CNU Summit 2009 RDI

measuringmeasuring

Transportation ConnectivityTransportation Connectivitybyby

Route Directness IndexRoute Directness Index

usingusing

*

* Trademarks provided under license from ESRI.

2009 Transportation Summit – Portland, Oregon2009 Transportation Summit – Portland, Oregon

Background Policy IssuesBackground Policy Issues

Complete Streets Policy Concurrency Program Refinements VMT and GHG per Capita Reduction Multi-Modal Level-of-Service (LOS) Street Connectivity Policies

Connectivity between new/existing developed lands Non-motorized public accessways and limiting cul-de-sacs Grid-based standards for streets (500 feet ) and Non-motorized (330 feet) –

emphasis on smaller block lengths Developing connectivity metrics

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

Testing Connectivity MetricsTesting Connectivity Metrics

Link / Node Ratio

Intersection Density

% 4-Way Intersections

Route Directness Ratio

1990’s Hierarchical Network

1990’s Hierarchical Network1950’s Grid Network

A B

C D

A B

C D

261 / 146 = 1.79

107

40 %

.74

158 / 143 = 1.10

93

20 %

.44

(Miles on Perimeter Arterial)0.4 2.7

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

Achieving VMT per Capita ReductionAchieving VMT per Capita Reduction

-25

-20

-15

-10

-5

0

% C

han

ge i

n P

ers

on

Mil

es T

ravell

ed

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 transportation-efficient Measures of connectivity help indicate transportation-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 city-wide measures of intersection density GIS mapping techniques can illustrate city-wide measures of intersection density but have difficulty illustrating “Plan” benefitsbut have difficulty illustrating “Plan” benefits

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

Composite Accessibility IndicesComposite Accessibility Indices

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

Defining RDIDefining RDI

Define Route Directness Index

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

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.

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

Jennifer Dill, Portland State University Research – Connectivity Metrics

Victoria Transport Policy Institute Policy – Connectivity Metrics

Charlier & Associates & Otak Intl. – CNU Practice

Others

RDI Example: RDI Example: Pre Neighborhood Pre Neighborhood ConnectorConnector

Route Directness Index can better illustrate “before-Route Directness Index can better illustrate “before-and-after” Plan improvementsand-after” Plan improvements

Existing Shared-Use Path


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 “before-Route Directness Index can better illustrate “before-and-after” Plan improvementsand-after” Plan improvements

RDI Example: RDI Example: Post Neighborhood Post Neighborhood ConnectorConnector

Existing Shared-Use Path


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 – GIS Focal ExamRDI – GIS Focal Exam

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

Poor

Good

Examples Using RDI DesktopExamples Using RDI DesktopTMTM

Access to Commuter Rail Station

Bike Access to LRT Station

Pedestrian Access to LRT Station

Neighborhood Design / Growth Management

Non-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

RDI Measure: Neighborhood Connectivity

Growth Management: Growth Management: Non-Motorized Concurrency and Non-Motorized Concurrency and

Quality of ServiceQuality of Service11

Planned NeighborhoodPlanned Neighborhood Neighborhood design:

Mixture of villa plot size

Neighborhood centers

Maximized public realm for non-motorized connectivity through: Quality street

pedestrian zone Connecting

exclusive exclusive pedestrianpedestrian routes, and park/open spaces

Neighborhood RDI ScoreNeighborhood RDI ScoreMeasured

without PedestrianPedestrian connections

Fair RDI scores

Poor

Fair

ExcellentParcelParcel

RDI DesktopTM Metric

ParcelParcel

Average RDI Score: Fair .65

Neighborhood RDI ScoreNeighborhood RDI ScoreMeasured with

PedestrianPedestrian connections

Good-Excellent RDI scores

Poor

Fair

Excellent

ParcelParcel


ParcelParcel

Average RDI Score: Good .73

RDI scoring can be used to establish non-RDI 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 ScoringRDI Score

Difference: With and Without Pedestrian Pedestrian connections

ParcelParcel


ParcelParcel

Plots that benefit significantly Plots that benefit significantly by by PedestrianPedestrian connectivity connectivity

Intersection Density ScoringIntersection Density ScoringIntersection

Density Score Without SUPsSUPs

Poor

Fair

Excellent

Average Density Score: Poor 68

Intersection Density ScoringIntersection Density ScoringIntersection

Density Score With SUPsSUPs

Fair

Average Density Score: Good 142

Poor

Excellent

Link-Node ScoringLink-Node ScoringNode-Link

Score Without SUPsSUPs

Link-Node Ratio: 1.66

Link-Node ScoringLink-Node ScoringNode-Link

Score With SUPsSUPs


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

ExampleExample

RDI Measure: Pedestrian Access to LRT Station

Establish GIS DatabaseEstablish GIS Database Study area Light rail line Street centerline Parcel data

Create Pedestrian NetworkCreate Pedestrian Network Create Pedestrian

Network Illustrate

Importance of “Hanford Steps”

