TMIPConnection
Issue 9, March 1999

The Travel Model Improvement Program Newsletter

The Travel Model Improvement Program is sponsored by:
U.S. Department of Transportation
Federal Highway Administration
Federal Transit Administration

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Travel Model Improvement Program Wins US DOT Award

The Travel Model Improvement Program staff received the “Find the Good and Praise It” award. This Department of Transportation award was instituted by Secretary Rodney Slater to recognize individuals and teams that have shown a commitment to fulfilling the Department's mission. The award name is from the line carved in the tombstone of Alex Haley, a DOT employee early in his career.

The award nomination was submitted by Joseph Canny, Deputy Assistant Secretary for Transportation Policy. In the nomination letter, Mr. Canny said of the TMIP program,

"TRANSIMS is a set of integrated analytical and simulation models and supporting databases. The TRANSIMS methods deal with individual behavioral units and proceed through several steps to estimate travel. TRANSIMS predicts trips for individual households, residents and vehicles rather than for zonal aggregations of households. TRANSIMS also predicts the movement of individual freight loads. A regional microsimulation executes the generated trips on the transportation network, modeling the individual vehicle interactions and predicting the transportation system performance. Motor vehicle emissions are estimated using traffic information produced by TRANSIMS.

During this period the Travel Model Improvement Program has produced an impressive record of accomplishments that include: completion of many research and development studies; development and teaching new courses; writing and distribution of newsletters; distribution of technical reports; development and maintenance of an informational web site; and sponsorship of a number of major user conferences.

This team represents one of the finest examples of interagency cooperation...”

The award was received by TMIP team members from the Office of the Secretary, Federal Highway Administration, Federal Transit Administration, the Bureau of Transportation Statistics, the Environmental Protection Agency, and the Texas Transportation Institute.

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TRANSIMS Travelogue – April 1999

TRANSIMS TRAVELOGUE describes current activities within the TRANSIMS project.

What is TRANSIMS?

The TRansportation ANalysis and SIMulation System (TRANSIMS) is one part of the multi-track Travel Model Improvement Program sponsored by the U.S. Department of Transportation, the Environmental Protection Agency, and the Department of Energy. Los Alamos National Laboratory is leading this major effort to develop the new, integrated transport- ation and air quality forecasting procedures necessary to satisfy the Intermodal Surface Transportation Efficiency Act (TEA-21) and the Clean Air Act and amendments.

TRANSIMS is a set of integrated analytical and simulation models and supporting databases. The TRANSIMS methods deal with individual behavioral units and proceed through several steps to estimate travel. TRANSIMS predicts trips for individual households, residents and vehicles rather than for zonal aggregations of households. TRANSIMS also predicts the movement of individual freight loads. A regional microsimulation executes the generated trips on the transportation network, modeling the individual vehicle interactions and predicting the transportation system performance. Motor vehicle emissions are estimated using traffic information produced by TRANSIMS.

TRANSIMS Depolyment Strategy

The goal of the TRANSIMS deployment strategy is to transition the TRANSIMS technology from Los Alamos research and development to commercial products for use by transportation planning agencies such as Metropolitan Planning Organizations. The strategic elements of TRANSIMS are defined customer needs, the TRANSIMS basic technology, the knowledge and know-how to apply the technology to the customer needs, the technical and financial constraints, and the product deployment process.

The basic TRANSIMS technology developed by Los Alamos National Laboratory is computer code called TRANSIMS-LANL.. That technology includes the TRANSIMS functional modules and the System Framework.

The TRANSIMS-LANL technology has many uses, but the current program was specifically created to target transportation planning applications.

To focus the development on those applications, the Laboratory is preparing case studies based on the Portland, Oregon transportation system. The case study preparation drives the underlying TRANSIMS-LANL research. Correspondingly, the TRANSIMS-LANL documentation also emphasizes the transportation planning application.

