Road Diets and Roundabouts

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Road Diets and Roundabouts

• Paul Zykofsky, AICP
• Local Government Commission
• Sacramento, CA

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Classic Road Diet
4 to 3 lanes
San Antonio TX
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On-street parking
Center Turn-Lane
Road diets reclaim street space for other uses
Seattle WA
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3 crash types can be reduced by goingfrom 4 to 3
lanes 1 rear enders
X
Road Diets and Traffic Operations
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3 crash types can be reduced by goingfrom 4 to 3
lanes 2 side swipes
X
Road Diets and Traffic Operations
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3 crash types can be reduced by goingfrom 4 to 3
lanes 3 left turn/broadside
X
Road Diets and Traffic Operations
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Road Diets in Seattle(4 to 3 lanes)
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Benefits of road diets for bicyclists and
pedestrians?

• Provide space to add bicycle lanes
• Reduce crossing distance
• Eliminate or reduce multiple threat crash types
• Install crossing island to cross in 2 simple
  steps
• Reduce top end travel speeds
• Buffer sidewalk from travel lanes (parking or
  bike lane)
• Reclaim street space for higher and better use
  than moving peak hour traffic

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Before
Charlotte NC
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After
Before
Reclaiming road space creates room for bicycle
lanes and pedestrian islands
Charlotte NC
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Case study Edgewater Drive Resurfacing Project
(Orlando, FL)

• 589,000 project scheduled in FDOT 5-year work
  plan
• FDOT open to 3-lane option if City takes over
  jurisdiction
• Changes must be accepted by neighborhood and
  business associations before/after studies

Before
Concept
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Reality Before
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Reality After
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Before/after studies 1. Crash rate
34 Reduction
1 crash every 2.5 days
1 crash every 4.2 days
(146 per yr)
(87 per yr)
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Before/after studies 2. Injury rate
68 Reduction
1 injury every 9 days
1 injury every 30 days
(41 per yr)
(12 per yr)
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Before/after studies 3. Speeding analysis
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Before/after studies 4. Traffic volumes
Now 21,000
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Before/after studies 5. On-street parking
utilization
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Before/after studies 6. Pedestrian volumes
23 Increase
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Before/after studies 7. Bicyclist volumes
30 Increase
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Road Diet Before Pottstown, PA
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Road Diet After Pottstown, PA
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Theres potential on one-way streets too Is this
street operating at capacity?
Boise ID
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Road Diet on one-way street This area was
recaptured from a 4th travel lane the street
took on a whole new life
Portland OR
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68 Feet
La Jolla Boulevard, Bird Rock, San Diego,
California Before
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14 Feet
La Jolla Boulevard, Bird Rock, San Diego,
California After
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La Jolla Boulevard, Bird Rock, San Diego After
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La Jolla Boulevard, Bird Rock, San Diego After
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Roundabouts Benefits Injuries and crashes
reduced 90 30 more traffic capacity Gateway
entry Pedestrian-friendly Low traffic
speeds Reduced noise Reduced emissions Reduced
maintenance Business-friendly
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Roundabout design characteristics
Separated sidewalk to direct peds to crosswalks
Slow speed exit
Splitter island
Truck apron
Lots of deflection for slow speeds throughout
Crosswalk 1 car length back
Slow speed entry with yield
Bend OR
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Roundabouts are safer
32 vehicle-to-vehicle conflicts
24 vehicle-to-pedestrian conflicts
Results of this study indicate that converting
conventional intersections from stop sign or
traffic signal control can produce substantial
reductions in motor vehicle crashes. March 2000
Study by the Insurance Institute for Highway
Safety
8 vehicle-to-vehicle conflicts
8 vehicle-to-pedestrian conflicts
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Before One pedestrian fatality per year
Bradenton Beach, FL, Intersection of State Routes
684 and 789 After Zero pedestrian fatalities in
over 8 years
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Roundabouts and Pedestrians
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18 mph
18 mph
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14 feet
Grand Junction, Colorado
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Sacramento, CA West River Drive and Orchard
Lane
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Sacramento, CA West River Drive and Orchard
Lane
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(No Transcript)
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(No Transcript)
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Roundabouts and Bicyclists
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Montpelier, VT
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(No Transcript)
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University Place, WA
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Davis, CA
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Roundabouts, Trucks and Fire Departments
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Petaluma, CA Roundabout at Corona Road and
Sonoma Mountain Parkway
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Roundabout
Fire Station 2, 1001 N. McDowell Blvd.
Petaluma, CA Roundabout at Corona Road and
Sonoma Mountain Parkway
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Mountable Curb for large trucks, emergency
responders
Petaluma, CA Roundabout at Corona Road and
Sonoma Mountain Parkway
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Mountable Curb can be used by large trucks,
emergency responders
Fort Pierce, FL
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• Roundabout problems for blind pedestrians
• Circulating traffic masks the sound cues the
  blind use to identify gaps and masks the sound of
  yielding vehicles
• Tangential circulating roadway, tangential exit
  gt high speed (worse at 2-lane roundabouts)

Towson MD
8-50