(Center Identification Number: 77801) This initiative is intended to further enhance TBEST capabilities in two specific areas. First, this effort will develop a methodology for disaggregating zonal social demographic data to the parcel level so that more precision in the specification of transit stop walk to access buffers can be developed.
Steve Polzin, Director, Mobility Research Program
Xuehao Chu, Senior Research Associate
Martin Catalá, Senior Research Associate
Center for Urban Transportation Research
University of South Florida
External Project Contact:
Florida Department of Transportation
I. Project Objective/Problem Statement
FDOT, in pursuit of its role to assist in providing public transportation services in Florida, has made a substantial research investment in a travel demand forecasting tool for public transportation known as Transit Boardings Estimation and Simulation Tool (TBEST). This tool is intended to help transit agencies comply with statutes as detailed in Public Transit 14-73.001, the rule governing the production of transit development plans.
Through the development process for TBEST the project team has identified additional opportunities to enhance and improve the model’s capabilities to further benefit transit properties. TBEST provides a set of interactive spatial tools for users to define and develop their transit route and stop configuration within TBEST. TBEST also incorporates several supporting databases for Florida transit properties that allow users to implement TBEST with modest effort. These include underlying street databases, census databases, InfoUSA employment databases, and precoded base transit networks.
This initiative is intended to further enhance TBEST capabilities in two specific areas. First, this effort will develop a methodology for disaggregating zonal social demographic data to the parcel level so that more precision in the specification of transit stop walk to access buffers can be developed. It is expected that through the use of parcel level residential land use information, zonal demographic data can be distributed such that a more precise understanding of walk-scale land use patterns can be captured by the model. This should enhance the stop level predictive capability of TBEST and enable an enhanced ability to evaluate policy issues associated with land-use development in proximity to transit.
Second, this initiative will include exploratory work to assess opportunities for enhancing the predictive capability of TBEST by improving the quality of data regarding trip attraction. A modest share of resources will be programmed to support the conceptual development of strategies for improving the data supporting trip attraction – both by exploring a better way to treat special generators such that a model variable can be created that relates to special generator trip attraction, and by an exploration of refined employment classification or zonal trip attraction as a means of providing a richer source of trip attraction data.
These two tasks are the top research priorities for ongoing TBEST enhancements.
Task 1: Project Management
This task will deal with on-going management activities of the project, preparing progress reports, and reviewing and editing final deliverables.
Task 2: Inventory Parcel Level Databases in Florida Counties
This task will review the parcel level databases for residential land use for Florida counties. This will involve identifying the parcel traits that can be used for distributing zonal demographic data. It is envisioned that factors such as dwelling unit size, number of bedrooms, and value among others might be the basis by which zonal data is attributed to the parcel level. The inventory will assess the nature and characteristics of the parcel level databases for all Florida counties that have fixed route transit services. Access to data, data format, and data variables will be among the characteristics that will be important in determining the ultimate methodology. Summary tables will be produced in the inventory should provide us to comment on the applicability to other counties that don’t currently have fixed route service within Florida and possibly provide some insight regarding how the methodology might be generalized for application beyond Florida.
Task 3: Zonal Demographic Disaggregation
This task will develop the formulas or strategies that will subsequently be programmed to distribute zonal demographic data to the parcel level. We will seek to develop a generalizable strategy applicable across the range of parcel level databases that exist in Florida. The goal will be to distribute residential household characteristics that are used in the modeling process to the parcel level.
Task 4: TBEST Software Modifications to Accommodate Parcel Level Data
This task will translate strategies developed in task three into TBEST software modifications. Similar to how TBEST can currently handle either InfoUSA address level employment data or zonal employment data, we envision software modifications that will let the user specify the development of parcel level data are continued reliance on homogenous zonal demographic assumptions. Gannet Fleming through their Geo-Decisions group has been a partner in the development of the model software and is scheduled to implement the logic and database changes developed in the project into the software. This will involve programming changes and working with the project team on the logic to insure compatibility with existing software and databases.
