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    These kind of crashes do not occur at roundabouts

    Source: "Topeka News" - The Topeka Capital Journal (08/23/2002)

    Source: "Topeka News" - The Topeka Capital Journal (05/04/2001)

    People usually like direct routes when going from point A to point B.

    Perhaps that is why some Shawnee County residents are a bit concerned about a roundabout being installed at S.W. 29th and Urish.

    Shawnee County engineer Lynn Couch said he had received six calls by Tuesday about the construction of the roundabout. Construction started in late April. He said most callers were concerned with drivers cutting through business's parking lots to get to their destination, rather than following detours.

    Modern roundabouts move traffic in a counterclockwise circle. When drivers approach a roundabout, they yield to traffic coming from the left and enter the roundabout by turning right.

    A roundabout is a circular intersection that includes the following elements:
    YIELD AT ENTRY -- At roundabouts, the entering traffic yields to circulating traffic. This yield-at-entry rule keeps traffic
    from locking up and allows free-flow movement.
    DEFLECTION -- The splitter and center islands of a roundabout deflect entering traffic and reinforce the yielding process.
    FLARE -- The entries often flare out from one or two lanes to two or three lanes at the yield line to provide increased capacity to move traffic.

    While the Kansas Department of Transportation has put in two such roundabouts at the Interstate 70 and S.E. Rice Road interchange in Topeka, the modern roundabouts are still new to the area and the state as a whole.

    "Kansas doesn't have many at this point," said Eugene R. Russell, Kansas State University transportation engineering professor.

    Russell, along with some of his students, has been researching modern roundabouts for about three years. He said modern roundabouts have been growing in popularity.

    "The bottom line is we believe they are the safest, most effective way to direct traffic," Russell said.

    The beginning

    Modern roundabouts have worked in Australia and Europe since the 1960s, KDOT senior traffic engineer David Church said.

    "It's taken a number of years for the U.S. to start using modern roundabouts," he said.

    Church and Russell said many people confuse modern roundabouts with traffic circles.

    Russell said the central islands of most modern roundabouts have an average diameter of 20 to 30 feet. The diameters can reach up to 100 feet. If the island is 200 to 300 feet in diameter and the roundabout has multiple lanes of fast-moving traffic, it is considered a traffic circle.

    Russell said Great Britain almost gave up on roundabouts initially. The country researched the issue and found that if the roundabouts were smaller and lower speed limits were enforced, the traffic pattern worked.

    "It gets frustrating because many people don't have the facts about modern roundabouts," Russell said. "They base things on what they hear about DuPont Circle in Washington, D.C., or the traffic circle by the Arc de Triomphe in France. DuPont Circle is confusing. I don't disagree."

    Learning by example

    One Kansas intersection that has seen a high number of injuries now relies on a modern roundabout.

    Hutchinson installed a roundabout in fall 2000 after receiving a grant from KDOT requiring one at a problematic location, according to Stephen Williams, city civil engineer.

    "We had 19 injury accidents in a little more than a year at this intersection," he said.

    Williams said that in four months with the roundabout, two accidents occurred, but no one was injured.

    "The safety that comes with a roundabout far outweighs any cost," he said.

    Roundabouts are considered a safe way to flow traffic because they cause drivers to slow down.

    Shawnee County public works director Mike Sease said that if drivers obey the rules at the S.W. 29th and Urish roundabout, cars and trucks should move at about 20 mph.

    Russell also said that because traffic is constantly moving, not as much traffic will back up as at a four-way stop.

    The logistics

    When building a roundabout, engineers have to make sure it can handle any vehicle that may use it.

    Couch said the S.W. 29th and Urish roundabout is designed to handle semi-trucks making drop-offs at the nearby Dillons and school buses. He said the island is about 40 feet in diameter and the road is 16 feet wide. An additional 10 feet of concrete runup is being put in to handle large trucks using the roundabout.

    The S.W. 29th and Urish roundabout was designed by Cook, Flatt & Strobel Engineers, a local firm. President Darold Davis said that after doing an initial study, his firm recommended that the county install a traffic signal at the intersection.

    However, time and money also had to be considered.

    Sease said the traffic signal project would have cost $1 million or more while the roundabout project will cost about $160,000. Dillons, Mission Township and the Sherwood Improvement District are helping with the costs. Sease said the combination of new development in the area and the recent opening of Dillons increased the urgency of the project.

    The roundabout is expected to open in about two months.

    Rounding up

    Despite some opposition, Russell and Church said they believe roundabouts will become commonplace in the United States.

    "There's usually some opposition at first, but after a roundabout is installed, people flip-flop," he said. "People like them because they're safe and simple. It's really just a matter of giving modern roundabouts a chance."

    Church said KDOT will probably build another roundabout in several years at the intersection of US-75 highway and N.W. 46th.

    Russell said he tries to keep track of all of the roundabouts being built or in use in the United States, but he expects there will be too many to count someday.

