gehrke slides, 01-23-2015

Toward a Spatial-Temporal Measure ofLand Use Mix

Steven R. GehrkeKelly J. Clifton, PhD

Civil & Environmental EngineeringPortland State University

Winter 2015 Friday Transportation Seminar Series | January 23rd, 2015

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P resentation O utl ine

I. Background: Research Context, Motivation, & Element Introduction

II. Land Use Mix: Strategies & Shortcomings in Element Representation

III. Conclusions: Element Synthesis & Research Implications

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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BackgroundToward a Spatial-Temporal Measure of Land Use Mix

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Research C ontext

Urban policies encouraging active travel, reducing auto dependence, and mitigating peak hour travel are often rooted in growth management strategies

Mixed use development improves built environment efficiencies and increases local accessibility to out-of-home activity locations

Variety of metrics established to evaluate effectiveness of mixed use policies in relation to travel

Research of interest to urban planning and public health fields

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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B enef its o f L and Use Mix

Transportation• Reduce auto travel, auto ownership, & emissions production• Induce rideshare and shared parking opportunities• Distribute travel demand across the day and week• Promote transit and active travel mode choice

Public Health• Locate variety of opportunities in close proximity• Heighten visible interest in built environment• Increase propensity for physical activity• Positive implications for physical and mental health

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Research Motivation

Problem• Despite purported benefits, practice remains guided by limited theory and empirical

evidence to substantiate land use mix as a construct impacting travel behavior

Objectives• Summarize current approaches to measuring land use mix, identify inherent limitations,

and propose a research agenda• Provide research and practice with an improved theoretical and empirical understanding

of the influence of land use mix on active travel behavior• Develop a land use mix measure(s) reflecting these behavioral relationships that may be

used to better inform time-sensitive transportation-land use policies

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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L and Us e Mix E lements

Land Use Interaction• Quantification of complementary activities• Proximity of synergistic activity locations has implications regarding viability of active travel

Geographic Scale• Spatial boundary selected to measure extent of land use interaction• Scale for representing built environment has influence on modeling determinants of travel

Temporal Availability• Opportunity to access activity location (or land use) at a specific time• Availability of activity locations has consequences for transportation-land use forecasts

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Land Use Mix

L and Us e Mix and Travel B ehavior

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

Demographics

TravelBehavior

ContextualFactors

Land Use Interaction

Geographic Scale

Temporal Availability

Built Environment

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Land Use InteractionToward a Spatial-Temporal Measure of Land Use Mix

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L a n d U s e M i x E l e m e nt :L a nd U s e I n terac t ion

Accessibility Measures

• Distance-based

Intensity Measures Pattern Measures

• Count-based

• Percent-based

• Composition

• Configuration

0.25 miles

1

2.5 %

Entropy0.73

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Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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L a n d U s e I n te ra ct i on:P a tter n M e a sur es

C o n f i g u ra t i o n C o m p l e x i t y

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Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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L a n d U s e I n te ra ct i on:C o nc eptua l a n d M e t hodologic al C o nc er ns

Conceptual Concerns• Limited consideration toward functional complementarity of land use types• Ideal level of mixing often represented as equal distribution of land use types• Insufficient attempts to link land use types with primary trip/tour purpose

Methodological Concerns• Variety of land use typologies linking mix to different travel purposes• Absence of spatial configuration as pattern measure• Trip segment rather than tour-level analysis

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Geographic ScaleToward a Spatial-Temporal Measure of Land Use Mix

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L a n d U s e M i x E l e m e nt :G e o gra phic S c ale

• Administrative• Statistical• Artificial

• Areal Buffer• Network Buffer• Activity Space

• Mental Maps

Fixed Scale: Statistical Sliding Scale: Areal Buffer

Fixed Scales Sliding Scales Perceptive Scales

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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G e o g ra p hi c S c a l e :C o nc eptua l a n d M e t hodologic al C o nc er ns

Conceptual Concerns• Single operationalization strategy selected for all travel modes• Single spatial extent selected for all travel purposes

Methodological Concerns• Measure mix at single trip end for all travel purposes• Insufficient attention to mix at both local and regional scales• Spatial extents for sliding scales rely solely on distance as impedance factor• Modifiable Areal Unit Problem• Uncertain Geographic Context Problem

