Road Diets and Roundabouts
Paul Zykofsky, AICP Local Government Commission
Sacramento, CA
“Classic Road Diet”
4 to 3 lanes
San Antonio TX On-street parking Median Bike Lanes
Center Turn-Lane
Road diets: reclaim street space for other uses Seattle WA
3 crash types can be reduced by going from 4 to 3 lanes: 1 – rear enders
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Road Diets and Traffic Operations 3 crash types can be reduced by going from 4 to 3 lanes: 2 – side swipes
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Road Diets and Traffic Operations
3 crash types can be reduced by going from 4 to 3 lanes: 3 – left turn/broadside
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Road Diets and Traffic Operations Road Diets in Seattle (4 to 3 lanes)
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 Before
Charlotte NC
After Before
Reclaiming road space creates room for bicycle
Charlotte NC lanes and pedestrian islands 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
Reality: Before Reality: After
Before/after studies: 1. Crash rate
14.0 12.6 12.0 34% Reduction 10.0
MVM) 8.4 8.0 (per
6.0 Rate 1 crash every 1 crash every 4.0 2.5 days 4.2 days Crash (146 per yr) (87 per yr) 2.0
0.0 Before After Before/after studies: 2. Injury rate
4.0 3.6 3.5
3.0
MVM) 2.5 68% Reduction (per 2.0
Rate 1.5 1 injury every 1.2 9 days 1.0 Injury (41 per yr) 1 injury every 0.5 30 days (12 per yr) 0.0 Before After
Before/after studies: 3. Speeding analysis
35.0% 29.5% MPH 30.0% 36
25.0% over 19.6% 20.0% 15.7% 15.0% Traveling 9.8% 8.9% 10.0% 7.5%
Vehicles 5.0% of
0.0% Before After Before After Before After
Percent North End Middle South End Before/after studies: 4. Traffic volumes
25,000 20,500 20,000 18,100 Day 15,000 per
10,000 Now 21,000+ Vehicles 5,000
0 Before After
Before/after studies: 5. On-street parking utilization
45% 41% 40% 35% 30% 29% Percentage 25% 20% 15% Utilization 10% 5% Parking 0% Before After Before/after studies: 6. Pedestrian volumes
3000 23% Increase 2,632 2500 2,136 2000
Pedestrians 1500 of 1000
Number 500
0 Before After
Before/after studies: 7. Bicyclist volumes
600 30% Increase 486 500 375 400 Bicycles 300 of
200 Number 100
0 Before After Road Diet — Before Pottstown, PA
Road Diet — After Pottstown, PA There’s potential on one-way streets too: Is this street operating at capacity?
Boise ID
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 68 Feet
La Jolla Boulevard, Bird Rock, San Diego, California Before
14 Feet
La Jolla Boulevard, Bird Rock, San Diego, California After La Jolla Boulevard, Bird Rock, San Diego After
La Jolla Boulevard, Bird Rock, San Diego After 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
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 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 8 vehicle-to-vehicle traffic signal control can produce conflicts substantial reductions in motor 8 vehicle-to- vehicle crashes.” pedestrian conflicts March 2000 Study by the Insurance Institute for Highway Safety
Before One pedestrian fatality per year
Bradenton Beach, FL, Intersection of State Routes 684 and 789
After Zero pedestrian fatalities in over 8 years Roundabouts and Pedestrians
18 mph
18 mph 14 feet
Grand Junction, Colorado
Sacramento, CA West River Drive and Orchard Lane Sacramento, CA West River Drive and Orchard Lane Roundabouts and Bicyclists Montpelier, VT University Place, WA
Davis, CA Roundabouts, Trucks and Fire Departments
Petaluma, CA — Roundabout at Corona Road and Sonoma Mountain Parkway Roundabout Fire Station #2, 1001 N. McDowell Blvd.
Petaluma, CA — Roundabout at Corona Road and Sonoma Mountain Parkway
Mountable Curb for large trucks, emergency responders
Petaluma, CA — Roundabout at Corona Road and Sonoma Mountain Parkway Mountable Curb can be used by large trucks, emergency responders
Fort Pierce, FL
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 => high speed (worse at 2-lane roundabouts)
Towson MD