Task 5: TBEST Calibration for Parcel Level Data
This task will address the issue of the need to recalibrate or otherwise modify coefficients to reflect different residential buffer demographic conditions that will be expected with parcel level allocation of residential population. It is our expectation that the distribution of the zonal population based on parcel characteristics will result in walk access buffers with higher total residential population as we anticipate a natural clustering of residential activity in the vicinity of bus stops due to the probability that transit planners would attempt to locate bus stops in proximity to concentrations of residential activity or possible. If parcel level allocation does produce meaningfully different bus stop buffer demographics it will be necessary to recalibrate or modify the model’s calibration. The project team will assess and implement the appropriate strategy based on the magnitude of the impact of using parcel level data.
Task 6: TBEST Guidance Update and Activity Documentation Memorandum
This task will update the TBEST users’ manual and training materials to reflect the changes. In addition, a Technical Memorandum will document the technical activities carried out to accomplish these TBEST model changes.
Task 7: Exploration of Opportunities for Enhancing TBEST Predictive Capabilities
The greatest challenge to increasing the predictive capability of TBEST will be to increase the amount of information available to the model about the attractiveness of trip destinations. Home end trip productions at the household level vary relatively modestly and are known to be highly correlated with household characteristics such as income and vehicle availability that we have available to incorporate in our equations. However, at the destination end of a trip the only information that is used as a surrogate for trip attraction is the activity level expressed in terms of employment by type. The range of employment types is very modest and the relationship between employment type and trip attraction is highly variable. Many types of land uses that have attraction for trip ends have virtually no characteristic that can be integrated in the model absent designation as a special generator. The paragraphs below outline two possibilities that will be explored for improved trip attraction quantification.
Special generator enhancement
One improvement is to define special generators such that the characteristics of the generator are more highly correlated with trip attraction. One possible strategy for doing this would be to use ground count or other data on actual trip attraction at the special generator then debiting this from the trip attraction that would be expected based on the employment specified for that location. This incremental additional trip attraction, not currently captured by TBEST, could be introduced as a continuous variable for the special generators. It may even be possible to weight this trip attraction by its propensity to attract transit trips. For example one might weight activities that would be attractive to, for example lower income individuals, more highly. This concept would move from special generator as a dummy variable to special generators defined in terms of trip attraction which could be applied and measured discreetly for each location so designated in the system. For example larger schools would have higher values than smaller schools, etc.
Integration of trip attraction data
Another alternative strategy for dealing with improved forecasting would be to utilize trip attraction at the zonal level in lieu of employment. This concept would involve utilizing aggregate measures of trip attraction developed by existing regional models or other sources. These values for trip attraction would be imported into the TBEST zonal structure and use in lieu of employment in calculating measures of accessibility. Ultimately one could even choose to disaggregate trip attractions in proportion to parcel level development intensity and rely on TBEST to calculate aggregate attraction within the walk access buffer. This concept would enable the more refined and field validated trip attraction characteristics of regional models to be taken advantage of to improve the predictive capabilities of TBEST. This concept could offer improved transit forecasting and build a stronger relationship between regional roadway inclusive models and the TBEST modeling tool. This task will outline the options and data sources and make recommendations regarding the merits and level of effort required to implement the recommended changes.
Work not included in this scope of service is not to be performed and will not be subject to compensation by the Department.
Project deliverables will include quarterly progress reports, updates to the TBEST Users’ Manual and training materials, and two technical memorandums documenting the results of tasks one thru seven.
Progress reports will be submitted on a quarterly basis to the Research Center for processing. The first progress report will cover the activity that occurred in 90 following the issuance of the Notice to Proceed.
Reports should be submitted within 30 days of the end of the reporting period. Reports are due even if little or no progress has occurred (in which case, the report should explain delays and/or lack of progress). Progress reports should be sent in MS Word to Sandra Bell, firstname.lastname@example.org.
