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Roundabout Information and Benefits

Roundabouts are innovative, efficient and cost effective solutions to improve safety and traffic flow at highway intersections. Although new to the Guide Meridian (SR 539), roundabouts have been successfully used on other state and national highways for years.

      
At what intersections are we proposing roundabouts?
We propose to build two-lane roundabouts at Ten Mile Road, Wiser Lake Road, River Road and Pole Road (SR 544).  Given the number of accidents that occur at these intersections and increasing traffic volumes, roundabouts are an ideal way to enhance safety and keep traffic moving. 
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Why are we building roundabouts?
We are building roundabouts for three primary reasons: safety, public comments and traffic flow.
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How do roundabouts enhance safety?
Roundabouts are safe and have been proven to dramatically reduce serious accidents, especially fatal ones.  The Insurance Institute for Highway Safety reports that roundabouts sharply reduce crashes.  Researchers at Ryerson Polytechnic University found a 39 percent overall decrease in crashes and a 76 percent decrease in injury-producing crashes.  Collisions involving fatal or disabling injuries fell as much as 90 percent with the use of roundabouts instead of stop signs or traffic signals.   In addition, we will install a median to separate northbound and southbound traffic on the Guide.  While this will enhance driver safety, it will also restrict left turns in a number of locations.  The roundabouts will help drivers get where they want to go safely and conveniently after we install the median barriers.
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What has the public said about roundabouts in this area? 
People have told us that they are concerned about safety on the Guide Meridian.  In particular, people are concerned about dangerous and sometimes deadly head-on and side-swipe collisions that occur when people make left turns to get from the Guide to side roads or turn from side roads into Guide traffic.  We will install median barrier to help reduce the risk of these types of accidents.  Because median barrier restricts some turns, we proposed u-turns at traffic signals to help drivers get where they need to go.  After hearing many objections to these u-turns we redesigned the project to include roundabouts.
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How do roundabouts help keep traffic moving?
Roundabouts create a safe and continuous flow of traffic. How many times have you sat at a stop light waiting for it to turn green when there's little or no traffic?  Roundabouts eliminate this frustration and delay.  While you must slow down to go through the roundabout, you and other drivers steadily move through the intersection instead of waiting your turn for a traffic signal to turn green.  How many times have you sat at a stoplight on a side street until you finally decide to dart into fast moving traffic on a busy highway?  Roundabouts make it easier and safer for drivers to travel between less busy side streets and busy highways.   
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Why won't we build a mix of roundabouts and traffic signals?
We are strategically placing the roundabouts at four key intersections to help foster a safe and continuous flow of traffic along the Guide Meridian.  Roundabouts and traffic signals move traffic differently. Traffic signals create stop and go conditions while roundabouts create a continuous flow of traffic. If we placed both stop and go and continuous flow operations together, they could work against each other. 
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How will roundabouts affect traffic on the Guide Meridian?
The new roundabouts will allow traffic to flow more freely on both county roads and the Guide Meridian.  While they force traffic to slow down through the intersection, they allow continuous traffic flow instead of forcing drivers to wait at stop lights.  As shown at other locations, roundabouts keep traffic moving while improving safety significantly.
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Do roundabouts cause congestion and extend commute times?
No.  Roundabouts promote a continuous flow of traffic.  Unlike intersections with traffic signals, you don't have to wait for a green light at roundabouts to get through the intersection.  You only have to yield to oncoming traffic.  
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What is the speed limit through a roundabout?
We will set the speed limit through the roundabouts between 15 mph and 25 mph.  Drivers will have to slow down to enter and proceed through a roundabout.  However, slowing down to drive through a roundabout is faster than coming to a complete stop at a red light. 
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Can semi-trucks, fire engines, and other long vehicles make it through a roundabout?
Roundabouts provide a better, wider turning radius for semi-trucks and other long vehicles.  Even double trailer semi-trucks will be able to easily drive through the roundabouts.  You can watch how easily trucks and fire engines are able to drive through a roundabout in this "Driving a Roundabout" video. We also built a full-size Guide Meridian roundabout in a parking lot and invited local emergency responders, truckers and farmers to bring their biggest rigs and test-drive the roundabout; the results were surprising
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How will emergency vehicles get to locations where left turns have been prohibited?
We have strategically located roundabouts and gaps in the median barrier to provide sufficient access for emergency responders.  Specifically, we will have direct emergency vehicle access through the median barrier at East Bartlett Road, King Tut Road and Beard Road.
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Are roundabouts safe for pedestrians?
Yes, roundabouts are safe for pedestrians.  Roundabouts force cars to slow down, which makes crossing the street safer for pedestrians.  Cars are required to yield to pedestrians in roundabouts.
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How much does it cost to build one roundabout?
The cost difference between building a roundabout and a traffic signal is comparable.  However, cost is not the deciding factor for building these roundabouts.  Safety and traffic flow are.  It costs an estimated $330,000 to build a two-lane roundabout.  A typical intersection with traffic signals and a u-turn costs roughly $450,000.
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Why aren't you building roundabouts as part of the Horton Road to Ten Mile Road project?
We are widening Guide Meridian Road from Horton Road to Ten Mile Road and then from Ten Mile Road to Badger Road.  These were two separate projects that were designed at different times.  When we originally designed the SR 539, Horton Road to Ten Mile Road project, roundabouts were a relatively new concept in this area and weren't considered an option.  Since then hundreds of roundabouts have been built and successfully used in Washington State and nationwide, decreasing accidents and improving traffic flow.

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