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Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package
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Modern Roundabouts: Safety & Mobility Wrapped in a Pretty Package

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http://www.ohm-advisors.com - Mad about Modern Roundabouts: Coupling Safety and Mobility. This presentation delivers a primer on roundabouts, the differences between roundabouts, traffic circles and …

http://www.ohm-advisors.com - Mad about Modern Roundabouts: Coupling Safety and Mobility. This presentation delivers a primer on roundabouts, the differences between roundabouts, traffic circles and rotaries, and the important rules of roundabouts.

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  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10 In their own way, rdbts may be intimidating to drivers. Single-lane rdbts are not really that hard to master, and drivers can acclimate to them rather quickly. However, the use of two or even 3-lane rdbts are not yet common and require a sophistication of design to get good results.
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10 Here are the fundamentals for roundabouts. These apply for all rdbts, from a mini-rdbt in a subdivision handling maybe 100 vph in its peak, up thru a 3-lane rdbt, with by-pass lanes, serving upwards of 7,000 to 8,000 vph.
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10 Again, you need to understand the score card for rdbts. Like other treatments there are good and bad points to consider. When done correctly … (summarize list) There have been a number of studies of US intersections converted from signals to Rdbts; they point to dramatic reductions in number & severity of crashes. Rdbts have far fewer conflict points. When used at interchanges, Rdbt = 6 merge + 6 diverge + 0 crossing = 12. Conventional ramps = 26 points, including 10 crossing.
  • Modern Roundabouts 09/23/10 For purposes of general guidance, note that I am suggesting that placing rdbts near RR grade crossings is a negative. However, there are an number of locations (many in the U.K, only a handful yet in the U.S) where a rail line passes directly thru the heart of a rdbt. It CAN be made to work; but the attempt should be left in the hands of experts.
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Modern Roundabouts 09/23/10
  • Transcript