    "People weren't too sure about traffic signals when those started going up," he said. "But people learned how to use them. I'm sure the same thing will happen with roundabouts."

    Source: "Opinion" - Lawrence Journal-World, Wednesday April 18, 2001

    Local traffic planners should make sure that the new traffic roundabout fad won't pose serious problems for fire trucks traveling to an emergency.

    Concerns about how traffic roundabouts affect fire trucks' ability to travel around Lawrence deserve the serious attention of local officials.

    Police cars en route to a recent accident on Harvard Road several blocks east of Wakarusa Drive reached their destination by traveling through the roundabout intersection on Monterery Way and then west on Harvard Road. A fire truck en route from the station at 3708 W. Sixth took a slightly longer route traveling to Wakarusa Drive and then back east on Harvard, but not through the roundabout.

    Although fire officials said the roundabout wasn't the only determining factor for the route taken by the truck, they also say they are working on a report about the effect of roundabouts on emergency travel. The ability of large fire trucks to get to their emergency destinations is something that should concern all Lawrence residents.

    That concern will increase along with the number of roundabouts approved at various locations in the city. One area of great concern should be Louisiana Street south of the Kansas University campus.

    Public Works Director George Williams said the city has been careful not to put roundabouts on "major routes." The city apparently is working with the fire department to determine major response routes that won't involve roundabout intersections.

    But looking at future plans for Louisiana Street, it's difficult to see how fire response routes to some parts of town would not be impeded. Up to seven roundabouts are being considered on Louisiana Street, including locations at Louisiana's busy intersections with 19th Street and 27th Terrace.

    Both 19th and Louisiana Streets provide important access to KU and Lawrence High School, as well as nearby residential areas. South of 23rd Street, Louisiana is the only through north-south street between Haskell Avenue and Iowa Street. It is difficult to see how it wouldn't be considered a "major route" for all traffic, especially emergency vehicles.

    It's not impossible for big fire trucks to negotiate traffic roundabouts, but the structures present special problem, especially for large ladder trucks with a wide turning radius. Trucks may have to jump curbs or travel against the normal traffic flow to make the turns. Hopefully, other drivers would have the sense not to stop inside a roundabout when a fire truck approaches, but even in the best of circumstances, the presence of roundabouts complicates travel for the large trucks.
    Many Lawrence residents have doubts about the advisability of so many traffic roundabouts on Louisiana Street even for everyday traffic. An awarencess of problems the structures pose for fire trucks will olny magnify those concerns. There may be a compormise that would reduce the number of obstructions planned for Louisiana Street, but here should be no compromise when it comes to providing the fastest, safest possible access for fire trucks to reach emergency destinations.

    Source: Traffic Engineering Lawrence Journal World Saturday, March 31, 2001

    Roundabouts, becoming more common in America's road system, reduce deadly automobile accidents at intersections by nearly 90 percent, researchers said.

    Richard Retting, of the Insurance Institute for Highway Safety, said drivers have to get over their skepticism of the modernized traffic circles.

    "Mistakes at roundabouts result in fender-benders. Mistakes at stop signs and traffic signals can be catastrophic," said Retting, an author of the study. "Thousands of needless injuries could be prevented."

    The study involved 24 intersections that were converted to roundabouts. In roundabouts, drivers merge on a one-way road built around a landscaped circle. Roundabouts, unlike older circular intersections, don't have traffic lights.

    There were 38 percent fewer accidents at the roundabouts studied, the report found. Wrecks with injuries fell by 76 percent and accidents that caused deaths and very serious injuries dropped 89 percent.

    About 300 roundabouts have been built in America in the past 10 years, including two in Lawrence. "It's slowly catching on," said Mike Niederhauser, a transportaion engineer for the state of Maryland. He said drivers initially complained that while roundabouts were popular in Europe, they wouldn't necessarily work in America.

    Retting and researchers from the University of Maine and Ryerson Polytechnic University in Toronto studied single and multilane roundabouts in California, Colorado, Florida, Kansas, Maine, Maryland, South Carolina and Vermont. Four of the intersections previously had traffic signals; 20 had stop signs.

    Researchers found motorists approach traditional intersections traveling about 30 mph, compared to about half that at roundabouts. The study said that there are about 700,000 accidents with injuries, causing $1.3 million damage, at intersections with traffic lights and stop signs in America each year. About half of all car crashes with injuries occur at intersections, researchers said.

    The design eliminates left turns, a major source of accidents, and rear-end collisions caused by drivers stopping suddenly at yellow lights. Also eliminated are accidents caused when a driver makes a right trurn into the path of fast-moving traffic.

    "The country has relied on traffic signals and signs since the advent of the automobile," Retting said. "If you have an intersection you put up a stop sign, and if it's too busy for that you put in a traffic signal, and if it's too busy for a traffic signal you put in an overpass."

    Retting said traffic signals cost about $150,000 at major intersections, while roundabouts cost between $50,000 and $400,000.

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    Kansas State University
    September 9, 2009