The Transportation Equity Act for the 21st Century (TEA-21) includes legislation to complete TRANSIMS-LANL, to develop a TRANSIMS commercial product, and to support early deployment of the TRANSIMS package to States, local governments, and Metropolitan Planning Organizations responsible for travel modeling. The available federal funds together with cost sharing by commercial developers will contribute to the deployment process success. Computer hardware and software technology advances also promote the assimilation of the TRANSIMS technology by the transportation community.

The product commercialization process includes licenses and contracts with vendors/developers to build "product shells." The TRANSIMS-LANL technology captured in the software will be repackaged in the product shells with enhancements to the user interface, the TRANSIMS modules, or other additions that make it more useable for specific markets. The first market to address is the transportation planning community as defined by the TEA-21 legislation.

In addition, research licenses will be available for universities to use TRANSIMS-LANL for research, development, evaluation, and demonstration purposes.

Sharing TRANSIMS with universities will spread the TRANSIMS methods and technology into university research, develop competencies in the TRANSIMS sciences, and help prepare tomorrow's transportation planners for exercising the TRANSIMS capability to its fullest.

TRANSIMS-LANL

The TRANSIMS-LANL version of TRANSIMS will be distributed under special license to attendees at the June 28-30 conference in Santa Fe (see other article in this newsletter). TRANSIMS-LANL will demonstrate all the TRANSIMS components. It includes the functional modules and the System Framework. The "System Framework" is the software, protocols, conventions, and data structures that support feed forward and feedback of information among the functional modules. The Framework includes a "Selector" module that specifies data to be distributed among the modules, transform- ations such as the addition of noise to the data values, and the sequences that comprise the feed forward and feed back paths.

TRANSIMS-LANL also will contain several networks. Some networks will demonstrate only the microsimulation. Others will require simplified synthetic population and activity generators, while others will be based on the full Los Alamos National Laboratory synthetic population generator and the activity generator developed by the National Institute of Statistical Sciences for the TRANSIMS project. Each TRANSIMS-LANL com- ponent will be documented. The components to be included in TRANSIMS-LANL are:

  1. System Framework
  2. Population synthesizer
  3. Activity generators
  4. Route planner
  5. Microsimulation
  6. Emission models
  7. Viewers
  8. Calibration networks and files

Selectors

A Selector is a System Framework component that controls the iteration process. Typically a TRANSIMS study involves iteration to move information between components such as the Activity Generator, Route Planner, and Travel Microsimulation. For example, iteration moves information about actual travel times from the Travel Microsimulation to the Route Planner. Iteration also is necessary to reach quasi-equilibrium among the nonlinear processes simulated by the TRANSIMS modules.

Different study designs involve different iteration schemes; hence different Selectors may be used in different studies. There is no single, "standard" Selector component. The figure illustrates where Selectors reside within the TRANSIMS framework.

At the beginning of each iteration, the iteration script controlling the current study typically invokes a Selector. (The script might use a different Selector for each iteration in a study.) When a Selector runs, it usually will:

  • Read information about the travelers from the Iteration Database.

    graphic showing a Selector running

  • Examine each traveler and decide whether to
  • regenerate activities using the Activity Generator,
  • choose a new route between existing activities using the Route Planner, or
  • retain existing activities and the planned route between them.
  • Write the selections made for each traveler into data files that can be read by the Activity Generator or Route Planner when they are executed.
  • Summarize the selections made and the current state of the system into a Selector Statistics data file.

After the Selector completes the selection process for all travelers, the Activity Generator, Route Planner, or Travel Microsimulation calculates the updated activity set, plan set, or microsimulation output files, respectively, according the Selector decisions. At the start of the next iteration the iteration script again will invoke a Selector.

Selector Input

The major input to the Selector is the Iteration Database. The Iteration Database contains a summary history of each traveler's attributes, expectations, and experiences during the iterations within a study. The Selector uses these data items to make its selection decisions. Attributes represent quasi-static information about travelers such as their age, income, gender, or profession. Expectations encompass information such as how long a traveler expects to travel between two activities based on the route between them generated by the Route Planner. Experiences comprise information extracted from detailed Travel Microsimulation output-for instance, the actual travel time realized in the microsimulation between two activities. The analyst may choose which attribute, expectation, and experience data resides in the Iteration Database to be readily available to the Selector for a particular study. Additional data from activity sets, plan sets, and microsimulation output also might be used by some Selector implementations.

