Andy Mortenson-Measuring Transportation Connectivity by RDI

measuringmeasuringmeasuring

Transportation ConnectivityTransportation Connectivitybybyby

Route Directness IndexRoute Directness Indexusingusingusing

*

* Trademarks provided under license from ESRI.

2009 Transportation Summit 2009 Transportation Summit –– Portland, OregonPortland, Oregon

Background Policy IssuesBackground Policy Issues

Z Complete Streets PolicyZ Concurrency Program RefinementsZ VMT and GHG per Capita ReductionZ Multi-Modal Level-of-Service (LOS)Z Street Connectivity Policies

Connectivity between new/existing developed landsNon-motorized public accessways and limiting cul-de-sacsGrid-based standards for streets (500 feet ) and Non-motorized (330 feet) –emphasis on smaller block lengthsDeveloping connectivity metrics

Cities are looking at a host of transportation, land use, energyCities are looking at a host of transportation, land use, energy, environmental and sustainability , environmental and sustainability policy issues and considering new measurement techniques:policy issues and considering new measurement techniques:

Testing Connectivity MetricsTesting Connectivity Metrics

Link / Node RatioIntersection Density

% 4-Way IntersectionsRoute Directness Ratio

1990’s Hierarchical Network

1990’s Hierarchical Network1950’s Grid Network

A B

C D

A B

C D

261 / 146 = 1.79107

40 %.74

158 / 143 = 1.1093

20 %.44

(Miles on Perimeter Arterial)0.4 2.7

Connectivity measurements in small subareas are straightConnectivity measurements in small subareas are straight--forward; but what about cityforward; but what about city--wide?wide?

Achieving VMT per Capita ReductionAchieving VMT per Capita Reduction

-25

-20

-15

-10

-5

0

% C

hang

e in

Per

son

Mile

s Tr

avel

led

Residential Office Park Retail / Service

Land Density Land Use Diversity Design

DESIGNAverage Block Size

% 4-Way Intersections% Sidewalk Coverage- 4 %

- 2 %

- 5%

Measures of connectivity help indicate transportationMeasures of connectivity help indicate transportation--efficient efficient land uses that yield lower VMT and GHG per capitaland uses that yield lower VMT and GHG per capita

Research conducted in Seattle area by C. Lee and Anne Moudon (University of Washington), 2006: Quantifying Land Use and Urban Form Correlates of Walking

Intersection DensityIntersection Density

Intersection Density 4-Way Intersection Density

GIS mapping techniques can illustrate cityGIS mapping techniques can illustrate city--wide measures of intersection density wide measures of intersection density but have difficulty illustrating but have difficulty illustrating ““PlanPlan”” benefitsbenefits

LinkLink--Node, Intersection Density and Walkscore Measures are only Node, Intersection Density and Walkscore Measures are only ProxiesProxies for for connectivity connectivity –– RDI is a direct measure of connectivityRDI is a direct measure of connectivity

Composite Accessibility IndicesComposite Accessibility Indices

Can help identify and prioritize plans, but miss the important mCan help identify and prioritize plans, but miss the important measure of system easure of system connectivity and notable gaps.connectivity and notable gaps.

Defining RDIDefining RDIZ Define Route

Directness Index

Z The Route Directness Index (RDI) can be used to quantify how well a street network connects destinations.

Z The RDI can be measured separately for motorized and non-motorized travel, taking into account non-motorized shortcuts, such as paths that connect cul-de-sacs, and barriers such as highways and streets that lack sidewalks.

Z The RDI is calculated by dividing direct travel distances by actual travel distances. For example, if streets are connected, have good sidewalks, and blocks are relatively small, people can travel nearly directly to destinations, resulting in a high index. If the street network has many unconnected dead-ends and blocks are large, people must travel farther to reach destinations, resulting in a low index.

