Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 76
64 I N N O VAT I O N S I N T R AV E L D E M A N D M O D E L I N G , V O L U M E 1
NCHRP, a consortium of metropolitan planning organi- there have been many indications from conference
zations and state departments of transportation, or pos- speakers that existing practices are inadequate. Bill
sibly software firms take the lead in helping bring a Woodford's session on FTA-sponsored research touched
central focus to model development, testing, and deploy- on problems associated with existing traffic assignment
ment. Practitioners, academics, and consultants all need procedures. Martin Wachs's presentation on the results
to be involved in the process. of a recent state-of-the-practice survey indicated that
I think the lack of stochastic models is also an obsta- many MPOs are behind the curve with respect to rea-
cle, as is the need for techniques to conduct risk analyses. sonable modeling practice. How can we realistically
At the Puget Sound Regional Council, we are just begin- bring advanced methods into practice when we are not
ning a 1-year testing phase of the UrbanSim land use doing an adequate job with existing methods?
model. We have an enhanced four-step model that is The TPB adheres to a multitrack model development
being used to test pricing and high-occupancy toll lane process. We have an applications track, which focuses on
alternatives. It appears to be working well. We are also short-term improvements to existing methods, and we
conducting a new 2-day travel diary survey. We may try also have a methods development track, which focuses
microsimulation tour-based modeling in 2 or 3 years. on the development of more advanced models and tech-
Along with the 2-day travel survey, we have a major niques. The methods track activities proceed in parallel
problem of converting all our data from the standard with the applications track so that advanced methods
industrial classification system to the North American may be phased in when deemed appropriate. If resources
Industrial Classification System. We are compiling a are available, I would strongly encourage MPOs to
2006 base year for UrbanSim and we will recalibrate our adopt a similar approach. We feel the "dual track"
travel model to 2006. We would also like to add a approach is reasonable for incrementally phasing
regionwide dynamic traffic assignment model or a sketch improvements into production when the improvements
accessibility calculator, if these tools are developed. are ready. We also believe in the development of empiri-
cally based models and the use of locally collected data.
Ronald Milone One obstacle to moving advanced methods into prac-
tice is the grueling production schedule faced by many
T hank you for inviting me to offer comments on what
it will take to bring advanced travel modeling meth-
ods into practice. This is certainly an important and timely
MPOs, which includes periodic plan updates, air quality
state implementation plan and conformity work, and
project planning studies. Given this busy schedule, I feel
conference, and TRB is to be commended for bringing us that there must be a firm understanding about the
all together. Both the practitioners and the research com- amount of time and resources that will be required to
munity have a great deal to gain by working more closely develop new methods. In order to secure time and
together in the coming years. Earlier, Frank Koppelman resources, our staff and board also need to understand
made the interesting comment that many of the groups how the advanced methods are superior to existing
involved in the planning process are increasingly talking methods.
past each other and not really listening to each other. I Another obstacle to moving forward is the lack of
think the same phenomenon has been occurring between observed data. Several speakers highlighted both the lack
practitioners and researchers. This conference has helped of data and the limitations of existing data used in model
to close the gap between research and practice, and that is development work. It is important that the data needed
needed for progress in the travel forecasting field. to calibrate and validate advanced methods are clearly
The Metropolitan Washington Council of Govern- understood. I would submit that understanding observed
ments Transportation Planning Board (TPB) employs a data and input data is just as important as understanding
conventional four-step travel demand model that is typi- the model itself. There was a great deal of discussion at
cal of such models applied at most metropolitan plan- the conference about what makes one model "better"
ning organizations (MPOs) around the country. We are than another model. I do not think that is a useful dis-
working hard to address a wide variety of complex trans- cussion. I would submit that the "best" model is the
portation issues in the capital region, and we are increas- model that is calibrated with quality data and is driven
ingly pushing the travel model to go beyond what it was by quality inputs: accurate land use forecasts, accurate
originally designed to do. In addition, our modeling network coding, and accurate policy assumptions.
process has received a great deal of technical scrutiny, Finally, the advanced methods need to be fully trans-
particularly by environmental groups. As a result, much parent to practitioners before they are used in applica-
time has been spent examining and refining our methods tion. Practitioners presently understand the four-step
used in application. model very well. They know how to develop four-step
The motivation of this conference is to facilitate the models and how to interpret results. They understand
implementation of advanced methods into practice. Yet, the limitations of the four-step approach. As advanced