Selector Output

The Selector has two principal outputs, Selector Statistics and Selection Choices. The Selection Choices files simply list the travelers that will be reassigned activities, replanned, resimulated, etc.; these files record the detailed Selector decisions. The Selector Statistics provide a basic summary of the choices a Selector makes, e.g., how many travelers are being replanned and distributions of the difference between expected travel times and experienced travel times for various traveler populations.

The TRANSIMS System Framework allows for countless variations on the selection process. For example, in some studies part of a Selector may run again after the Activity Generator or Route Planner completes its execution.

Then the Selector decides which activities or plans just generated will be accepted. Those not accepted are discarded and the previous activities or plans for travelers are retained. One also can design Selectors that will feed travelers to the Activity Generator or Route Planner one-by-one so that the Selector, Activity Generator, Route Planner, and Traffic Microsimulation all execute simultaneously with their coordination controlled by the Selector – this may increase the computational efficiency of a study and allow for new experimental designs with finely controlled iteration. A Selector might make additional choices such as:

  • which version of the Activity Generation, Route Planner, or Traffic Microsimulation will run during the present iteration,
  • whether transit schedules will be adjusted or vehicles added or removed from the transit fleet,
  • whether network characteristics such as traffic signal timing, congestion pricing, or roadway information signs will be altered,
  • which travelers will receive data from traffic information systems, or
  • whether to complete the study (i.e., end the iteration) because the iterations have converged sufficiently (or diverged).

The TRANSIMS-LANL software package contains several Selector implemenations for use in typical transportation planning studies. It is not difficult for analysts to write additional Selectors for their own specialized studies.

Further Information

For further information about the TRANSIMS program, please contact:

Dr. LaRon L. Smith
Los Alamos National Laboratory
Mail Stop F606
P.O. Box 1663
Los Alamos, New Mexico 87545
Phone: 505-665-1286
Fax: 505-665-5249
E-mail: llsmith@lanl.gov

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TRANSIMS Moves to Implementation

The Department of Transportation (DOT), in cooperation with the Environmental Protection Agency (EPA), has begun the TRANSIMS Early Deployment Plan (EDP). The EDP will transition the TRANSIMS focus from research and development to implementation and application. The EDP consists of three parallel efforts; completion of TRANSIMS research and development, development of user friendly software, and provision of support to a core group of local planning agencies to implement TRANSIMS.

Completion of Research and Development

The Los Alamos National Laboratory’s current effort focuses on completing the development of the basic TRANSIMS core package. The TRANSIMS core programs will be completed by December, 1999, and a case study demonstrating TRANSIMS capabilities will be completed during the summer of 2000. The case study will focus on Portland, Oregon and will simulate region wide travel on the entire Portland transportation system. Highway, transit and freight modes will be included.

User Friendly Software

While the Los Alamos National Laboratory will complete the TRANSIMS research and development, a contractor yet to be selected will develop user friendly TRANSIMS software. Organizations interested in participating in that effort should attend the Opportunity Forum to be held in Santa Fe, New Mexico, June 28-30 (see other article in this newsletter).

Local Planning Agency Participation

The EDP calls for implementing TRANSIMS in a wide variety of settings. To this end the USDOT will provide financial support to a small diverse group of local planning agencies to convert from existing travel demand procedures to TRANSIMS. To apply for this program, agencies will be asked to submit a statement of qualifications including technical capability, staffing and availability of matching funds. The solicitation will be issued in the Fall of 1999. From those technically qualified USDOT will select a diverse group to participate in the deployment program. More information on how to participate will be available at the TMIP IV conference in Philadelphia.