RDI CreditsRDI Credits

Z Jennifer Dill, Portland State UniversityResearch – Connectivity Metrics

Z Victoria Transport Policy InstitutePolicy – Connectivity Metrics

Z Charlier & Associates & Otak Intl. – CNUPractice

Z Others

RDI Example: RDI Example: Pre Neighborhood Pre Neighborhood ConnectorConnector

Route Directness Index can better illustrate Route Directness Index can better illustrate ““beforebefore--andand--afterafter”” Plan improvementsPlan improvements

Existing Shared-Use Path

Route Directness IndexRoute Directness Index

Crow FlightCrow Flight

Walk DistanceWalk Distance

1850 ft1850 ft

1850 ft1850 ft

RDIRDI

RDI: .20RDI: .20

.20.20

//

==

375 ft375 ft

375 ft375 ft

Route Directness Index can better illustrate Route Directness Index can better illustrate ““beforebefore--andand--afterafter”” Plan improvementsPlan improvements

RDI Example: RDI Example: Post Neighborhood Post Neighborhood ConnectorConnector

Existing Shared-Use Path

Route Directness IndexRoute Directness Index

Crow FlightCrow Flight

Walk DistanceWalk Distance

RDIRDI==

375 ft375 ft

375 ft375 ft

RDI: .83RDI: .83

.83.83

New Neighborhood

Connectors

450 ft450 ft

450 ft450 ft

//

RDI RDI –– GIS Focal ExamGIS Focal Exam

Testing RDI on a larger, cityTesting RDI on a larger, city--wide scale is the challengewide scale is the challenge

Poor

Good

Examples Using RDI DesktopExamples Using RDI DesktopTMTM

Z Access to Commuter Rail Station

X Bike Access to LRT Station

Z Pedestrian Access to LRT Station

Z Neighborhood Design / Growth ManagementNon-Motorized Concurrency and Quality of

Service

Using Using RDI DesktopRDI Desktop to to demonstrate functional demonstrate functional implementation of a implementation of a Master Master PlanPlan area:area:

•• Measuring connectivity Measuring connectivity with & without with & without exclusive exclusive pedestrian routespedestrian routes

Z RDI Measure: Neighborhood Connectivity

Growth Management: Growth Management: NonNon--Motorized Concurrency and Motorized Concurrency and

Quality of ServiceQuality of Service11

Planned NeighborhoodPlanned NeighborhoodZ Neighborhood design:

Mixture of villa plot sizeNeighborhood centers

Z Maximized public realm for non-motorized connectivity through:

Quality street pedestrian zoneConnecting exclusive exclusive pedestrianpedestrian routes, and park/open spaces

Neighborhood RDI ScoreNeighborhood RDI ScoreZMeasured

withoutPedestrianPedestrianconnections

Z Fair RDI scores

Poor

Fair

ExcellentParcelParcel

RDI DesktopTM Metric

ParcelParcel

Average RDI Score: Fair .65

Neighborhood RDI ScoreNeighborhood RDI ScoreZMeasured with

PedestrianPedestrianconnections

ZGood-Excellent RDI scores

Poor

Fair

Excellent

ParcelParcel


ParcelParcel

Average RDI Score: Good .73

RDI scoring can be used to establish nonRDI scoring can be used to establish non--motorized motorized concurrency measuresconcurrency measures and and thresholds, used to evaluate future land thresholds, used to evaluate future land development plans for policy compliancedevelopment plans for policy compliance

Comparative RDI ScoringComparative RDI ScoringZRDI Score

Difference: Withand WithoutPedestrian Pedestrian connections

ParcelParcel


ParcelParcel

Plots that benefit significantly Plots that benefit significantly by by PedestrianPedestrian connectivityconnectivity

Intersection Density ScoringIntersection Density ScoringZ Intersection

Density Score Without SUPsSUPs

Poor

Fair

Excellent

Average Density Score: Poor 68

Intersection Density ScoringIntersection Density ScoringZ Intersection

Density Score With SUPsSUPs

Fair

Average Density Score: Good 142

Poor

Excellent

LinkLink--Node ScoringNode ScoringZNode-Link

Score WithoutSUPsSUPs

Link-Node Ratio: 1.66

LinkLink--Node ScoringNode ScoringZNode-Link

Score WithSUPsSUPs


SeattleSeattle’’s Mt. Baker s Mt. Baker Link LRT Station Link LRT Station

ExampleExample

Z RDI Measure: Pedestrian Access to LRT Station

Establish GIS DatabaseEstablish GIS DatabaseZ Study areaZ Light rail lineZ Street centerlineZ Parcel data

Create Pedestrian NetworkCreate Pedestrian NetworkZ Create Pedestrian

NetworkZ Illustrate

Importance of “Hanford Steps”

Calculate Base Year RDICalculate Base Year RDIZ Study Parcels

(2,000 foot radius buffer from LRT station)

Z Pedestrian RDI to Mt. Baker Station

Z Baseline Conditions (assumes no Hanford Steps)

Z RDI Average = 0.67

ParcelParcel


StationStation

Average RDI Score: Fair .67

Poor

Good

Calculate PMP RDICalculate PMP RDIZ Pedestrian RDI to

Mt. Baker StationZ RDI Impact of

Hanford Steps

Poor

GoodParcelParcel


StationStation

Average RDI Score: Good .72

Estimate RDI EnhancementEstimate RDI EnhancementZ Pedestrian RDI to

Mt. Baker StationZ Difference between

Baseline RDI and Hanford Steps RDI

Z Baseline: 58% of parcels above RDI 0.65 threshold.

