Single-Lane Roundabout Presentation GVCC
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Transcript of Single-Lane Roundabout Presentation GVCC
![Page 1: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/1.jpg)
Single-Lane Roundabouts Implementation and Justification
![Page 2: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/2.jpg)
Federal Highway Administration Proven Safety Countermeasures • FHWA published guidance memorandum in 2012
• Promoted implementation of effective safety countermeasures
• Roundabouts listed high for reduction of fatal and injury crashes
![Page 3: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/3.jpg)
What Is a Roundabout?
• A circular intersection
• Yield control
• Splitter islands
• Reduced speeds
• Not a traffic circle
• Not a rotary
![Page 4: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/4.jpg)
Safety Benefits
• Roundabouts eliminate 75% of conflict points
• All crossing conflicts are eliminated
LegendVehicle-to-vehicle conflict point
Vehicle-to-pedestrian conflict point
Modern Roundabout Standard Intersection
![Page 5: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/5.jpg)
Safety Benefits
• FHWA and “Insurance Institute for Highway Safety” studies show roundabouts reduce crashes
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6
Typical Signalized Intersection Crash Types
• Right angle
• Rear end
• Left turn
• Sideswipe
• Pedestrian/bicycle
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Traffic Operations Benefits
• Traffic simulations for Pima County intersections show significant delay reductions for roundabouts over all-way stops and traffic signals
AM Peak Hour Total Cumulative Delay (Hours)
All-Way Stop Traffic Signal Roundabout
Los Reales Rd and Swan Rd 6.1 3.9 2.7
Continental Rd and Whitehouse Canyon Rd
3.3 3.2 2.3
Lambert Ln and Shannon Rd 2.6 2.6 1.6
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Environmental Benefits
• Limit noise pollution
• Reduce fuel consumption and emissions
30%
32%
34%
37%
42%
0 20 40 60 80 100
Fuel Consumption
Carbon Monoxide
Nitrous Oxide
Carbon Dioxide
Hydrocarbons
Percent Reduction of Fuel Consumption and Emissions for a Roundabout Compared to a Traffic Signal
Roundabout Traffic Signal
Source: Nevada Department of Transportation
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Usability Benefits • Power outages do not change the operation of a roundabout
• Roundabouts are user friendly for drivers of all ages and experience levels
• Roundabouts have high usability for pedestrians and bicyclists
![Page 10: Single-Lane Roundabout Presentation GVCC](https://reader034.fdocuments.in/reader034/viewer/2022042610/577c804a1a28abe054a80b84/html5/thumbnails/10.jpg)
Pima County Experience
• In 2009, Pima County constructed a roundabout at Camino Del Sol and Continental Road
• Safety has improved
• 12 crashes in five years before
• 0 crashes in five years after
• Green Valley residents are pleased
• Report more efficient traffic operations
• Describe the yield control as intuitive and familiar
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Roundabout Examples
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Roundabout Examples
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(Summary)Benefits of Single-Lane Roundabouts • Fewer conflict points: reduce frequency and severity of crashes
• More efficient than traditional intersections
• Reduce noise pollution, emissions, and fuel consumption
• Lower lifecycle maintenance costs
• Comparable or lower construction costs versus traffic signals
• Simple to use with high driver acceptance rates
• Reduces the speed of the vehicle traveling through intersection
• Eliminates multiple-threat pedestrian crashes
• Self-regulating and durable