Cover Image

Not for Sale

View/Hide Left Panel
Click for next page ( 70

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

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 69
THE SECRET IS IN THE SEGUE 57 a paper on the topic.3 The following points were covered (COTA). A system is also being developed at the Ohio in her presentation. Department of Transportation (ODOT), but is not yet operational. The initial system at MORPC was installed MORPC, in cooperation with the Licking County in 2004 and included one server and three worker com- Area Transportation Study, contracted with PB Consult, puters. A fourth worker computer was added in 2005. Inc. for the development of a new travel model in 2001. The worker computers are directly networked and are The MORPC area covers all of Franklin, Delaware, and isolated from the general MORPC network to make Licking counties and portions of Fairfield, Pickang, them less susceptible to viruses. This system is running a Madison, and Union counties. The area includes 1,805 32-bit Windows operating system and Java. internal and 72 external traffic assignment zones. The COTA purchased a system to support the North 2000 population was approximately 1.5 million. The Corridor Transit Project Draft Environmental Impact population is forecast to increase to 2 million by 2030. Statement. This system includes one server and four The new model is a disaggregate tour-based model worker stations all running 64-bit Windows and Java. applied with microsimulation of each individual house- The system being implemented at ODOT will include hold, person, or tour. The model was completed in 2004 one server and eight worker stations. It will use a dis- and further refined in 2005. The model consists of nine tributive version of Cube Voyager. separate linked models and other network processing The running times for the MORPC travel forecast- steps. The linked models include population synthesis, ing model for 2000 and 2030 vary by computer system. automobile ownership, daily activity pattern, joint tour The total running time for the core model for 2000 ranges generation, individual nonmandatory tour generation, from approximately 20 hours to 35 hours. The total run- tour destination choice, time-of-day choice, tour mode ning time for the core model for 2030 ranges from choice, and stops and trip mode choice. The core models approximately 26 hours to 48 hours. The 2000 model are applied in a disaggregate manner. includes 1.5 synthetic individuals making 2 million tours The model is applied with the microsimulation of and the 2030 model has 2 million synthetic individuals each household, person, or tour, mostly using Monte making 3 million tours. The COTA system, which uses Carlo realization of each possibility, estimated by the mod- 64-bit computing, provides the shortest running times. els and a random number series to determine which possi- Experience indicates that running antivirus software bility is chosen for that record. There are three global imposes a 15% penalty on the run time and that Win- feedback loops for consistency between highway travel dows will only allocate a maximum of 50% of memory times that are used as input to, and as forecast outputs of, to any one application. Planned future upgrades include the model. Cube is used as the main model application installing Cube on the COTA work stations and sending package and TP is used for network management, TP scripts to run in parallel on the work stations. assignment, external and commercial vehicle models, and other processing. After generating the networks and initial skims in TP+ and creating input files for a specific sce- PREPARING PARCEL-LEVEL INPUT DATA nario, the custom Java programs are executed to FOR THE ACTIVITY-BASED TRAVEL MODEL implement the tour-based microsimulation models. The IN SACRAMENTO microsimulation results are aggregated in a preassignment process or step, which also integrates the commercial and Bruce Griesenbeck external models to produce standard TP trip tables for four time periods, which are morning, midday, afternoon, Bruce Griesenbeck described the use of parcel-level data and night. Vehicles are assigned from the final trip table in the development of a new activity-based travel model with a multiclass equilibrium assignment utilizing 21 vol- for the Sacramento Area Council of Governments ume and delay functions by facility and area type for each (SACOG). He described the reasons for the use of parcel- of the four time periods. There are three classes of com- level data, the general structure of the new model, and mercial vehicles, four highway modes, and five transit the approaches for forecasting street pattern and transit modes. Nonmotorized modes are not assigned. accessibility data used in the model. The following points The MORPC travel forecasting model can cur- were covered in his presentation. rently run on three operational systems. One system is at PB Consult, one system is at MORPC, and one system A major focus at SACOG over the past few years was purchased by the Central Ohio Transit Authority has been on land use policy and land use planning. The policy board recently adopted a long-range land use vision 3 See Anderson, R. S., Z. Jiang, and C. Parasa. Hardware for the region, called the Blueprint. The vision provides a Requirements and Running Time for the Mid-Ohio Regional Planning basis for other land use planning activities in the region. It Commission Travel Forecasting Model. Volume 2, pp. 181184. promotes ideas related to urban containment and devel-