Z Steps RDI: 73% of parcels above threshold.

Z Additional 40 more parcels.

RDI scoring can be used to sharpen plan RDI scoring can be used to sharpen plan priorities, particularly as federal and state priorities, particularly as federal and state

funding becomes more competitivefunding becomes more competitive

Intersection DensityIntersection DensityZ Without linkZ Average: 296

intersections per mi2

Poor

Good

Average Density Score: Fair 296

Intersection DensityIntersection DensityZ With projectZ Average: 302

intersections per mi2

Z Marginal increase

Average Density Score: Fair 302

Poor

Good

Comparing Station Area ScoresComparing Station Area ScoresBaseline Sidewalk Project Improvement

Average Score Average Score Increased Connectivity

Inte

rsec

tion

Den

sity

Rou

te D

irect

ness

In

dex

Not Available

Mea

sure

d C

onne

ctiv

ity B

etw

een

La

nd P

arel

s an

d LR

T S

tatio

n

Poor

Good

Poor

Good

Poor

Good

Poor

Good

RDI - .67 RDI - .72

Int / Sq Mi - 296

7.5 % Increase

Int / Sq Mi - 302

Improved Connectivity for 52 residential lots

2 % Increase

SeattleSeattle’’s Beacon Hill s Beacon Hill Link LRT Station Link LRT Station

ExampleExample

X RDI Measure: Bike Access to LRT Station

Import GIS DatabaseImport GIS DatabaseX Study areaX Light rail lineX Street centerlineX Parcel data

Create Bicycle NetworkCreate Bicycle NetworkX Create bike networkX Bicycle Master Plan

– existing conditions (2004)

Route Choice AnalysesRoute Choice AnalysesX Route Directness

Index

X Weighted Distance based on bicycle network characteristics Weighted Distance = Distance / [ [ x * (0.80) + y * (0.20)] * (0.10) ]

Impedancewhere Bike Facility Type (FT) Score (x) SDOT Code

Shared-Use Path 10 9, 23Bike Boulevard 9.5 8Bike Lane (both sides) 8 1, 16Bike Lane (one side) 6 2, 19Sharrow 5 3, 14Shared Lane 5 30, 40Shared (arterial) 2 10Shared (other) 0 15, 21, 77

Slopeand Slope Score (y)

< 2 % 102 - 4 % 84 - 8 % 58 -12 % 3> 12 % 0

Calculate Base Year RDICalculate Base Year RDIX Study parcels (one-

mile link distance)X Routes from parcels

to Beacon Hill Station

X Existing Conditions (2004)

Poor

Good

Calculate BMP RDICalculate BMP RDIX Added Bike Lanes

noted in Bicycle Master Plan (BMP)

Poor

Good

Estimate RDI EnhancementEstimate RDI EnhancementX Difference between

Existing RDI and BMP RDI

Alternatives AnalysisAlternatives AnalysisX Testing new Bicycle

Boulevard project to improve E-W connectivity

Poor

Good

BMP oriented mostly

north-south (arterials)…

…instead of to LRT sta.

RDI scoring can be used to identify RDI scoring can be used to identify supplemental master plans, using supplemental master plans, using detailed routedetailed route--choice analyses that choice analyses that

integrate integrate walkabilitywalkability and bicycle and bicycle compatibility indicescompatibility indices

RDI ComparisonRDI ComparisonX Difference between

BMP RDI and RDI with added Bike Boulevard project

Connectivity to LRTConnectivity to LRT

Poor

Good

Poor

Good

Baseline Measure:Baseline Measure:Bicycle Master Plan

Plan Refinement:

New Bicycle Boulevard

Bicycle System Connectivity ScoresBicycle System Connectivity Scores

Project Impact:

