Post on 24-May-2015
description
Measuring Connectivity as Measuring Connectivity as Implementation of Sustainable Implementation of Sustainable
CommunitiesCommunities
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Strength in Numbers……..Safety in Network
Presentation OutlinePresentation Outline
1. Connectivity & Safety – CNU Re-cap• Macro-scale connectivity measures
2. Local need for Micro-scale measures and tools
3. Comparing connectivity measures • Fire Station – Emergency Response • Transit Station Access (Sound Transit Pilot Study)• Sustainable Neighborhood Network Planning
Garrick / Marshall – Connectivity & Safe Streets
Source: Wesley Marshall and Norman Garrick | New Urban News and CNU Source: Wesley Marshall and Norman Garrick | New Urban News and CNU
CharacteristicCharacteristicSafer Safer CitiesCities
Less Less Safe Safe CitiesCities
Percent Percent DifferenceDifference
Average year of incorporation 1895 1932
Average year of block development 1957 1972
Population (2000 Census) 65,719 58,845 -8.9
Real intersection density (per sq mi) 106.2 62.7 -41.0
Average block size (acres) 18.2 34.5 89.6
Link to node ratio 1.34 1.29 -3.7
Fatal crashes 3.1 10.1 225.8
Fatal crashes not on limited access highways 2.3 8.6 273.9
Source: Wesley E. Marshall and Norman Glick, Street Network Types and Road Safety: A Study of 24 California Cities
safersafer less safeless safe
• Better connected cities are safer
• Intersection Density (better measure) & Link-Node Ratio
• Both measures – difficult for people to understand intuitively
Charlier Associates - Connectivity
Connectivity Measures:
• Block Length / Perimeter Length• Intersection Spacing• Link-Node Ratio• Intersection Density• Route Directness Index
Source: Charlier Associates, Scott McCarey Presentation | CNU Source: Charlier Associates, Scott McCarey Presentation | CNU
City of Charlotte
• Leading city in application of policy and macro-level connectivity measures for transit and fire station analyses Connectivity RatioConnectivity Ratio
Res
po
nse
Are
a (s
q m
i)R
esp
on
se A
rea
(sq
mi)
Emergency Response Emergency Response Service Area as a Function of Connectivity RatioService Area as a Function of Connectivity Ratio
poor good
Source: City of Charlotte, Danny Pleasant Study Presentation | CNU 2008Source: City of Charlotte, Danny Pleasant Study Presentation | CNU 2008
Drawbacks of Macro-Level Measures
Assumes a barrier-free landscape, measures only crow-flight distance linking selective land use.
Intersection
Density
Walk Score
Link-Node Ratio Only reflects cul-de-sac activity - insensitive to block length.
Reflects density of street development (block size).
None of the methods directly measure connectivity between None of the methods directly measure connectivity between individual land uses (parcel-level) and they are difficult to individual land uses (parcel-level) and they are difficult to interpret and explain to policy-makers and the general public.interpret and explain to policy-makers and the general public.
Local Need for Micro-scale MeasuresLocal Need for Micro-scale Measures• Macro-scale measures – key findings of public safety and
establishing standards with good urban design principles
• Micro-scale (direct measurement) tools are needed to advance standards at the individual land use (parcel) level.
