Title – Data Transferability for modeling
Background
Recently, research was undertaken to empirically test the transferability of activity-based (AB)
models between regions. Using 2008-2009 National Household Travel Survey data, AB models
are estimated simultaneously for six regions, in California and Florida. Statistical tests are
applied to identify regional differences in the models. Tests reject the hypothesis that models
based on data from different regions are identical, but most individual coefficients are not
significantly different from region to region. There is evidence of model similarity among
regions, but small sample sizes prevent strong conclusions. Estimability improves with larger
survey samples; 6,000 households provide much better information for estimating coefficients
than samples of size 2,500 or less. Thus, although estimation of models using a large local
sample is best, it is better to transfer models built using a large sample from a similar region
than to estimate new models using a much smaller local sample. However, local survey data is
needed for calibrating components of the model. Four specific transferability hypotheses are
tested, with results as follows: (1) Supported: Variables that apply to population segments
defined by characteristics of individuals or their situational context (segment-specific variables)
are more transferable than variables that apply to all individuals. (2) Not supported: Segmentspecific variables are more transferable than alternative-specific constants. (3) Strongly
supported: Models that deal with activity generation and scheduling are more transferable than
models that deal with mode choice and location choice. (4) Inconclusive: Models for different
regions within the same state are more transferable than models from different states. This
work should be further pursued.
Statement of Urgency:
State DOTs and MPOs/COGs of all sizes would benefit from such practical research, as public
funds for data collection and model development are shrinking, survey response rates are
declining (especially in the case of hard to reach populations).
Project Objective
Explore the supported hypothesis that variables that apply to population segments defined by
characteristics of individuals or their situational context (segment-specific variables) are more
transferable than variables that apply to all individuals. Define the similarities in regions required
for data transferability; define temporal similarities required for data transferability, such as similarities
in terms of growth patterns, socio-demographic make-up, etc.
Cost
$80,000
Time Required
12 months
Name Affiliation and Contact information of Submitter:
Guy Rousseau, Atlanta Regional Council
Shimon Israel, MTC
David Oury, MTC
Title: Data Fusion 2
Background
All of our data is still not quite enough to perform the in depth analyses required for modeling,
planning and performance measurement. Each data source provides a piece of the puzzle but
marrying the sources to get a robust picture takes art, finesse and guidance. One of the issues
we encounter frequently is different data are from different year. How we should “fuse” this
data together? Sometimes we have multiple sources of same or similar information, Should we
fuse the data or just choose one?
Statement of Urgency
As Census data is stretched ever thinner to cover small geographies and large, collected at
about half the sample size of the now retired Census Long Form, We need a way to “fuse”
Census data with other data:
Project Objective
-- Agencies have access to Census data such as CTPP flows, LEHD flows, PUMS, and others.
-- develop guidance on how to “fuse” the different Census products into something useful for
specific planning/forecasting purposes.
-- develop guidance on how to “enhance” the usefulness of the Census products through
“fusing” with non-Census sources, both public and private.
-- develop guidance to “enhance” the usefulness of non-Census data sources, through
incorporation of Census data. For example how Census data is used to expand household
surveys.
Cost
$60,000
Time Required
12 months
Name Affiliation and Contact information of Submitter:
Erik Sabina, CDOT
Juyin Chen, VDOT
Phil Mescher, IADOT
Maryann Waldinger, COMPASS
Guy Rousseau, Atlanta Regional Council
Ken Cervenka, FTA