Transcript Slide 1

Synthesis of
Recent & Ongoing Studies:
Accessibility and Pedestrian
Safety at Roundabouts
Andrew T. Duerr, P.E.
Northeast US Roundabouts Peer Exchange
July 7, 2010
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Towson Roundabout
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1985
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2010
2015
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Historical Perspective
• Based Largely on European Experience
• NCHRP Synthesis 264 (1998)
• Roundabouts safe for Pedestrians because:
• Low Speeds
• Shorter Crossing Distances
• Fewer Conflict Points
• 2000 FHWA Roundabouts: An Informational
Guide
• Maintains prior assumptions
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Back to Towson
• Located near Balt. Co. Commission on
Disabilities
• CMCB files Complaint to DOJ
• DOJ defers to FHWA
• American Council for the Blind
Continues to Seek Roundabout
Moratorium
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Back to Towson
• FHWA Finds in Favor of SHA
• SHA offers Concessions
– Improved Wayfinding
– Detectable Warning Surfaces
– APS at Signals near the Roundabout
• Access Board begins to Focus on
Roundabouts (1999)
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Accessibility Research
• 1999 Western Michigan/Vanderbilt
– 3 roundabouts in MD (including Towson)
– 3 roundabouts in Tampa, FL
• 2000 National Eye Institute Study (NEIS)
• 2001 National Institute on Disability & Rehab
Research
• 2005 Human Factors Study
• 2006 FHWA Pedestrian Access to
Roundabouts
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Accessibility Research
• Summary of Findings – 1999-2006
– Poor Yield Rates – Unsignalized
Locations
– Noise makes Aural Gap Detection
difficult
– Identifiable Gaps may be Infrequent
– Visually Impaired Pedestrians experience
3s Delay (compared to Sighted Peds)
1980
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1985
1990
1995
2000
2005
2010
2015
2020
Access Board Perspective
• Accessibility is a Civil Right
• Safety ≠ Accessibility
• Courts finding 2005 Draft PROWAG to be
Best Available Guidance
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Pedestrian Safety Research
• 2006 NCHRP 562: Improving Pedestrian
Safety at Unsignalized Crossings
• 2007 NCHRP 572: Roundabouts in the
United States
• TØI Report 1009/2009
Subjective and Objective Safety: The Effect
of Road Safety Measures on Subjective
Safety among Vulnerable Road Users
– Institute of Transport Economics, Norway
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NCHRP 562
Improving Pedestrian Safety at
Unsignalized Crossings (2006)
– Recommend Treatments for:
• Pedestrian crossings
• High speed, high volume roadways
• Unsignalized intersections
– Recommend Modifications to MUTCD
Pedestrian Signal Warrants
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10
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2010
2015
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NCHRP 562
Treatment Categories
– Marked Crosswalk
– Enhanced, High Visibility, or Active When
Present devices
– Red Signal or Beacon Device
– Conventional Traffic Signal
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1985
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1995
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2005
2010
2015
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NCHRP 562
Findings & Conclusions
– Crossing Treatment Affects Compliance
• Only Signals > 95% Compliance Rate
– Other Factors Affect Compliance
• Width, Speed & Environment
– 1-Lane Roads – Compliance > 75%
– 2-Lane Roads – 30% to 100%
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2005
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NCHRP 572
Roundabouts in the US (2007)
– No Substantial Safety Problems Found
– Non-Yielding Rate 43% on 2-Lane Legs
– Additional Changes required to Improve
Yield Rates
• Design
• Operational
• Enforcement & Education
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2005
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2015
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TØI Report 1009/2009
Objective (Real) Ped Safety ↑
Subjective (Perceived) Ped Safety ↓
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2005
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2015
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On-Going Research
• NCHRP 3-78: Crossing Solutions at
Roundabouts and Channelized Turn Lanes
for Pedestrians with Vision Disabilities
• Golden, Colorado
• Oakland County, Michigan
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NCHRP 3-78
Crossing Solutions at Roundabouts and
Channelized Turn Lanes for
Pedestrians with Vision Disabilities
– Objectives:
• Identify/Test Treatments
• Analysis Framework
• Means to Extend Findings
– Expected Summer 2010
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NCHRP 3-78
Study Involved:
– Single-Lane Roundabouts
– Two-Lane Roundabouts
– Channelized Turn Lanes
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2010
2015
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NCHRP 3-78
4-Step Analysis Framework:
– Crossing Opportunity Criterion
– Crossing Opportunity Utilization Criterion
– Delay Criterion
– Safety Criterion
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NCHRP 3-78
Draft Findings:
– CTL’s are Challenging
– Low Speed S/L Roundabouts are
Accessible given Certain Conditions
– Pedestrian Hybrid Beacons & Raised
Crosswalks show Promise at 2-Lane
Roundabouts
– 2-Lane Roundabouts are Challenging
w/o Additional Treatments
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2015
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NCHRP 3-78
Future Research:
– Expand Number of Field Study Sites
– More Detailed Look at CTL’s
– Investigate Impact of Education
– Expand Study of Treatments at 2-Lane
Roundabouts
– Improve Field-Based Risk Performance
– Auditory Environment
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1985
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2015
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Synthesis of
Recent & Ongoing Studies:
Accessibility and Pedestrian
Safety at Roundabouts
Andrew T. Duerr, P.E.
[email protected]
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Eliminate/Reduce Conflict
• Grade Separation
• Simplify Geometry
– Eliminate or reduce entry/exit lanes
– Reorient pedestrian networks away from
Roundabout
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Minimize Pedestrian Exposure
• Simplify Roundabout Geometry
• Geometric Improvements
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Bulb outs
Raised cross walks
Buffer Strips between Sidewalk and Roadway
Low Speed Design
• Signalized Crossings
• ITS Solutions
• Police Enforcement
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Improve Gap Detection
• ITS Solutions
• Treatments that Provide Audible Cues
• Shift Crossings Downstream from Exits
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