• Need Examples:• Transit Station - FTA/HUD/EPA draft policy emphasizing
performance measures and importance of network and inter-modal connectivity
• Sustainable Neighborhood Network Planning - non-motorized QOS (emphasis on network) in balanced, multi-modal planning - Smart Growth and / or concurrency management
Refining Route Directness IndexRefining Route Directness Index
straight-line distance “A”straight-line distance “A”
B
RDI = A / BRDI = A / B
Aactual route distance “B”actual route distance “B”
shared-use path
RDI = 0.20RDI = 0.20 RDI = 0.83RDI = 0.83
shared-use path
RDI Applied - Neighborhood ExampleRDI Applied - Neighborhood Example
Comparing Connectivity MeasuresComparing Connectivity MeasuresFollowing three Case Studies compare connectivity measures:
• Node-Link ratio• Intersection Density• Walk Score• Route Directness Index (RDI)
Micro-level measure success indicators:• Recognizable individual land use (parcel) connectivity, and• Sensitivity to New Urban design principles:
(a) short block, and
(b) minimal dead-ends
Comparing Connectivity MeasuresComparing Connectivity Measures
Fire Station / Emergency ResponseFire Station / Emergency Response
RDI Baseline RDI - Project Impact
Fire Station / Emergency Response
Change in RDI
• Shows affected parcels and relative impact
Fire Station / Emergency Response
Route Directness Index
Before After Change
IntersectionDensity
Link-Node Ratio
55.955.9
56.056.0
0.480.48 0.570.57 19%19%
1.091.09 1.101.10
Walk Score 22 22 ofof 100 100
<1%<1%
<1%<1%
1,1151,115(increased Fire (increased Fire
Station Service Area Station Service Area by 17%)by 17%)
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Parcel Impact
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Fire Station
Comparing Connectivity MeasuresComparing Connectivity Measures
Public Transport PlanningPublic Transport Planning
Lakewood ExampleLakewood Example
Shared-Use Path
Bike Lanes & Sidewalks
Non-Motorized Railroad Overpass
I-5 Overpass Retrofit / Bike Lanes and Sidewalks
Option A
Option B
Sounder Commuter Rail
St Claire Hospital
115th Street
47
th A
ve
nu
e
Non-Motorized Improvement Options
"Sharrow" - Shared-Lane
112th Street
111th Street
La
ke
vie
w A
ve
.
Bri
dg
ep
ort
Wa
y
Bike Lanes
Improving Station ConnectionsImproving Station Connections
RDI AnalysisRDI Analysis
Before – without connectionsBefore – without connections
versus versus
After – with connectionsAfter – with connections
study area is 1.0 mile radius
Non-motorized connection across tracks with supporting pathways
Rail StationRail StationRDI Baseline RDI - Project Impact
Shows affected parcels Shows affected parcels and relative impactand relative impact
Impacted parcels can be Impacted parcels can be numbered for project numbered for project prioritizationprioritization
RDI ChangeRDI Change
Rail Station
taller parcels = higher land use density (address points per acre)taller parcels = higher land use density (address points per acre)
BeforeBefore AfterAfter ChangeChange
Land Use Density and RDI
Route Directness Index
Before After Change
IntersectionDensity
Link-Node Ratio
144144
146146
0.630.63 0.770.77 23%23%
1.291.29 1.301.30
Walk Score 89 89 ofof 100 100
1.4%1.4%
< 1%< 1%
2,3002,300
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Parcel Impact
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Rail Station
“ ” Draft FTA Policy – Connectivity NexusDraft FTA Policy – Connectivity NexusFTA encourages the use of its funds for the type of well-designed FTA encourages the use of its funds for the type of well-designed pedestrian and bicycle amenities that attract new public transportation pedestrian and bicycle amenities that attract new public transportation riders by expanding the catchment area and utility of public riders by expanding the catchment area and utility of public transportation stations.transportation stations.
Key requirement for determining the eligibility of a pedestrian or bicycle Key requirement for determining the eligibility of a pedestrian or bicycle improvement is improvement is whether it has a functional relationship to a public whether it has a functional relationship to a public transportation facility.transportation facility.
