Metro

Rotaries disappear in favor of roundabouts

Rotary at exit 40 off 95 shown from above by drone.
Aram Boghosian for The Boston Globe
Rotary at exit 40 off 95 shown from above by drone.

The traffic rotary, Massachusetts’ peculiar contribution to American traffic engineering, has long been a source of pride and frustration that fits, or perhaps defines, the region’s quickly-seize-every-open-inch style of driving.

But now, very slowly and quietly, the state of Massachusetts is engaged in a project to make them extinct.

You read that right. Massachusetts, the state with more rotaries than any other, is getting out of the car-weaving game.

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Instead, with some paint, some signs, and a bit of construction, we’re turning them into roundabouts.

Is there really a difference, you ask? Well, let’s look to the good people of Wakefield and Reading, who last year were among the latest to experience this conversion.

At Exit 40 off Interstate 95, there was a very large rotary on the border of the two towns. Then, one day, the rotary was . . . different.

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There were painted lanes. And new signs everywhere telling drivers which lane they had to be in, depending on their destination. And the entrances were different, redesigned to slow cars down and get them organized.

The free-for-all improvisation that was the hallmark of rotary driving was all gone. In its place was a forced choreography. In other words: rules.

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The reception to this new thing, this “roundabout” where once there had been a rotary, was mixed, to say the least.

“This is my theory about the rotary at Exit 40: The insane traffic flow we all now deal with was created by a highway worker with a paint brush in one hand and a pint of Crown Royal in the other,” seethed an editorial by Bob Holmes on Wakefield Patch, a website that covers news in the area. “Drop a handful of over-cooked spaghetti on your kitchen floor and that’s what I felt I was looking at.”

“Absolute foolishness!” a man named D.J. Genzler ranted in a Facebook video of him driving around the new roundabout that racked up 184,000 views. “You couldn’t leave well enough alone? Just like everything else the state of Mass touches — screwed up for no reason.”

Well, there is a reason for this move to retrofit rotaries with roundabout principles, according to MassDOT officials.

“Safety,” said Neil Boudreau, the state’s top traffic engineer. “These are proven safety countermeasures.”

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To understand the retrofit, you have to understand the rotary, which rose to prominence in the state in the 1950s, a bit of “Yankee ingenuity,” according to Boudreau, designed to handle traffic entering and exiting the new interstate highway system.

The state now has over 100 rotaries — far more, and at a far higher density, than any other state. But what worked in the 1950s does not work the same in the 21st century.

The lack of organization on a rotary was both its beauty — cars could move quickly through them if traffic was light, barely touching the brakes — and its chief problem, especially as traffic volumes swelled over the decades. And like Wiffle Ball and space-savers, everyone seemed to have their own set of rules about how it was supposed to work, along with certainty that everyone else was doing it wrong.

“The classic rotary is somewhat of an unorganized free-for-all,” said Jonathan Gulliver, the state’s acting highway administrator. “This opportunity to upgrade them with the principles of a roundabout will make them smoother and less likely to result in a collision.”

The key is doing away with that pseudo dance maneuver that rotaries require, in which cars kind of trade places as they get on and off.

“A rotary is all about weaving,” Boudreau said, “and the reason they are falling out of favor is that lack of definition. By bringing in roundabout principles, we get cars organized and put them in the correct lane. You should not have to change lanes anywhere in a roundabout.”

Rotaries have a high crash incidence, though it is mostly sideswiping and rear-ending, and are nowhere near as dangerous as traditional lighted intersections, which have the potential for head-on and T-bone collisions, said Andy Paul, a state highway design engineer.

Roundabouts are safer still, largely because they involve a “deflection” for entering cars, a bit of reconstruction that slows drivers down and forces them into lanes that correspond with the exit they’ll be taking.

Signs such as these at Exit 40 off of Interstate 95 in Reading are part of the plan.
Aram Boghosian for The Boston Globe
Signs such as these at Exit 40 off of Interstate 95 in Reading are part of the plan.

Engineers say the reconfiguration also makes it much safer for pedestrians and bicyclists to cross.

After roundabouts gained popularity in Florida and Nevada in the 1990s, a study found that converting a traditional signaled intersection to a roundabout led to a 90 percent reduction in fatalities, Paul said.

The conversion of rotaries to roundabouts in Massachusetts will happen slowly, depending on funding, crash data, and requests from municipalities.

Fifteen conversions have already been done, and rotaries in Ayer and Gardner are next on the agenda. Some rotaries may survive — including two north of Fresh Pond in Cambridge that are believed to handle, with debatable efficiency, more volume than any other circular intersections in the United States. But eventually, roundabouts will become the standard.

The cost of a redesign varies widely, based on the size of the intersection and the traffic needs. But converting a rotary to a roundabout is cheaper than ripping up an entire intersection and starting from scratch. And it’s much less costly than installing “flyovers” to solve rotary problems, as was done in 2006, to the tune of $60 million, for the famously over-congested and accident-prone rotary near the Sagamore Bridge to Cape Cod.

A similar flyover was being considered for a rotary in Agawam a few years ago, Boudreau said, because of congestion caused by drivers heading to the Six Flags amusement park. A flyover would have cost about $15 million. Instead, MassDOT converted the rotary to a roundabout for less than a million, and the flow has improved dramatically, Boudreau said.

But with each change, Boudreau said, comes the inevitable pushback. Over time, he said, as drivers get used to the new flows, those criticisms usually turn to compliments.

Bob Holmes, the Patch writer who accused the state of being drunk when it repainted the Wakefield rotary, says that his mind is unchanged more than a year later.

“I’ve gotten better at navigating it, but the problem is that now half the people are following the new lines, and half are not paying attention to the new lines and are still going through it the way they always have,” Holmes said. “I’d still like to find the person with the paintbrush.”

Whether loved or reviled, rotaries were kind of our thing.

Coming soon to a circle near you: lanes.

Billy Baker can be reached at billybaker@globe.com. Follow him on Twitter @billy_baker.