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ITE Working Group on Roundabout Accessibility Issues (Slide 1)
A roundabout... (Slide 2)
- ... is an intersection with a generally circular shape.
- ... requires all entering traffic to yield to circulating traffic.
- ... has appropriate geometric features to ensure slow entering and circulating
speeds.
Roundabouts are a subset of circular intersections... (Slide 3)
Conversion of Rotary to Roundabout: Kingston, NY (Slide 4)
Photo: New York State DOT
Key Roundabout Features (Slide 5)
Exhibit 1-1, p. 6
Roundabouts versus Traffic Circles (Slide 6)
- Five key elements distinguish roundabouts:
- YIELD control on entry
- Priority to circulating vehicles
- Pedestrian access & crossing
- Parking
- Direction of circulation
Speed Reduction (Slide 7)
Speed Reduction (Slide 8)
Adequate Deflection
Little Deflection
Photos: Lee Rodegerdts
Settings (Slide 9)
- Mini-roundabouts
- Urban compact
- Urban single-lane
- Urban double-lane
- Rural single-lane
- Rural double-lane
Mini-Roundabout Examples: Germany (Slide 10)
Photos: Werner Brilon
Urban Compact Roundabout: Germany (Slide 11)
Photo: Werner Brilon
Urban Single-Lane Roundabout: Bend, OR (Slide 12)
Photo: Oregon DOT
Urban Double-Lane Roundabout: Clearwater, FL (Slide 13)
Photo: Bruce Robinson
Urban Multi-Lane Roundabout: Avon, CO (Slide 14)
Photo: Lee Rodegerdts
Rural Single-Lane Roundabout: Leeds, MD (Slide 15)
Photo: Maryland SHA
Photo: Lee Rodegerdts
Rural Double-Lane Roundabout Examples (Slide 16)
Australia
Photo: Austroads
Taneytown, MD
Photo: Lee Rodegerdts
Utrecht Province, The Netherlands
Photo: Eenheid in Rotondes, CROW
Typical Settings and Reasons for Implementation (Slide 17)
- Community Enhancements
- Traffic Calming
- Safety Improvements
- Operational Improvements
- Special Situations
Community Enhancements (Slide 18)
Located in areas where capacity and safety are not key issues
Naples, FL
Photo: Lee Rodegerdts
|
France
Photo: Joe Bared |
Traffic Calming (Slide 19)
Used for speed control in neighborhoods
Naples, FL
Photo: Lee Rodegerdts
Geography (Slide 20)
- International
- - 50,000+
- - 15,000+ in the UK and France
- US
- - 252 minimum
- - likely more than 500
252 US Roundabouts (Slide 21)
- 174 (69%) single lanes
- 56 (22%) are multi-lane
- 22 (9%) unknown
A brief history of roundabouts (Slide 22)
NCHRP Synthesis 264 (Jacquemart) (Slide 23)
ITE Journal, Sept. 2002 (Retting, et al.) Survey in KS, MD, and NV (Slide
24)
Pedestrian / ADA Issues (Slide 25)
- Positives
- Speed-controlled environment
- Splitter island provides refuge
- Negatives
- Pedestrians must assess gaps
- Disabled, children, and elderly may have difficulty
- Entries and exits with more than one lane are difficult
to cross
Pedestrians (Slide 26)
- General Principles
- Discourage use of central island
- Crossing set back from the yield line
- Splitter islands
- Perpendicular crossings
Visually Impaired Pedestrians (Slide 27)
- Navigation tasks:
- Locating the crosswalk
- Listening for a safe gap
- Splitter island pedestrian refuge
- Locating the correct path after the crossing
Pedestrian Crossing Design (Slide 28)
Exhibit 6-26, p. 157
Sidewalk Design (Slide 29)
Exhibit 6-40, p. 169
Pedestrians: Europe (Slide 30)
Source: Werner Brilon
Pedestrians: Annapolis, MD (Slide 31)
Photo: Ed Myers
Multi-modal Treatments: The Netherlands (Slide 32)
Separate bicycle track/path
Good Solution - safe - higher volumes
Source: Rotondes - CROW
Multi-modal Treatments: The Netherlands (Slide 33)
Ped/Bike Priority (urban areas)
 |
Vehicle Priority (rural areas)
 |
Source: Eenheid in Rotondes - CROW
Visually Impaired Pedestrians (Slide 34)
- Design Guidance:
- Optimal location of crosswalk
- Optimal orientation of crosswalk
- Application of textured pavements
- Raised crosswalks
- Traffic Control
- Other guidance issues
Visually Impaired Pedestrians (Slide 35)
- Technological Advancements:
- Flashing beacons
- Raised Crosswalks
- In-pavement flashers
- Pedestrian signals (midblock, actuated, ped activated)
- WMU research
