gehrke slides, 01-23-2015
TRANSCRIPT
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
2
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
3
BackgroundToward a Spatial-Temporal Measure of Land Use Mix
4
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
5
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
6
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
7
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
8
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
9
Land Use InteractionToward a Spatial-Temporal Measure of Land Use Mix
10
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
? ? ?
Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions
11
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
Co
mp
osi
tio
n
Co
mp
lexi
ty
Background | Land Use Interaction | Geographic Scale | Temporal Availability | Conclusions
12
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
13
Geographic ScaleToward a Spatial-Temporal Measure of Land Use Mix
14
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
15
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
16
Temporal AvailabilityToward a Spatial-Temporal Measure of Land Use Mix
17
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
18
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
19
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
20
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
21
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
22
ConclusionsToward a Spatial-Temporal Measure of Land Use Mix
23
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
24
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
25
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
26
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
27
Thank you. Questions?Steven R. Gehrke [email protected] J. Clifton [email protected]