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Temporal AvailabilityToward a Spatial-Temporal Measure of Land Use Mix

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Neighborhood-Level Site-Level

Te m p ora l A v a i l a b i l i ty :R e p resent ing Te mpora l Ava i lab i l i ty

S TAT I C

Entropy = 0.73 Available Land Use = School

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Neighborhood-Level Site-Level

Te m p ora l A v a i l a b i l i ty :R e p resent ing Te mpora l Ava i lab i l i ty

12am – 6am

Entropy = 0.25 Available Land Use = None

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Neighborhood-Level Site-Level

Te m p ora l A v a i l a b i l i ty :R e p resent ing Te mpora l Ava i lab i l i ty

6am – 6pm

Entropy = 0.48 Available Land Use = School

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Neighborhood-Level Site-Level

Te m p ora l A v a i l a b i l i ty :R e p resent ing Te mpora l Ava i lab i l i ty

6pm – 12am

Entropy = 0.38 Available Land Use = Community Center

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Te m p ora l A v a i l a b i l i ty :R e p resent ing Te mpora l Ava i lab i l i ty

Known Temporal Availability• Stated opening hours at which activity locations may be accessed

Assumed Temporal Availability• Fixed assignment of opening hours for all activity locations of a similar regime

Activity-related Temporal Availability• Imputed assignment of opening hours based on revealed activity participation

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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ConclusionsToward a Spatial-Temporal Measure of Land Use Mix

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Measurement Sy nthesis

Land Use MixElement

Level of Operational Complexity

Low Moderate High

Land UseInteraction

Classification Accessibility Intensity Pattern

Strategies • Distance-based • Count-based • Composition

• Percent-based • Configuration

GeographicScale

Classification Fixed Sliding Perceptive

Strategies • Administrative • Areal Buffer • Mental Map

• Statistical • Network Buffer

• Artificial • Activity Space

TemporalAvailability

Classification Known Assumed Activity-related

Strategies • Stated Hours • Assigned Hours • Imputed Hours

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Measurement Sy nthesis

Land Use MixElement

Level of Operational Complexity

Low Moderate High

Land UseInteraction

Classification Accessibility Intensity Pattern

Strategies • Distance-based • Count-based • Composition

• Percent-based • Configuration

GeographicScale

Classification Fixed Sliding Perceptive

Strategies • Administrative • Areal Buffer • Mental Map

• Statistical • Network Buffer

• Artificial • Activity Space

TemporalAvailability

Classification Known Assumed Activity-related

Strategies • Stated Hours • Assigned Hours • Imputed Hours

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Research I mplicat ions

Guide Transportation-Land Use Policies• Provide empirical measure to define neighborhoods along an activity spectrum• Identify travel outcomes anticipated for new mixed-use and neighborhood infill projects• Potential to guide other innovative policies related to:

(1) downtown activity and business retention(2) liberalization of opening hours(3) multipurpose shared spaces(4) shared parking arrangements

Provide travel demand modeling research a spatial-temporal mix measure• Link activity opening hours to land use availability when specifying pattern measures• Temporally-static measures likely underestimate true extent of land use mixing

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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P rel iminary Research

Element 1: Land Use InteractionGehrke, S.R. & Clifton, K.J. A structural equation modeling approach to examine the relationship between land use mix and walking. Lectern presentation at Association of Collegiate Schools of Planning Annual Conference, Philadelphia, PA, Oct. 31, 2014.

Element 2: Geographic ScaleGehrke, S.R. & Clifton, K.J. Operationalizing land use diversity at varying geographic scales and its connection to mode choice: Evidence from Portland, Oregon. Transportation Research Record: Journal of the Transportation Research Board. (forthcoming).

Element 3: Temporal AvailabilityGehrke, S.R. & Clifton, K.J. Toward a spatial-temporal measure of land use mix. Journal of Transport and Land Use. (forthcoming).

Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions

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Thank you. Questions?Steven R. Gehrke sgehrke@pdx.eduKelly J. Clifton kclifton@pdx.edu