Some pretentious folks at the modern theoretical end of actual architectural and engineering construction like to deploy the lofty phrase "the built environment" as they evaluate the results of real practitioners' design efforts.
At the classical theoretical end, the ancient Roman engineer and architect Vitruvius was more straight forward. The work, he wrote, must have three qualities: firmness (no Kansas City hotel sky-walk collapses); commodity (no multi hundreds-of-dollars-per-square-foot donor named collegiate extravagances), and delight (no Frank Gehry randomly distorted crushed-tin-can appearances).
Neither Vitruvius nor the modernists theorized about the role of user behavior, although it was the basis of Coliseum design then and Yankee Stadium now, just as roadusers were design factors in both civilizations-then and now.
Consider the Roman-road speed bump: typically misidentified as pedestrian crossing blocks on such arteries as the Appian Way. It's hard to believe that they were so closely-spaced and built nearly a foot above the traveled way because of road-mud or trash depth, and easier to believe that their height and close spacing were engineered to cause proto-NASCAR charioteers to reduce speed and steer carefully for the narrow gaps to prevent embarrassing and expensive wheel destruction.
Getting mobs of pedestrians into and out of a venue is a problem different from getting individual vehicle drivers to their destinations without killing each other or wrecking their mechanized (or not) chariots, but it shares the necessity of guessing how courteously (or not) their human design-users will behave toward each other. That's a tougher guess in highway design than in stadium design; the latter hasn't changed much in two millennia; in the former, designers still don't know and can't reliably predict how members of the modern civilization will conduct themselves.
When John Keats wrote "The Insolent Chariots" in 1958, his complaint wasn't entirely that highways were paving over too much grassland; it was also that motorized-chariot drivers weren't nice to each other. Starting in the '20s and '30s, when motorized vehicle were replacing horse-drawn ones on a large scale, highway designers couldn't predict and design for driver behavior as well as Roman stadium designers could, for pedestrian behavior. Their abilities in the soft-science end of highway design haven't improved since, while their skills at the hard-science engineering end have.
Today, epoxy-clad reinforcing steel doesn't rust and self-destruct in the bridge concrete, but some drivers still assault each other at the lane merge and at the traffic circle, places where, more than the straight and open road, designers must assume some modicum of predictable inter-driver manners. It isn't always there.
Highway engineers have done better when designing around driver-self-interest instinct, which explains why, while Keats was writing his anti-auto polemic, the site planners of the New Seabury residential development on Cape Cod deliberately flouted standard practice and made the roads narrow, curvy, and bumpy: to keep speeds down. Today it's called the design-speed principle, and it's based on the fairly reliable fact that drivers won't do 70 where they can't see stopping distance ahead. In contrast, standard practice (on the Interstates, for example), calls for design speeds well in excess of 100 and government then hires ticket-issuers to profit from punishing the designed-for behavior.
Highway designers used to be more sanguine about driver manners than they are today: thus, when I first saw a state-of-the-art auto road built in the '20's on the Eastern Shore of Maryland, I understood that the design intent for the paved concrete center lane, flanked on each side by a gravel lane, was that drivers would courteously move off the higher-speed surface when they saw a car coming. It proved to be overly optimistic. Thirty years later, in Massachusetts, the gravel lanes were concretized, but it still didn't work: the center lane then was called "the suicide lane".
Today, some of the Interstate on-ramps display "yield" signage and some don't, and in some parts of the Heartland right-lane drivers move over, signage or not, to accommodate entrants, while coastal-State and urban drivers mostly don't. (Historical note: in 1913 Wisconsin adopted a yield-to-right rule, giving legal priority to the on-ramp charioteers. It hasn't survived.)
The traffic circle has survived in Mark Twain fashion (reports of its death have been greatly exaggerated) and in its modern incarnations is labeled variously as rotary (larger central circle) or roundabout (smaller central circle).
Rotaries were part of a highway subcourse in urban planning when I was in the halls-of-ivy classroom. We were instructed that the gyratoire was a brilliant French engineering innovation in the early 20th century. Why, it functioned perfectly around the Place de l'Etoile-the Arc de Triomphe site in Paris-and was in mid-century disfavor in the U.S. only because Anglo-Saxon drivers were inherently less civilized than their Gallic betters.
As you can now see in a simple web search, the then-unchallengeable academic Francophilia doctrine was-shall we say-misinformed. The first traffic circle, of roundabout dimensions, actually preceded the French rotary by three years when it was built by Americans in New York City's Columbus Circle (get it?) in 1904. It's still there.
Apparently, the original French word isn't a la mode any more; the preferred new one is rond-point.
As for the modern gyratoire in les montagnes verdes, its first design attempt, some five years ago on Shelburne Street in downtown Burlington, has suffered a post-conception pre-birth (temporary?) abortion.
The second, now in downtown Middlebury, has apparently survived the choice process which terminated its sibling; it will soon be on the ground north of the new Cross Street Bridge. How well will this rotary perform?
Well, that depends on the inherent courtesy/civilization level of its users. Given that Middlebury is more Europhile in general and Francophile, in particular, than your quintessential old-Vermont town of East Overshoe-and that the local drivers can therefore be expected by the highway designers to be more understandably and predictably courteous to each others and to visitors than mere ordinary Americans-its performance should please its designers, taxpayers, and charioteers.
As the French say: "Alors, mes amis, nous verrons ce que nous verrons."
Former Vermonter Martin Harris lives in Tennessee.