Wednesday, September 19, 2012



The Burlington (VT) Free Press on Sunday ran a feature on accident and operational issues for the Winooski City Center roundabout with its five year history which includes several injury crashes and peak hour backup.  

This roundabout can be termed a hybrid, mostly roundabout in concept but dealing with a large oval size, two small parking areas served, seven overall streets and a huge central island park accessed by walker traffic lights at the middle of the oval, and acting as the primary feature of a city center with several buildings dating to the late 1800s.  The mostly two-lane   400 feet by 250 feet roundabout compares to current roundabout design practice for a two laner in urban practice of 150 feet diameter which serves walkers.  Finally, there is the added context, north to south, of a descending grade which makes speeds along the long 450 ft west side of the roundabout presenting a conflict for walkers at the southwest exit.  The comments below were submitted at the Free Press site:

Considering the seven intersecting streets, access to parking areas, and a central island park with a signal for walker entry--the Winooski City Center roundabout crash record may well be comparable with that of the three traffic signal intersections along with other signed connection this new “hybrid” roundabout replaced. The re-design of a roundabout impacts both congestion and safety—the Winooski study separating the two errs. Injury accidents really the test of safety—not lumping in non-injury crashes which relatively cost little. Federal Highway Administration employs $126,000 for the value of an injury, $6.1 million for a fatality—fender benders a few thousand dollars. For example, during the first five years of the Brattleboro Keene Turn roundabout injuries dropped 98% from 55 in the previous five years to one in the first five years of roundabout operation—but crashes went up significantly from roundabout design defects the Vermont Agency of Transportation (VAOT) continues to ignore to this day.

The complex nature of the issues in the Winooski case—both safety and congestion—require the attention of experienced practitioners in the field and no such practitioners exist in Vermont with perhaps a dozen available in the U. S., including designers of New Hampshire and Vermont roundabouts . Probably Michael Wallwork of Florida who designed the first Vermont roundabout is most knowledgeable on safety issues (particularly for walkers and bicyclists) and Barry Crown of the U.K. who designed the two-lane Main Street and Keene Bypass roundabouts in that city may be the best in the world on maximizing vehicle flows safely.

Until Winooski accesses experienced, knowledgeable folks who have dealt with literally hundreds of roundabouts—and Winooski officials resisted this advice in the past—they will continue to stumble in the dark and further risk higher levels of injuries than necessary.

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