice," James says.

The Case for Late Merging
When you apply the term "sidezooming" to late merging, it conjures up all kinds of negative images. But there is an argument for late merging: It's a more efficient use of the road.

Highway lanes offer a limited amount of space and, because of the volume of traffic, that space is becoming increasingly restricted. So the question becomes this: How can the maximum number of cars quickly move through a set space as that space narrows? Traffic engineers sometimes equate this situation to grains of rice flowing through a funnel. The analogy breaks down, however, when you realize that the grains are touching and sliding against each other as they move — we obviously don't want that with cars. But the comparison is still relevant.

High accident rates in construction zones triggered the Minnesota merger study, says William Servatius, construction programs coordinator in the Minnesota Department of Transportation's Office of Construction. He adds that when drivers are instructed to merge at construction areas: "Many times crashes occur due to aggressive driving, abrupt lane changes or sudden stops."

Using speed-sensing devices that display different messages depending on the speed of traffic, Minnesota DOT engineers developed what they call a "zipper," which meshes cars quickly. Signs advise drivers of the upcoming lane closure, tell them to use both lanes up to a point and then direct them to take turns merging. When traffic is flowing, drivers merge early to avoid unsafe maneuvers. But when traffic is congested, motorists make full use of both lanes. The data revealed that the change reduced traffic lines by 35 percent and also brought down "lane changing conflicts," says Craig Mittelstadt, Minnesota DOT's work zone safety specialist.

But most highways' merging zones don't display friendly signs that tell drivers it's OK to merge late. And so the conflicts continue. And along with the conflicts comes the inevitable finger-pointing (or finger-giving, in many cases).

Kinder, Gentler Merging
The morning after reading these merging studies, I decided to create a third category of driver for myself. I would be neither a lineupper nor a sidezoomer. Instead, I would be a "sidesignaler," politely cruising along by about a quarter-mile of stopped traffic with my turn signal on, requesting an opening. Sure enough, I reached the zipper and saw a gap between cars. In fact, it was a huge gap. I slid into the opening and held my breath. No blaring horns, flashing lights or angry shouts followed my maneuver. I risked a look in the rearview mirror and saw why. The driver was on a cell phone.

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