Modern Roundabouts James H. Ito, P.E. 11/6/2015 Active Traffic Alternatives Introduction 11/6/2015 Modern Roundabouts became an effective Traffic Control strategy in 1966 when the British adopted the “Yield upon.
Download ReportTranscript Modern Roundabouts James H. Ito, P.E. 11/6/2015 Active Traffic Alternatives Introduction 11/6/2015 Modern Roundabouts became an effective Traffic Control strategy in 1966 when the British adopted the “Yield upon.
Modern Roundabouts James H. Ito, P.E. 11/6/2015 Active Traffic Alternatives 1 Introduction 11/6/2015 Modern Roundabouts became an effective Traffic Control strategy in 1966 when the British adopted the “Yield upon Entry” rule. I am currently the Traffic and Lighting Traffic and Lighting Design Engineer for the City of Milwaukee and the President of Active Traffic Alternatives. Active Traffic Alternatives 2 Topics of Discussion I will identify the distinguishing features of Modern Roundabouts You will learn why Modern Roundabouts are being built 11/6/2015 You will see images of Wisconsin’s Modern Roundabouts, those in use and some of those proposed Active Traffic Alternatives 3 What is a Modern Roundabout? 11/6/2015 Modern Roundabouts are part of the Family of Circular Intersections Active Traffic Alternatives 4 11/6/2015 Active Traffic Alternatives 5 What is a Modern Roundabout? Modern Roundabouts are part of the Family of Circular Intersections Distinguishing Features Yield at Entry Speed Control by Deflection 11/6/2015 Active Traffic Alternatives 6 11/6/2015 Active Traffic Alternatives 7 Why Build Modern Roundabouts? They Enhance Safety & Reduce Delay 11/6/2015 Conflict Points Reduced Active Traffic Alternatives 8 11/6/2015 Active Traffic Alternatives 9 Why Build Modern Roundabouts? They Enhance Safety & Reduce Delay 11/6/2015 Conflict Points Reduced Crash Reduction Statistics Active Traffic Alternatives 10 11/6/2015 Active Traffic Alternatives 11 Before and After Results for 24 Intersections in US Converted from Stop Sign or Traffic Signal Control to Modern Roundabouts 11/6/2015 89% Reduction in Fatal and Incapacitating Injury Crashes 76% Reduction in All Injury Crashes 39% Reduction for All Crashes Active Traffic Alternatives 12 Why Build Modern Roundabouts? They Enhance Safety & Reduce Delay 11/6/2015 Conflict Points Reduced Crash Reduction Statistics Traffic Delays Minimized Active Traffic Alternatives 13 11/6/2015 Active Traffic Alternatives 14 What Do They Look Like? 11/6/2015 Howard Roundabouts Active Traffic Alternatives 15 11/6/2015 Active Traffic Alternatives 16 11/6/2015 Active Traffic Alternatives 17 11/6/2015 Active Traffic Alternatives 18 What Do They Look Like? 11/6/2015 Howard Roundabouts Proposed Roundabout in Milwaukee Active Traffic Alternatives 19 11/6/2015 Active Traffic Alternatives 20 What Do They Look Like? 11/6/2015 Howard Roundabouts Proposed Roundabout in Milwaukee Proposed Roundabout in Mount Horeb Active Traffic Alternatives 21 11/6/2015 Active Traffic Alternatives 22 What Do They Look Like? 11/6/2015 Howard Roundabouts Proposed Roundabout in Milwaukee Proposed Roundabout in Mount Horeb Proposed Roundabout in Brookfield Active Traffic Alternatives 23 11/6/2015 Active Traffic Alternatives 24 Traffic Control Panacea? 11/6/2015 Modern Roundabouts should not be used in a Traffic Signal System Modern Roundabouts can be installed next to Signalized intersections Modern Roundabouts complement Traffic Calming Devices Modern Roundabouts enhance Street Landscaping and are often used to create Area Gateways Active Traffic Alternatives 25 11/6/2015 Active Traffic Alternatives 26 11/6/2015 Active Traffic Alternatives 27 What This Means 11/6/2015 Modern Roundabouts offer Communities and Neighborhoods an Attractive, Safe, and Efficient form of Traffic Control Modern Roundabouts can be more Efficient and Safer than traffic signals Modern Roundabouts should not be used in a Traffic Signal System Active Traffic Alternatives 28 What Has Happened 11/6/2015 Wisconsin Department of Transportation, Bureau of Transportation Safety funded Training, 1998 through 2001 Howard Modern Roundabouts have been constructed Roundabouts have been designed for several Wisconsin locations Wisconsin DOT has an Engineer on staff with Modern Roundabout Design Experience from Colorado Active Traffic Alternatives 29 Who To Contact? 11/6/2015 Ray Smith, Brown County Highway Department, 920-492-4925 Mark Johnson, Wisconsin DOT, District 1, 608-246-3842 James Ito, City of Milwaukee, DPW, 414-286-3263 Your BOTS Regional Program Manager Active Traffic Alternatives 30 Geometric Design Recommendations 11/6/2015 Iterative Process Hand Sketching Preliminary Designs Fastest Vehicle Paths Truck Swept Paths Radial Alignment of Entries Vehicle Path Overlap Extended Splitter Island Treatment Successive Curves on HS Approach Active Traffic Alternatives 31 11/6/2015 Active Traffic Alternatives 32 11/6/2015 Active Traffic Alternatives 33 11/6/2015 Active Traffic Alternatives 34 11/6/2015 Active Traffic Alternatives 35 11/6/2015 Active Traffic Alternatives 36 11/6/2015 Active Traffic Alternatives 37 11/6/2015 Active Traffic Alternatives 38 11/6/2015 Active Traffic Alternatives 39 11/6/2015 Active Traffic Alternatives 40 11/6/2015 Active Traffic Alternatives 41 11/6/2015 Active Traffic Alternatives 42 11/6/2015 Active Traffic Alternatives 43 11/6/2015 Active Traffic Alternatives 44 11/6/2015 Active Traffic Alternatives 45 11/6/2015 Active Traffic Alternatives 46 11/6/2015 Active Traffic Alternatives 47 Capacity Software 11/6/2015 ARCADY – British method with 50 % confidence limits. Capacities predicted have been measured. Has crash prediction module. RODEL – Same as ARCADY but with user specified confidence limits. SIDRA – Australian method based on gap acceptance processes. Active Traffic Alternatives 48 Simulation Models 11/6/2015 Simulation model results are best used for relative comparisons. Do not conclude that the values found from the model are the same as field data. Perform sensitivity analysis by changing selected parameters over a range and comparing results. Active Traffic Alternatives 49 QUESTIONS? COMMENTS? 11/6/2015 Active Traffic Alternatives 50