Modeling 4D Benefits of Compass Blueprint

1
Modeling 4D Benefits of Compass Blueprint

• J. Richard Kuzmyak,
• Transportation Consultant, LLC
• Caliper Corporation
• Transportation Conformity Working Group Meeting
• September 25, 2007

2
Study Purpose

• Quantify effects of Blueprint land use concepts
  on travel and air quality
• Regional (4-step) models are insensitive to
  important land use characteristics (4Ds)
• Density
• Diversity (land use mix and balance)
• Design (connectivity, scale, walkability)
• Regional Transit Accessibility
• Modify/enhance SCAGs regional model to reflect
  these intrazonal changes

3
How Blueprint Would Affect Travel and VMT
Production

• Characteristic Effects

Macro Level

• Better jobs/housing balance
• Improved regional transit
• Intensified growth in centers corridors

• Shorter commute trips
• More trips by transit
• More work destinations where auto not required

Micro Level

• Higher densities
• Mixture of uses
• Pedestrian friendly design
• Regional transit accessibility

• Fewer vehicles owned
• More travel to nearby non- work attractions
• More walk trips, short car trips

4
Analysis Focus Tools

• Macro Level
• TAZ to TAZ
• Primarily commute travel
• Apply regional 4-step travel forecasting model
• Micro Level
• Intra-zonal
• Primarily non-work travel
• Apply 4Ds procedure

5
Corroboration of Work vs. Non-Work Travel
Separation

• Solimar South Bay Cities research found people
  who live in mixed-use centers
• Make a high percent of their non-work trips to
  neighborhood center
• A high percentage of neighborhood center trips
  are by walk or bike
• Result is virtually independent of commuting
  behavior most still drive long distances to
  work place

6
4Ds Modeling Approaches Considered

• Systematic Changes to SCAG Model
• Trip generation, distribution, mode choice
  sensitive to land use
• Recalibrate trip tables to reflect change in
  average trip length
• Post-Processor Approach
• Replicate models of household vehicle ownership
  and VMT developed in Baltimore with SCAG data
• Use models to factor first stage VMT estimates
  from SCAG model to reflect 4Ds properties

7
Development of 4Ds Models

• SCAGs 2001 regional household travel survey
  trip rates, O/D, vehicles, socioeconomic
  characteristics
• SCAG regional travel model outputs modal travel
  times, accessibility
• GIS Tools calculate measures of mix and
  walkability
• Dunn Bradstreet data development of walk
  opportunities index

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Land Use Mix
¼ mile radius buffer
Where Pj proportion of land in the Jth use
type The index varies from 0 to 1, with 1
denoting ideal balance (all distinct land uses
occur in equal proportions)
SCAGs Land Use data at parcel level -- not
necessary to create cells with average land use
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Walk Opportunities Index
Opportunities å Wi Dij
Where Wi is the value of an opportunity within
walking distance (1/4 mile) of the household
(values range from -1 to 1) Dij is the walk
distance from the household to the opportunity
using the street grid
10
Household Vehicle Ownership VMT Models for SCAG
Region
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Post-Processor Approach

• 1. Run SCAG model on primary scenarios 2035
  Baseline 2035 Blueprint
• 2. Ascertain VMT and Work vs. Non-Work split for
  each TAZ
• 3. Apply 4Ds regression models to each TAZ to
  calculate VMT rates attributable to detailed land
  use design within TAZ
• 4. Develop TAZ adjustment factors for Non-Work
  VMT, use to factor initial SCAG model estimate

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Estimating 4Ds Effects Focus on Non-Work VMT
SCAG Regional Model
SCAG Regional Model
Predicted VMT (Baseline)
Predicted VMT (Scenario)
Predicted HBW VMT for TAZ x
Non-work VMT for TAZ x Total - HBW
Predicted HBW VMT for TAZ x
Non-work VMT for TAZ x Total - HBW
Focus of adjustment for 4Ds
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Application to Forecasting
Depiction of Land Use in Future Scenarios
5-acre Grid Cell
TAZ Boundary
14
Look-Up Table Default Values
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Determining Influence of Land Use in TAZ
Default 4Ds values weighted by households
Look-Up Table LU Mix (by type) Walk Opportunities
(by type)
Land use type j Quantity ( HHs)
Avg LU MixTAZ ?j (HHsj LU Mixj )
Total HHs
16
Estimating 4Ds Effects within a TAZ Based on Grid
Cells
Baseline TAZ
Scenario TAZ
Grid cells that have changed land use definition
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Estimating 4Ds Effects within a TAZ (only
necessary to compute for TAZs that have changed)
Grid Cells
Households
Base
Blueprint
Base
Blueprint
LU Mix
WalkOpp
Development Type
1
Downtown Ctr
0.655
5000
2
Downtown Res
0.622
10000
3
City Center
0
3
0
20
0.981
10000
4
City Res
0
8
0
50
0.659
7500
5
Town Center
0.865
6000
6
Town Res
9
4
40
17
0.181
500
7
City Neighborhood
0.181
500
8
Residential Sub
0.000
0
9
Large Lot
0.000
0
10
Rural Cluster
0.000
0
11
Activity Center
0.909
5000
12
Transit Station
0.547
5000
13
Transit Corridor
0.352
2500
14
Main Street
0.613
8000
15
Office Park
4
0
0
0
0.000
0
16
Industrial
0.000
0
17
Highway Commercial
2
0
15
0
0.048
1000
Totals
15
15
55
87
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Estimating 4Ds Effects within a TAZ (cont.)
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Making the 4Ds VMT Adjustment
Predicted VMT (Baseline)
Predicted VMT (Scenario)
Predicted HBW VMT for TAZ x
Non-work VMT for TAZ x Total - HBW
Predicted HBW VMT for TAZ x
Non-work VMT for TAZ x Total - HBW
Apply 4Ds Adjustment Factor (e.g., 67)
Adjusted Non Work VMT for TAZ x
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Reassembly and Comparison
Baseline
Scenario
Predicted HBW VMT for TAZ x
Non-work VMT for TAZ x Total - HBW
Predicted HBW VMT for TAZ x
Adjusted Non Work VMT for TAZ x
Total VMT (Baseline)
Total VMT (Adjusted)

• Impact Comparisons
• TAZ vs. TAZ
• All Blueprint TAZs
• All Non-BP TAZs
• Scenario vs. Base
• Scenario vs. Scenario

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Status and Next Steps

• Still dealing with unexpected delays in receipt
  of baseline grid cell and regional model output
  information
• Currently running test application for select
  counties -- examine reasonableness
• Apply to all counties for baseline and each
  scenario
• Use procedure in TransCAD to convert TAZ VMT
  adjustments back to link activity for air quality
  analysis