Roundabouts Turning Intersections into Circular Drives

Backed up at an intersection? Wary of those tough left-hand turns against oncoming traffic? A new roundabout might solve your traffic headache.

Roundabouts, or modern traffic circles, have grown in acceptance in recent years, cropping up across the country as an alternative to traffic signals and stop signs. Traffic engineers say the circular roadways help create free-flowing traffic and point to studies that show reductions in crashes and fatalities.

The circles have been popular in Europe, and the roadways have grown rapidly in the United States since the first modern one was built outside Las Vegas in 1990. More than 1,000 roundabouts are used nationwide, up from 300 to 500 five years ago, traffic experts estimate. Dozens more are on the drawing board.

States such as Colorado, Florida, Kansas, Maryland, Michigan, New York, Oregon, Utah and Washington state have been among the most active in building roundabouts.

“States and counties are finally catching on,” said Richard Retting, a senior transportation engineer with the Virginia-based Insurance Institute for Highway Safety.

In a roundabout, vehicles merge counterclockwise on a one-way road dotted with yield signs and constructed around a landscaped center. The circular thoroughfare lacks traffic lights and can have one or more lanes. Motorists entering the loop yield to drivers inside the circle.

Roundabouts are different from traditional traffic circles or rotaries because of their smaller size and reduced speed limits-most roundabouts typically limit speeds to 20 miles per hour (mph) to 25 mph, allowing for a steady, but less dangerous traffic flow.

In a rural patch of Ellicott City, a suburban community nestled between Washington and Baltimore, a roundabout replaced a two-way stop sign in 2003 at the base of a twisting, hilly road.

Cars frequently backed up behind two stop signs, and the site averaged nearly one crash a month. Motorists commonly tried to gun through the steady flow of traffic or make a tricky left-hand turn against traffic speeding down a secluded hill.

“We landed a (Medivac) helicopter here about once a year. We often said we have to put landing lights in,” recalled Bob Bassler, a researcher with the University of Maryland’s College of Agriculture, which has farmland adjacent to the roads.

Since the roundabout was put in place at the connecting point of Homewood Road, Sheppard Lane and Folly Quarter Road, traffic officials say there have been no crash reports.

When the roundabout first opened, Richard Cronin, a retiree who volunteers at a nearby Catholic ministry, initially thought it would make matters worse. “It has made it much better,” he said.

In Michigan, home of the nation’s first stop sign and traffic signal, about 20 roundabouts are currently in use, and another six are in planning stages, said Ed Waddell, a transportation planner with the state Department of Transportation.

In Okemos, outside of Lansing, Mich., traffic officials put a roundabout in place in 2004 near two schools as a solution to back-ups during peak hours-before and after classes-and concerns about young drivers taking risks at intersections.

“It’s difficult to move the traffic through with just stop signs. The roundabout has made the traffic just much more efficient,” said John Lanzetta, principal at Okemos High School.

Studies have shown the safety benefits. The Insurance Institute in 2001 found a 38 percent decline in crashes at roundabouts they studied, while crashes causing deaths and serious injuries dropped 89 percent.

“If that car does happen to have a collision with a car in a circle, it’s more of a sideswipe, and sideswipes are far less serious in regard to their potential for injury and death than a right angle crash,” said Eugene Russell, professor emeritus of transportation engineering at Kansas State University.

A study completed in September by the insurance industry of signalized intersections in northern Virginia said roundabouts would have reduced vehicle delays by 62 to 74 percent, depending on the intersection, and eliminate more than 300,000 hours of vehicle delay annually.

In many communities, proposed roundabouts have met resistance from those who favor traffic signals or question the cost. A roundabout project can cost anywhere from $200,000 to $400,000, depending on its location, the need to acquire land and other considerations.

Traffic engineers, however, note that the hardware for a traffic signal can exceed $100,000, and many intersections require expansions, left-turn signals and other expenses that add up and make the options comparable in price.

Others critics say the roundabouts create accessibility issues for the blind, citing concerns about the lack of crossing opportunities at roundabouts. Access could be improved by using self-activated cross-signals, said Dennis Cannon, an accessibility specialist with the Access Board, a federal agency that writes guidelines for the Americans with Disabilities Act.

Roundabout supporters say they expect America’s motorists to see them more frequently in coming years, but stress they will never fully replace stop signs and traffic lights.

“Not everyone loves them, but in streets and roads and traffic there is no panacea-there is no solution,” said Mark Johnson, a Madison, Wis.-based engineer who has developed roundabouts. “This is just another alternative.”

For more information, visit Roundabouts USA: http://www.roundabouts

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