Progress reports will include the following information:
1. Contract Number, Work Order Number and Title
2. Work performed during the period being reported
3. Work to be performed in the following period
4. Anticipated modifications (i.e., to funding, schedule, or scope). This section is for reporting/informational purposes, not for officially requesting an amendment. Note: To request an amendment to a contract, the contractor must provide the project manager with the appropriate information (i.e., what is being requested with justification) in the required format. If the project manager concurs with the request, he/she shall forward it with his/her approval and commentary, as appropriate, to the Research Center for administrative review and processing (pending available funds, etc.)
5. A Progress Schedule (figures A, B, and C) updated to reflect activities for the period being reported.
Failure to submit progress reports in a timely manner may result in termination of the work order.
Draft Technical Reports
Draft versions of the two document deliverables, a Technical Memorandum covering the development of residential parcel level demographic data capabilities for TBEST and a Technical Memorandum proposing strategies for enhancing TBEST’s predictive capabilities by enhancing the data for modeling trip attractions will be edited for grammar, clarity, organization, and readability prior to submission to the Department for technical approval.
The draft technical reports will be submitted to Sandra Bell, email@example.com.
Once the draft final memorandums have been approved, CUTR shall prepare the final report. CUTR will deliver a minimum eight (8) copies of the final memorandums in MS Word on CD and one (1) unbound original, no later than the end date of the RPWO, to:
The Florida Department of Transportation
Research Center, MS 30
605 Suwannee Street
Tallahassee, FL 32399-0450
Each copy will be provided on a CD or DVD (i.e., for a total of eight disks). If the project manager requires additional copies, such provisions must be indicated in the scope.
The project manager will review the final report to insure that all issues identified for correction in the draft final report have been addressed.
The Final deliverables shall contain a page after the Technical Report Documentation Form that states the following:
1. The opinions, findings and conclusions expressed in this publication are those of the authors and not necessarily those of the State of Florida Department of Transportation, or the U.S. Department of Transportation.
2. Prepared in cooperation with the State of Florida Department of Transportation and the U.S. Department of Transportation.
Project Kickoff Meeting
A kick off meeting shall be scheduled to occur before any work begins. At a minimum, the project manager and the principal investigator will attend. The Research Center staff must be advised of the meeting and given the option to attend. Others parties may be invited as appropriate. The subject of the meeting will be to review and discuss the project’s tasks, schedule, milestones, deliverables, reporting requirements, and deployment plan.
Project Kickoff Meeting
The USF Research Financial Management office, as a final deliverable, will submit a project certification in accordance to the university compliance standards.
IV. Project Schedule
Start Date: October 2008 Expected End Date: June 2011
V. Project Budget
Salaries and Fringe 123,090.11
Fixed Price Sub Total 123,090.11
Indirect Cost (fixed price subtotal x 10%) 12,309.01
Total Fixed Price Amount 135,399.12
Total Project Cost: The project is cost reimbursable, and its price will not exceed $170,000.00.
No need for non-standard equipment is expected for conducting the proposed research.
One Tallahassee visit is programmed to achieve the project objectives. All travel shall be in accordance with Section 112.061 Florida Statutes, FDOT employees may not travel on research contracts.
VIII. Student Involvement
Use of graduate student(s) will be critical to this project. Specific involvement by students will support the data inventory task in the development of methods for disaggregating zonal data to the parcel level. In addition, it is envisioned that task seven will include student involvement, perhaps as part of a thesis or dissertation. The TBEST software programming partner, Gannet Flemming, will be a subcontractor in this project. Gannet Fleming through their Geo-Design group has been a partner in the development of the model software and is scheduled to implement the logic and database changes developed in the project into the software. This will involve programming changes and working with the project team on the logic to insure compatibility with existing software and databases. Project research staff are identified in the budget sheet with their levels of effort identified. Dr. Polzin will provide overall project coordination and strategic and theoretical guidance. Dr. Chu will provide methodological guidance and model calibration support. Mr. Catala will be responsible for the GIS applications elements of the scope. NCTR director Joel Volinski will provide oversight and overall quality control and dissemination of the final product. The graduate students will collect, assemble the parcel database information, conduct literature support on treatment strategies for generators (task 7) and geographic information systems (GIS) support.