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TRANSIMS Opportunity Forum

A workshop on commercialization and deployment for TRANSIMS will be held in Santa Fe, New Mexico, June 28-30. Organizations interested in participating in commercialization and deployment are invited to attend. At the workshop participants will:

  • Meet with the Los Alamos National Laboratory TRANSIMS development team;
  • Receive a technical overview and additional details about TRANSIMS;
  • Learn about the TRANSIMS commercialization process;
  • Meet representatives of the potential customer base for TRANSIMS products to learn about and understand their needs and requirements;
  • Learn how TRANSIMS can be used in the transportation planning process;
  • Receive TRANSIMS software to assess and evaluate (a restricted software license agreement must be executed to receive this software); and
  • Meet other software developers to explore potential teaming relationships.

The workshop will be held at the La Fonda Hotel. Hard copy registration forms may be obtained by contacting Angelica Cisneros at 505-667-4698, 505-667-7530 (fax) or angelica@lanl.gov. The registration deadline is May 26, 1999. Hotel reservations at the La Fonda can be made by calling 800-523-5002 and asking for the “TRANSIMS Opportunity Forum.”

Larry Blair and Linda Rowton of Civilian and Industrial Technology Programs will host this workshop. For questions or additional information they can be reached at 505-665-3322, 505-665-2964 (fax), or lrowton@lanl.gov

For TRANSIMS technical information, contact Suzanne Watters, Technology and Safety Assessment Division at 505-665-0639, 505-665-5204 (fax) or swatters@lanl.gov.

Attendance and accommodations are limited and will be available on a first come, first served basis. Please register early and limit your attendees to two representatives from each organization. Attendees will be charged $200 per person to defer meeting costs.

Following the workshop interested organizations will have an opportunity to submit their qualifications and may be invited to respond to a Request for Proposal (RFP) to participate in the commercialization and deployment process. A preliminary request for an expression of interest and statement of qualifications will be posted on the following web site: http://bus.lanl.gov/bus5/vendor/solicitations/default.htm. That will be for information only and will be subject to change. Further information will be available at the June 28-30, 1999 workshop. A subsequent bidders conference is being planned for a later date at a place to be determined.

Bike-Ped Model

The Texas Transportation Institute (TTI) has developed bicycle and pedestrian travel forecasting procedures for the Texas Department of Transportation (TxDOT). Those procedures were developed with data collected in surveys in several of Texas cities. The TxDOT procedures are similar to other bicycle/pedestrian sketch planning models in that they rely on Census information at the tract level for trip generation. A simplified trip distribution procedure assigns the bicycle and pedestrian trips to a roadway or other travel corridors. The new procedures are tentatively scheduled for field testing later in 1999 in several Texas cities. If the field tests are successful, TxDOT hopes to use the demand forecasting procedures in their project development and design processes. Reports that document data collection and model development and a users manual are available from Maria Burke at TxDOT (512) 416-2703 or from Gordon Shunk (817) 462-0529 or Shawn Turner (979) 845-8829, both at TTI.

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What’s New on the TMIP Web Site?

  • Technical Report: Considering Land Use and Pricing in Metropolitan Transportation Planning, Federal Highway Administration (FHWA), U.S. Department of Transportation, November 1989 [Added 3/15/99]
  • A Least Total Cost Approach to Compare Infrastructure Alternatives, Patrick DeCorla-Souza, Brian Gardner, Jerry Everett & Michael Culp, Federal Highway Administration, 1997 [Added 3/10/99]
  • Abstract: Time-of-Day Modeling Procedures: State-of-the-Art, State-of-the Practice, DOT-T-99-01 [Added 2/5/99]
  • Abstract: The Dallas Case Study, DOT-T-99-04 [Added 2/5/99]
  • Abstract: Guidelines for Network Representation of Transit Access, State-of-the-Practice Summary, DOT- T-99-05 [Added 2/5/99]
  • Site Design & Travel Behavior: A Bibliography, Rebecca Ocken, 1000 Friends of Oregon, 1993 [Added 1/27/99]
  • Population Forecasting Methods: A Report on Forecasting and Estimating Methods, U.S. Department of Transportation Federal Highway Administration Bureau of Public Roads Urban Planning Division, Revised June 1964 [Added 1/22/99]
  • Assessing the Emissions and Fuel Consumption of Intelligent Transportation Systems (ITS), EPA's Office of Policy, Publication No. EPA-231-R-98-007 [Added 1/22/99]
  • Land Use/Transportation Scenario Testing: A Tool for the 1990s, Michael Replogle, prepared for presentation to Transportation Research Board 1993 Annual Meeting [Added 1/4/99]

