18th Annual Congress of the New Urbanism "Building Safer Streets for Healthier Neighborhoods"

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


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


Before After Change

IntersectionDensity

Link-Node Ratio

144144

146146

0.630.63 0.770.77 23%23%

1.291.29 1.301.30


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)


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



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


Before After Change

IntersectionDensity

Link-Node Ratio

107107

0.630.63 0.670.67 6%6%

1.431.43 1.551.55


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

[email protected]

T 800.593.0597 Cell 503.313.6946

Bruce HaldorsPresident

[email protected]

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

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

18th Annual Congress of the New Urbanism "Building Safer Streets for Healthier Neighborhoods"

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Transcript of 18th Annual Congress of the New Urbanism "Building Safer Streets for Healthier Neighborhoods"