Roundabouts The Virginia Experience Purpose of Briefing Misconceptions Background on Roundabouts How they pertain to Virginia Definition & Operational Characteristics Roundabouts Vs. Traffic signals Considerations for Roundabouts Review Process Roundabouts have been around forever Roundabouts are unsafe to Pedestrians and Bicyclists The public avoids using Roundabouts They are unsafe next to schools Circular Intersection History U.S. Modern Roundabout History 1900 s - 1940 s Rotaries and Traffic Circles Used 1950 s Circular Intersections fell out of favor 1963 Great Britain redesigns the Circular Intersection 1980 s Modern Roundabout used throughout Europe and Australia 1990 s Modern Roundabout utilized in the U.S.» More than 1000 now built in U.S.» Over 300 more to be built this year alone 1990 First Modern Roundabout in Nevada 1992 Florida s first Modern Roundabout 1993 Maryland s first Modern Roundabout 1995 Vermont s first Modern Roundabout 2000 New York s first Modern Roundabout 2004 Pennsylvania s first Modern Roundabout 2004 New Jersey s first Modern Roundabout 2004 Delaware s first Modern Roundabout 2004 Virginia s first Modern Roundabout 1
Leading Roundabout States What Is a Roundabout? Colorado > 150 Washington > 95 Utah > 90 Oregon > 50 Florida > 40 Kansas > 35 California & Nevada > 20 each North Carolina > 15 New York > 18 A circular intersection joining two or more streets All turns are to the right The SAFEST at-grade intersection Not a Roundabout Differences Between Roundabouts and Circles / Rotaries Yield at the approach Vehicle Deflection Splitter Island to control speeds Is a Roundabout the Right Tool? Operational Comparison of Roundabouts Vs. Signals History of Accidents High proportionate of left turns Irregular Geometrics Vehicle Queues Less expensive means of control Sufficient Right-of-Way Enhanced safety Intersection efficiency traffic moves Potential air quality benefits Lower cost to build & operate Fuel Savings Improved aesthetics U-turns are allowed 2
Vehicle-Vehicle Crossing Conflicts INSURANCE INSTITUTE FOR HIGHWAY SAFETY CRASH REDUCTIONS FOLLOWING INSTALLATION OF ROUNDABOUTS IN THE UNITED STATES MARCH 2000 Signalized Intersection Diverging 8 Merging 8 Crossing 16 Total 32 Roundabout Design Diverging 4 Merging 4 Crossing 0 Total 8 Reduction of Total Crashes by 39% Reduction of Injury Crashes by 76% Reduction of Fatal and Incapacitating Crashes by 89% On the web at: www.highwaysafety.org Safety Benefits Construction Time Based on 15 Single Lane Roundabouts in Maryland in 2004 Fatal Crashes down 100 percent Total crash rate down 60 percent Injury crash rate down 82 percent Property damage down 27 percent DEPENDING ON THE TECHNIQUES USED, IT MAY TAKE FROM THREE WEEKS TO THREE MONTHS TO COMPLETE CONSTRUCTION OF A ROUNDABOUT Special Considerations/Concerns Public Attitude Toward Roundabouts - Before and After Construction Public Acceptance Driver Inexperience Pedestrians / ADA concerns Bicycles Emergency vehicles Lighting Concerns Right of Way requirements Attitude Before After Construction Construction Very Negative 23% 00% Negative 45% 00% Neutral 18% 27% Positive 14% 41% Very Positive 0% 32% 3
Public Involvement Community Acceptance Public resistance is common Before construction: 2 to 1 against roundabout Education is crucial After construction: 3 to 1 in favor of roundabout Visualizations & traffic simulations are very helpful Main Vail - Diamond Interchange $2M (8,200 vph) Community Acceptance Vail, CO Constructed Oct. 1995 Voted Best Public Works Project 5 Years Straight Public Opinion WILL Change The director of the Charles R. Wood Theater said she was skeptical when the Greenwich roundabout was first talked about. "I'm not an expert on traffic, but I was convinced it wasn't going to work out," she said. Now, she describes driving through the circular intersection as an awesome experience. "I guess sometimes you just have to trust the opinions of traffic experts," she said. Pedestrian Consideration Unless All Red Signals Provide No Protected Pedestrian Phase Benefits: Easy to determine gaps Cars only coming from one direction Fewer lanes to cross Splitter Island provides refuge Slower Speeds Trade Offs: Must assess gaps No protected phase??? 4
SUMMARY-Why Safer for Pedestrians? 2003 Legislative Action Much lower number of conflict points. Because all vehicles travel the same direction in a roundabout, the number of vehicle/pedestrian conflict points is much lower than at intersections controlled by traffic signals. Vehicles [are forced] to approach and travel through slowly. This maximizes the time that pedestrians and motorists have to avoid conflicts. Non-attentive driving eliminated. For example, vehicle/pedestrian crashes that occur when motorists run red lights and ignore stop signs do not happen at roundabout intersections. The horizontal curvature of the roundabout forces drivers to pay attention to their surroundings as they approach and pass through the intersections. Pedestrian exposure to traffic is much lower. House Joint Resolution 594. Resolved, That the Department of Transportation be encouraged to construct more roundabouts instead of signalized intersections; Roundabouts; An Informational Guide Roundabout Informational Pamphlet FHWA Document Publication Number RD-00 00-067067 SIDRA Software Used to determine feasibility, appropriate geometric configuration and functional capabilities in regards to volumes and level of service. Roundabouts in Virginia Why Use a Roundabout? How to Drive Roundabouts Review and Approval Process Items the Committee Reviews District Existing & Proposed Subdivisions Secondary System up to Design Volume of 10,000 VPD Roundabout Review Committee Secondary System over 10,000 VPD All Urban and Primary Systems Approach Grades and sight distances All Geometrics Pedestrian crossing locations Pavement markings Signing 5
Items the Committee Reviews When to Submit Roadway Lighting (desirable) Nearest entrance locations and nature of property use Initial or present and projected design year traffic counts on all approaches Turning movements for all directions Early on, as soon as the preliminary plans are completed or a proposed site is selected. The Committee will assist the Districts in their review when asked. Review Time ROAD DESIGN MANUAL Typical, allow two weeks for the Committee s review. The information that we have mentioned today regarding the Roundabout Approval Process and the Data to be Submitted for Review will be included in the July 2006 Revision of the Road Design Manual. Charlottesville Airport Roundabouts in Virginia 6
Gloucester City of Richmond Va Tech Campus Powhatan Courthouse Christopher Newport Town of Amherst 7
amherst.jpg (882 KB) Amherst Circle 1940 Plan Sheet Gordonsville Circle Roundabouts Yes or No Roundabout Review Committee We Keep Virginia Moving Terry Knouse, PE - Location & Design Steve Edwards Traffic Engineering Walter Pribble Transportation & Mobility Planning QUESTIONS?? Roundabouts The Virginia Experience 8