Improved Connectivity

NonNon--motorized System Plan motorized System Plan EvaluationEvaluation

Z RDI Measure: Pedestrian Network Connectivity

Existing ConditionsExisting Conditions

Shared-Use Path Connections

Average RDI Score: Poor / Fair .58

New SharedNew Shared--Use PathsUse Paths


Average RDI Score: Fair / Good .66 14 % improvement

RDI RDI –– ““Before & AfterBefore & After””


Sensitive to Block Sensitive to Block LengthLength

Sensitive to CulSensitive to Cul--dede--Sac LengthSac Length

305 ft 330ft

RDI scoring is sensitive to urban design RDI scoring is sensitive to urban design principles principles –– because it directly measures because it directly measures

connectivityconnectivity

RDI RDI –– ““Before & AfterBefore & After”” DeltaDelta


LinkLink--Node: BeforeNode: Before


Nodes 74

Links 107

Ratio 1.45


LinkLink--Node: AfterNode: After


Link-Node Ratio: 1.53 5.5 % improvement

Nodes 92

Links 141

Ratio 1.53

Lakewood Lakewood Sounder Commuter Rail Station Sounder Commuter Rail Station

ExampleExample

Z RDI Measure: Access to Commuter Rail Station

Shared-Use PathBike Lanes & Sidewalks

Non-Motorized Railroad OverpassI-5 Overpass Retrofit / Bike Lanes and Sidewalks

Option A

Option B

Sounder Commuter Rail

St Claire Hospital

115th Street

47th

Ave

nue

Non-Motorized Improvement Options

"Sharrow" - Shared-Lane

112th Street

111th Street

Lake

view

Ave

.

Brid

gepo

rt W

ay

Bike Lanes

LakewoodLakewood’’s NMTPs NMTPNew Pedestrian-Bicycle ConnectionsRR Over-crossing

I-5 Over-crossing

RDI RDI -- BaselineBaselineZ Testing RDI: Land Use – to

Sounder StationZ Land Use (building

structures) within One-Mile Radius

Z “Baseline” = Existing Pedestrian System Connectivity

Poor

Fair

Good

RDI RDI –– After IAfter I--5 Crossing5 CrossingZ Impact of I-5 Over-Crossing

ImprovementsZ Addition of Sidewalks and

Bike Lanes

Poor

Fair

Good

RDI RDI –– After RR CrossingAfter RR CrossingZ Impact of New Railroad

Over-CrossingZ Exclusive Non-Motorized

Facility

Poor

Fair

Good

Why Use Route Directness IndexWhy Use Route Directness Index

Z RDI metric can enumerate important quality of connectedness, a primary factor (along with land mix and density) in urban transportation sustainability by:

Directly measuring street / pathway connections, rather than proxy measures, andMapping spatial variation in land use connectivity

Z RDI calculates numerical metrics to evaluate the quality of a connection between an origin location and one or more destinations. These metrics can be mapped thematically at the origin location to highlight areas of connectivity quality (range, good-bad).

Z Using these metrics, before and after analyses can be performed to quantify and locate the impacts of improved connections (especially non-motorized connections), establishing Comparative RDI Benefit to Existing Land Use

Route Choice ModelingRoute Choice ModelingZ Non-motorized

system quality, or levels and types of obstacles (impedances) are important factors to consider in walking and cycling route choice sub-models

How Can RDI DesktopHow Can RDI DesktopTMTM Help?Help?

Z Street Design Policy Implementation – measurable guidelinesZ Establish Non-motorized Neighborhood Connectivity

StandardsDesign guide thresholds for neighborhood planning site plan review – non-motorized concurrency

Z Non-Motorized Plan Strategic PrioritizationMeasure current networks - target critical non-motorized connectionsMinimizing expensive and unnecessary data collectionHelp expedite Draft Non-motorized Plan project identification and prioritiesConsistently evaluate and rank multi-modal projects for federal Transportation Enhancement Program grant applications

Z Critical Plan Priority Analysis and Ranking – consistent and robust technique (with other sub-models) to measure important:

Neighborhood ConnectorsTransit Access ConnectorsUrban Boulevard Crossings

ContactContact

Andy MortensenAndy Mortensen

WHAT TRANSPORTATION CAN BE

[email protected]

503.313.6946

www.transpogroup.com

Abu Dhabi | Kirkland | Seattle | Boise

* Trademarks provided under license from ESRI.

*

Andy Mortenson-Measuring Transportation Connectivity by RDI

Technology

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