2010-01 Origin Destination Matrices

NCHRP 08-36
Proposed Project No. 2010-01
Research Statement
Guidebook on Determining Origin/Destination Matrices from Traffic Counts
The creation of origin/destination (OD) matrices from traffic counts (also known as
synthetic trip table estimation, origin/destination matrix estimation or ODME) has been
growing in popularity among transportation planners and traffic engineers because they
are able to replicate existing conditions better than traditional techniques. However,
these methods tend to be highly empirical and incorporate only a minimal amount of
travel behavior theory. Driving forces for this methodology are:
Newer traffic operational models that assign OD tables to networks to obtain
turning movements at intersections;
Recent interest in short term (less than 5 years) travel forecast for which an OD
table is likely to be fairly stable;
Recent interest in multiclass travel models, where there is a deficiency of
behavioral data about one or more vehicle classes;
Larger-scale models (such as statewide travel forecasting models) which may
contain rural areas for which behavioral information is absent.
Lack of current travel survey data or reliable survey data at sub-regional
geographic levels.
However, these techniques have had their detractors. Methods often violate statistical
standards by having more variables than data items. There are no accepted standards of
how good or badly the OD table should match count data. There are many different
mathematical formulations that each gives a different answer from the same data. There
is little guidance as to how the “seed” (the beginning point for the statistical fit) OD table
should be constructed for any given problem. Many of the methods are poorly
documented. The lack of a behavioral foundation and the static nature of the travel
matrices thus produced make them unsuited for analyzing situations where land use or
the transportation network changes significantly, yet no guidance on this limitation exists.
There is a need for clear technical guidelines on the application and use of
Origin/Destination Matrix Estimation. This proposed guidebook will provide knowledge
to practitioners who may be interested in applying such methods and give them guidance
as to their advantages and limitations.
This proposed guidebook will also:
1. Review current practice in creating OD tables from traffic counts, both in the US
and abroad.
2. Survey agencies and consulting firms to improve the profession’s understanding
of the purposes for which ODME is used.
3. Review academic and professional literature on methods for creating OD tables
from traffic counts.
4. .Describe appropriate methods for determining the number, location, consistency
and confidence levels of traffic counts for ODME.
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NCHRP 08-36
Proposed Project No. 2010-01
5. Describe appropriate methods for developing the seed matrix and other potential
inputs to the ODME process.
6. Document use of ODME in case studies, noting technical challenges encountered
and QA/QC procedures used to develop the synthetic trip tables.
7. Provide guidance on appropriate situations for ODME techniques versus the use
of behaviorally based travel demand forecasting techniques.
8. Describe specific techniques for predicting future travel demand based upon
ODME based OD tables.
Cost: $100,000
Submitted by:
Alan Horowitz
Professor, University of Wisconsin -- Milwaukee
Gregory Giaimo, PE
Transportation Engineer, Ohio Department of Transportation
Rob Bostrom, PE
National Practice Leader for Travel Demand Modeling, Wilbur Smith Associates
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