    • 1. Jim Marcinkowski, PE ASCE, APWA & SWE Redding, California May 17, 2010
    • 2.  
    • 3.  
    • 4.
      • Short History of Driving in Circles
      • Some Roundabout Basics
      • Safety
      • Users (How To)
          • Pedestrians
          • Bicycles
          • Drivers
      • Mobility (Congestion)
      • Before/After Comparisons
      • Aesthetics
    • 5.
      • No Controls
      • Take Your Turn
      • Follow Rules of Road
    • 6.  
    • 7.
      • Right of Way Rule (Yield to Right)
        • STOP Signs
          • Police Control
            • Traffic Signals
              • Special Turn Lanes & Signals
              • Vehicle & Pedestrian Detection
              • Coordinated Signal Systems
    • 8.
      • Shape Controls
      • Movement
      View of Columbus circle, Circa 1915 (Courtesy: New York Department of Planning)
    • 9.
      • Circles, Small and Large
      • Really Big, High Speed Circles Are Called Rotaries
    • 10.
      • Yield-To-Right
      • Circulating traffic yield to the entering vehicles.
    • 11.  
    • 12.
      • Meanwhile in England…
    • 13.
      • Yield-To-Left
      • Entering vehicles yield to the circulating traffic.
    • 14.  
    • 15.  
    • 16.  
    • 17.  
    • 18.  
    • 19.  
    • 20.  
    • 21.  
    • 22.  
    • 23.  
    • 24.  
    • 25.  
    • 26.  
    • 27.
      • Roads Are The Most Dangerous
      • Public Facilities
      • On The Face Of The Earth
        • In the U.S., about 800 people are killed each week.
    • 28.  
    • 29. TRAFFIC SIGNALS ARE NOT SAFETY DEVICES
    • 30.
      • 32 Vehicle/Vehicle
      • 24 Vehicle/Pedestrian
    • 31.
      • 8 Vehicle / Vehicle
      • 8 Vehicle / Pedestrian
    • 32.  
    • 33. All crashes All injury crashes Serious injury & fatal crashes
    • 34.
      • Week by Week reporting of accidents (Feb, 2008)
      • - no accidents reported since 12/12/07 (source: West Bloomfield Township)
    • 35.
      • NO INJURY ACCIDENTS
      • Minor Damage
      • Majority of Citations
        • Failure to Yield
        • Unsafe Lane Change
    • 36. (17+ seconds curb to curb) (<4 seconds each crossing) Typical Intersection = 60’ vs. Roundabout = 13’ x 2
    • 37.  
    • 38.  
    • 39.  
    • 40.
      • Goals of Roundabouts:
        • Yield on entry
        • Slow, consistent speeds entering/ thru/ exiting
          • Size as small as practical
          • Path deflection on entry
        • Limits the number of vehicle to vehicle & vehicle to pedestrian conflicts
    • 41.
      • Narrated by
      • Paul W. Smith
    • 42.  
    • 43.
      • = Delay +
      • Fuel Wasted +
      • Pollution + …
    • 44.
      • Added Delay =
        • Fuel Consumption
        • Air Pollution
        • Noise
      • Excess Widening =
        • Resources to Pave
        • Storm Water Run Off
    • 45.
      • Expression of both:
          • Capacity
          • Driver perception
      • Ranges from ‘A’ (best) to ‘F’ (worst)
      • Primarily based on measure of average delay
    • 46.
      • Best demonstrated through a review of a case study:
        • US-23/THOMPSON ROAD
      • Tight Diamond Rural interchange
      • Thompson Road – 2 lanes
        • 2 lane bridge over US-23
      • US-23 – 4 lanes
        • On/off ramps – Single lane w/stop control
    • 47.  
    • 48.
      • Rural Interchange w/ Improvements
        • Widen Thompson Road to five lanes including bridge
        • Widen ramps for right and left turn lanes
        • Install traffic signals
        • Construction cost = $7 m
        • Need additional land
        • NOT SELECTED…
    • 49.
      • Roundabouts at Ramps
        • Do Not Widen Thompson Rd
        • Do Not Widen Ramps
        • Install Single-lane Roundabout at each ramp termini
        • Construction Cost = $ 2.5 M
        • No additional land needed
    • 50.  
    • 51.  
    • 52.  
    • 53.
      • Roundabouts At Ramps
        • Selected as the recommended alternative
          • Best LOS
          • Lowest delay
          • Lowest cost
    • 54.  
    • 55.  
    • 56.  
    • 57.
      • Half mile strip commercial area. 20,000 ADT
      • No access management = numerous turning conflicts
      • Existing pavement width = 80’ - “sea of pavement”
      • Two traffic signals w/third needed
      • New shopping center was being proposed.
    • 58.
      • Reduce speed through the section
      • Improve safety
      • Improve access for businesses and residential neighborhoods
      • Create pedestrian friendly environment
      • Improve aesthetics
    • 59.  
    • 60.
      • Reduce speed through the section
          • Reduction of 85 th percentile speed from 48 mph to 33 mph
          • Reduction in average delay time, i.e., it takes less time to drive this segment of road even with a 15 mph reduction in speed
    • 61.
      • Improve safety
          • Crash rate reduced 88% even with increased traffic flows from new development
          • Reduced severity of accidents
          • Reduce # of injuries.
          • Before rate = 10/year
          • After rate = 1/5 years
    • 62.
      • Improve access for businesses and residential neighborhoods
          • Over first five years after construction - 60% growth in sales tax revenue for this corridor. Nearly flat sales tax revenue growth for the rest of Golden, CO over same time period
          • Elimination of large traffic queues from parking lots
    • 63.
      • Create pedestrian friendly environment
    • 64.
      • Improve aesthetics
    • 65.  
    • 66.  
    • 67.  
    • 68.  
    • 69.  
    • 70.  
    • 71.  
    • 72.  
    • 73.  
    • 74.  
    • 75.  
    • 76.  
    • 77.  
    • 78.  
    • 79.  
    • 80.  
    • 81.  
    • 82.  
    • 83.
      • Defined roundabout
      • Use / location
      • Benefits
        • Safety
        • Traffic calming
        • Capacity
        • Environmental
          • Emissions - Stormwater
        • Aesthetics
    • 84.
      • Reduces the number & severity of crashes.
      • Reduces the number of conflict points.
      • Increases capacity, usually w/ fewer approach lanes.
      • Minimizes ROW needed.
      • Can be closely spaced (to structures, traffic signals or other Rdbts).
      • Adapts to unusual geometry.
    • 85.
      • May not be suitable for locations:
      • Imbalanced traffic flows,
      • Poor stopping sight distance,
      • Steep grades (>5%) w/ heavy truck traffic,
      • Close to railroad crossings,
      • Within system of coordinated traffic signals.
    • 86.
      • Existing congestion problems
      • Known safety problems
      • Balanced entering traffic volumes, or
      • High percentage turning movements
    • 87.
      • Roundabouts: An Information Guide, FHWA 2000
      • NCHRP 3-78 IMPROVING ACCESS TO ROUNDABOUTS AND CHANNELIZED TURN LANES FOR THE VISUALLY IMPAIRED
      • www.roundaboutsusa.com
      • www.ksu.edu/roundabouts/
      • www.alaskaroundabouts.com
      • www.roundabout.kittelson.com
      • West Bloomfield Township
      • RCOC
      • Dan Hartman – dhartman@ci.golden.co.us
      • Northeast Roundabouts
    • 88.
      • A Coupling of Safety and Mobility
      QUESTIONS?
    • 89.
      • Initial Costs To Build
        • Surface area paved
        • Staging construction
        • Traffic signs
        • Pavement markings
        • Traffic & pedestrian signals
        • Street lighting
      • Annual Costs To Operate
      • Electrical & Communication
      • Relamping
      • Depreciating equipment
      • Pavement markings
      • Crash damage to equipment
      • Emergency service providers responses to crashes
    • 90.
      • 8 Roundabouts in West Bloomfield Township / Farmington Hills – Joint MDOT, RCOC, City & Twp.
    • 91.  
    • 92.  
    • 93.  
    • 94.  
    • 95.  
    • 96.  
    • 97.  
    • 98.  
    • 99.  
    • 100.  

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