Legacy - Volume 3, Number 2 - (Page 18)

Tracker Trend Coming to America The modern roundabout gains ground in the United States A century ago, William Phelps Eno and Eugene Henard each created similar, yet competing, legacies; Frenchman Henard is responsible for Paris’ chaotic Etoile that encircles the Arc de Triomphe. >> The creation of New York’s Columbus Circle, seen here from above, marked the beginning of the modern roundabout. >> Eno designed New York City’s Columbus Circle—a “gyratory traffic circle,” moving drivers around a central island. While the Etoile is the stuff of legends—with stories of drivers unable to exit the circle and running out of fuel—the creation of Columbus Circle is considered the birth of the modern roundabout. What distinguishes Eno’s Columbus Circle as modern is the priority given to drivers already inside the roundabout. Incoming drivers must yield before entry; traffic does not stop for them. The result is a constant stream of vehicles moving through the roundabout. In contrast, vehicles traversing traffic circles must yield to entering vehicles—a functionality flaw that stops movement around the circle, eventually transforming it into a literal circle of frozen traffic. Now, sister companies DMJM Harris and CTE are building on Eno’s creation, tweaking its fundamentals to develop an even better roundabout. Just as the yield-before-entry concept revolutionized the roundabout, other recently18 Legacy—VOLUME 3: NUMBER 2, 2008 developed innovations—such as clearer signage, striping the approach, perfecting entry angles and lowering speeds—have further refined the modern roundabout package. While their famous predecessors are landmarks, today’s modern roundabouts are cropping up in the suburbs and along rural country roads. Their simplicity of design and operation, as well as their record of improving roadway safety, makes the choice easy for some road planners as roundabouts win over traditional intersection controls. And while roundabouts have been proven as a less costly alternative, they are also being considered as a valuable means of preventing incidents on the road. A 2001 study by the Insurance Institute for Highway Safety revealed that injury crash rates were reduced by 80 percent and all crashes by 40 percent on a survey of 23 U.S. intersections that converted from traffic signals or stop signs to modern roundabouts. “Roundabouts are becoming viable and desirable alternatives to all-way stop-controlled and signalized intersections because of their safety and operation benefits,” explains Jennifer Bixby, P DMJM Harris’s traffic engineering .E., department manager. Bixby and her Phoenix-based team completed a major design effort of roundabouts in Arizona’s majestic red rock community of Sedona in June 2007. On a 9-mile stretch of SR 179, nine singlelane and two multilane roundabouts are being built as part of a total roadway reconstruction project. Five are already complete and operational, and, Bixby notes, the public seems to approve. “We’ve seen greater public acceptance of roundabouts and foresee more cities, towns and communities implementing them,” adds Bixby. The initial roundabouts are within the Village of Oak Creek, a community south of Sedona serving as the entrance to “Red Rock Country,” and they present opportunities for DMJM Harris to showcase another trend and the benefit of roundabouts.

Table of Contents Feed for the Digital Edition of Legacy - Volume 3, Number 2

Legacy - Volume 3, Number 2 Contents In the Zone Gaining Altitude Six to Go: Planning Projects Promise Increased Mobility Women's Development Forum On the Move in the Southeast Protecting the World's Future Making the Grade Coming to America A Dedication to Development Looking to the Skies Spotlight on People and Projects An Aviation Innovation

Legacy - Volume 3, Number 2

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