Pedestrian Improvements – within Pedestrian Improvements – within one-half mileone-half mile
Bicycle Improvements – within Bicycle Improvements – within three milesthree miles
(Proposed FTA Policy Statement on the Eligibility of Pedestrian and Bicycle Improvements Under Federal Transit Law. November 6, 2009) (Proposed FTA Policy Statement on the Eligibility of Pedestrian and Bicycle Improvements Under Federal Transit Law. November 6, 2009)
Comparing Connectivity MeasuresComparing Connectivity Measures
System-wide Transportation PlanningSystem-wide Transportation Planning
Anywhere USA: Variation in RDI
Cul-de-sacCul-de-sac
HybridHybrid
GridGrid
PoorPoor
FairFair
GoodGood
Street Network Typology Route Directness Index
Ave RDI = 0.58Ave RDI = 0.58
Ave RDI = 0.68Ave RDI = 0.68
Ave RDI = 0.75Ave RDI = 0.75
Neighborhood PlanBaseline Connectivity Ped-Bike Plan
Neighborhood Plan Shows affected parcels Shows affected parcels
and relative impactand relative impact
Impacted parcels can be Impacted parcels can be numbered for project numbered for project prioritizationprioritization
Route Directness Index
Before After Change
IntersectionDensity
Link-Node Ratio
107107
0.630.63 0.670.67 6%6%
1.431.43 1.551.55
Walk Score 38 38 ofof 100 100
9%9%
8%8%
268268
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Parcel Impact
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117117
Neighborhood Plan
City-Wide RDI Scoring: Olympia, WACity-Wide RDI Scoring: Olympia, WA
Pre-Planning Gap Analysis to Efficiently focus expensive data
collection
Begin community involvement process
Establish Concurrency Quality of Service Thresholds and Policy to Guide Site Planning
Gauge success of non-motorized projects and program (Plan) impacts on connectivity
ContactAndy MortensenViaCity Program Manager Sr. Transportation Planner
andy.mortensen@transpogroup.com
T 800.593.0597 Cell 503.313.6946
Bruce HaldorsPresident
bruce.haldors@transpogroup.com
T 800.593.0597 Cell 206.300.8907
www.viacity.info
Supplemental SlidedeckSupplemental Slidedeck
Neighborhood Baseline Conditions
Average RDI Scoring for Individual Tax
Parcels
Impact of New Shared-Use Paths
Average RDI Scoring for Individual Tax
Parcels
RDI Sensitivity to Smart Growth Design Principles
Block Block LengthLength
Cul-de-Sac Cul-de-Sac LengthLength
305 ft 330ft
Scoring Plan and Project Impacts
Shared-Use Path Connections
ViaCity softwareViaCity software
Data NeedsParcels or Tax Lots Street Centerlines Supplemental
Information
• Aerial Photos• Transit Facilities• Ped/Bike Facilities• Ped/Bike Plans• Planned
Improvements• Topography• Redevelopment
plans or ideas
(Analysis Layer) (Network Layer)
Network Editing
1 2 3 4
Identify link endpoints
Adapt for pedestrian-scale connections(major roads only)
Add existing internal connections
Add possible connections (scenarios)
Adding Impedances
• Impedances apply a factor to original street centerline length
• Good attributes reduce effective street length
• Bad attributes increase effective street length
Original length = 1.0 mileOriginal length = 1.0 mile
Effective length = 0.8 mile(bike lanes, good sidewalks)
Effective length = 0.8 mile(bike lanes, good sidewalks)
Effective length = 1.2 mile(high traffic volumes, steep, no sidewalks)
Effective length = 1.2 mile(high traffic volumes, steep, no sidewalks)
ViaCity Software
ViaCity Software
RDI Analysis
• Error checking
• Large parcel methods
• Opportunities for connections
• Review statistics
• Correlate to demographics
Patent pendingPatent pending Transit SitesTransit Sites Bike/Ped PlansBike/Ped Plans Project Project
PrioritizationPrioritization
IncorporateIncorporate ImpedancesImpedances Land useLand use Land valueLand value Any GIS dataAny GIS data
RDI Solutions – Work-In-ProgressRDI Solutions – Work-In-Progress
Transit Station Transit Station Area Project Area Project PrioritizationPrioritization
Cost / Benefit Cost / Benefit AnalysisAnalysis