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The New TMIP E-mail List

TMIP has a new mailing list. Well, it is the same mailing list, but we have a new service provider. OneList (http://groups.yahoo.com/) now hosts our mailing list. This new service is more reliable, user friendly and has many more options as compared to our previous service provider. Members can change their settings by visiting the OneList web site or by sending various e-mail messages. For example, a member can change his or her preferences to receive all of the messages in a digest format. Digest mode formats all of the e-mail messages each day in one long message rather than receiving a message every time one is sent to the list. Members can also set their preferences to "no mail" for vacations or extended business trips. This stops the user from receiving mail while away without having to unsubscribe before leaving and resubscribing after returning. Check out all of the options and be a part of some very interesting conversations. Sign up to the TMIP Mailing List by visiting http://groups.yahoo.com/subscribe/tmip/ or by sending a blank message to tmip-subscribe@onelist.com.

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New Publications

Time-of-Day Modeling Procedures: State-of-the- Art, State-of-the Practice, DOT-T-99-01

This report identifies commonly used, innovative methods and emerging methods to estimate time of day travel demands. Time of day factors can be determined through household/travel survey data, from on-board transit and intercept surveys, or twenty-four hour machine, transit, and truck counts. Time of day assignment can occur in four places in the modeling process: after trip assignment, between mode choice and assignment, between trip distribution and mode choice or between trip generation and trip distribution. Three innovative methods being used by MPOs and state agencies and discussed in this report are link-based peak spreading, trip-based peak spreading and system- wide peak spreading. The pros, cons, applicability, and data required for each are discussed. An emerging approach is a time choice component for the "four step" modeling process.

Land Use Compendium, DOT-T-99-03

The Federal Highway and Federal Transit Administrations have assembled three papers on land use: "A Technical Review of Urban Land Use - Transportation Models as Tools for Evaluating Vehicle Travel Reduction Strategies," "Review of Land Use Model and Recommended Model for DVRPC," and "Land Use and Travel Model Survey Data." The first paper provides a technical review of land use models and gives a state-of-the-practice review of the methods used by various MPOs. The second document provides information that can be used by agencies considering developing land use forecasting methodologies. The third paper summarizes the results of a survey of land use data collection in 35 MPOs.

Guidelines for Network Representation of Transit Access, State-of-the-Practice Summary, DOT-T- 99-05

Sophisticated travel models require complex strategies for network representations of transit access. This report addresses three main issues: transit access method is not uniform in a zone, transit riders do not necessarily use the park and ride at the location nearest them, and access method varies for each transit mode. The report describes procedures that have been successfully tested although every method is not applicable for every situation.

The Dallas Case Study, DOT-T-99-04

The report summarizes the TRANSIMS microsimulation application in Dallas, Texas. This case study simulated individual vehicles in a simulated transportation network and tracked their movements. The case study examined two different types of roadway improvements: adding a lane in each direction on a freeways and changing arterial street operations, intersections and capacity.

Information on these and other TMIP reports is available from Kim Fisher at 202-366-4054 or kim.fisher@fhwa.dot.gov.

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To subscribe to this free newsletter send an e-mail to TMIP@tamu.edu or contact Gary Thomas at (ph.) (979) 458-3263, (fax) (979) 845-6001, (mail) Gilchrist, Room 112, Texas Transportation Institute, Texas A&M University System, 3135 TAMU, College Station, TX 77843-3135