Calculate Base Year RDICalculate Base Year RDI Study Parcels

(2,000 foot radius buffer from LRT station)

Pedestrian RDI to Mt. Baker Station

Baseline Conditions (assumes no Hanford Steps)

RDI Average = 0.67

ParcelParcel


StationStation

Average RDI Score: Fair .67

Poor

Good

Calculate PMP RDICalculate PMP RDI Pedestrian RDI to

Mt. Baker Station RDI Impact of

Hanford Steps

Poor

GoodParcelParcel


StationStation

Average RDI Score: Good .72

Estimate RDI EnhancementEstimate RDI Enhancement Pedestrian RDI to

Mt. Baker Station Difference between

Baseline RDI and Hanford Steps RDI

Baseline: 58% of parcels above RDI 0.65 threshold.

Steps RDI: 73% of parcels above threshold.

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 Density Without link Average: 296

intersections per mi2

Poor

Good

Average Density Score: Fair 296

Intersection DensityIntersection Density With project Average: 302

intersections per mi2

Marginal increase

Average Density Score: Fair 302

Poor

Good

Seattle’s Beacon Hill Seattle’s Beacon Hill Link LRT Station Link LRT Station

ExampleExample

RDI Measure: Bike Access to LRT Station

Import GIS DatabaseImport GIS Database Study area Light rail line Street centerline Parcel data

Create Bicycle NetworkCreate Bicycle Network Create bike network Bicycle Master Plan

– existing conditions (2004)

Route Choice AnalysesRoute Choice Analyses Route Directness

Index

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 RDI Study parcels (one-

mile link distance) Routes from parcels

to Beacon Hill Station

Existing Conditions (2004)

Poor

Good

Calculate BMP RDICalculate BMP RDI Added Bike Lanes

noted in Bicycle Master Plan (BMP)

Poor

Good

Estimate RDI EnhancementEstimate RDI Enhancement Difference between

Existing RDI and BMP RDI

Alternatives AnalysisAlternatives Analysis 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 route-choice analyses that detailed route-choice analyses that integrate walkability and bicycle integrate walkability and bicycle

compatibility indicescompatibility indices

RDI ComparisonRDI Comparison 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

Non-motorized System Plan Non-motorized System Plan EvaluationEvaluation

RDI Measure: Pedestrian Network Connectivity

Existing ConditionsExisting Conditions

Shared-Use Path Connections

Average RDI Score: Poor / Fair .58

New Shared-Use PathsNew Shared-Use Paths


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

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


Sensitive to Block Sensitive to Block LengthLength

Sensitive to Cul-de-Sensitive to Cul-de-Sac LengthSac Length

305 ft 330ft

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

connectivityconnectivity

RDI – “Before & After” DeltaRDI – “Before & After” Delta


Link-Node: BeforeLink-Node: Before


Nodes 74

Links 107

Ratio 1.45


Link-Node: AfterLink-Node: 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

RDI Measure: Access to Commuter Rail Station

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

47th

Aven

ue

Non-Motorized Improvement Options

"Sharrow" - Shared-Lane

112th Street

111th Street

Lakevie

w A

ve.

Bri

dg

ep

ort

Way

Bike Lanes

Lakewood’s NMTPLakewood’s NMTPNew Pedestrian-Bicycle ConnectionsRR Over-crossing

I-5 Over-crossing

RDI - BaselineRDI - Baseline Testing RDI: Land Use – to

Sounder Station Land Use (building

structures) within One-Mile Radius

“Baseline” = Existing Pedestrian System Connectivity

Poor

Fair

Good

RDI – After I-5 CrossingRDI – After I-5 Crossing Impact of I-5 Over-Crossing

Improvements Addition of Sidewalks and

Bike Lanes

Poor

Fair

Good

RDI – After RR CrossingRDI – After RR Crossing Impact of New Railroad

Over-Crossing Exclusive Non-Motorized

Facility

Poor

Fair

Good

Why Use Route Directness IndexWhy Use Route Directness Index

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, and Mapping spatial variation in land use connectivity

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).

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 Modeling 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?

Street Design Policy Implementation – measurable guidelines

Establish Non-motorized Neighborhood Connectivity Standards Design guide thresholds for neighborhood planning site plan review – non-

motorized concurrency

Non-Motorized Plan Strategic Prioritization Measure current networks - target critical non-motorized connections Minimizing expensive and unnecessary data collection Help expedite Draft Non-motorized Plan project identification and priorities Consistently evaluate and rank multi-modal projects for federal

Transportation Enhancement Program grant applications

Critical Plan Priority Analysis and Ranking – consistent and robust technique (with other sub-models) to measure important: Neighborhood Connectors Transit Access Connectors Urban Boulevard Crossings

ContactContact

Andy Mortensen Andy Mortensen

WHAT TRANSPORTATION CAN BE

[email protected]

503.313.6946

www.transpogroup.com

Abu Dhabi | Kirkland | Seattle | Boise

* Trademarks provided under license from ESRI.

*

CNU Summit 2009 RDI

Technology

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