STAFF REPORT. MEETING DATE: July 3, 2008 AGENDA ITEM: 7

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1 STAFF REPORT SUBJECT: Travel Models MEETING DATE: July 3, 2008 AGENDA ITEM: 7 RECOMMENDATION: Receive information on status of travel model development in Santa Barbara County and review factors to achieve consistency between SBCAG regional model and local models. STAFF CONTACT: William F. Yim and Michael G. Powers SUMMARY: For the last few months, several local jurisdictions have been either developing or updating their local travel models. The Cities of Lompoc and Santa Barbara are developing new models. The Santa Maria/Orcutt and Santa Ynez Valley Models are being updated with more recent software platforms. Local models provide local jurisdictions technical capabilities that are needed for local traffic impacts and environmental analysis, but these local models also raise consistency issues with the SBCAG regional model. This staff report provides a status report on travel models used in Santa Barbara County and attempts to clarify the relationship between the regional model and local models and discusses the factors affecting the consistency between them. Recommendations are provided toward achieving model consistency through a peer review process and creation of a Santa Barbara County Model Users Group to promote cooperation and collaboration in achieving model consistency process. DISCUSSION: The report provides a status report on travel models used by jurisdictions in the county and describes the relationship between the SBCAG regional model and local models. The objective of this report is to improve consistency between the regional and local models.

2 Santa Barbara County Travel Model Development The SBCAG Travel Demand Model: As the Metropolitan Planning Organization for the County of Santa Barbara, SBCAG maintains a countywide regional travel model to forecast changes in trips and traffic growth, assess demand for roadway and intersection improvements, evaluate land use alternatives and transportation control measures (TCMs), and, determine consistency between transportation and air quality plans. Between 2004 and 2007, the SBCAG travel model was improved for application in the 101 In-Motion Program and the update of the 2008 Regional Transportation Plan (2008RTP). In May this year, the SBCAG Expanded Model was also provided to Caltrans District 5 for use in analyzing and evaluating state highway improvements and monitoring projects including the Corridor System Improvement Program (CSMP), the Congestion Management Improvement Account (CMIA) Program, and the South Coast Highway 101 HOV project. Local Travel Demand Models: For the last few months, several local jurisdictions have been either developing or updating their travel demand models. The City of Lompoc initiated development of a citywide travel model in March 2008 as part of the Lompoc General Plan Update. The City of Santa Barbara hired a team of consultants to assist the City in the development of a citywide model as part of the Santa Barbara General Plan Update (Plan Santa Barbara) and the accompanying Environmental Impact Report (EIR). In the Santa Maria area, PVT Vision, a European transportation-consulting firm, in cooperation with the Associated Transportation Engineers (ATE) is converting the Santa Maria/Orcutt Travel Model from TModel2 to VISUM for purposes of testing out buildout conditions of the Santa Maria General Plan and the Orcutt Community Plan. The updated model will be used by the County of Santa Barbara and the City of Santa Maria for traffic impact and environmental studies for the area. The County s Santa Ynez Valley Model is also undergoing a similar model update process by PTV Vision. In addition, the City of Goleta travel model was updated by Dowling Associates two years ago. In the next year or so, a majority of the cities and unincorporated County subareas within this county will achieve improved capability of conducting more detailed sub-area travel forecasting and analysis. Table 1 summarizes the travel models that are currently being applied within Santa Barbara County. Model Consistency Issues Local models provide local jurisdictions technical capabilities that are needed to examine transportation impacts associated with land use decisions including environmental analysis, but these local models also raise consistency issues with the SBCAG regional model. For example: What are the primarily functions of these local models and how are they related to the regional model? Why is consistency between regional and local models important? Is the review process (which allows local models to be reviewed by SBCAG, as required by the federal and state legislation) being utilized? What are the factors needed for achieving model consistency between regional and local models? What are the input and output exchanges between local and regional travel models? How can the regional model be improved by local models and vice versa? 2

3 Applications of Travel Demand Models Travel demand forecasting is a major part of the transportation planning process. It involves forecasting socioeconomic and land use change and estimating the transportation impacts that various policies and programs will have on travel in an urban area. Travel demand models provide detailed information, such as traffic volumes, bus patronage, and turning movements to be used by engineers and planners in their roadway and intersection designs. Travel forecasts predict the number of vehicle trips on a future freeway or the number of passengers on a new express bus service. Travel models are used as a tool in addressing many technical and policy related issues in transportation planning such as the development of assessment fee programs. They may predict the amount of reduction in auto use that would occur in response to a new policy changing fees on central-area parking. As an example, one of the objectives of the Santa Barbara City Model currently under development is to examine the impact of parking pricing policy changes in downtown Santa Barbara. Regional Models and Local Models Under federal law, metropolitan planning organizations (MPOs) such as SBCAG are charged with developing transportation plans and programs to accommodate mobility needs for persons and goods within our region. Part of our responsibilities is to meet the need for development and maintenance of a viable regional travel model for purposes of providing long-term countywide and sub-regional travel forecasts. Regional models are used to predict transit ridership and benefits as a result of implementing various transportation demand management alternatives. Because of the regional nature of these models, most MPO models are socioeconomic databased, employing factors such as population, housing, income and employment from adopted regional growth forecast (RGF). Local models used by local agencies are subarea models. They are used primarily for local traffic impact studies to meet intersection level of service standards. These models have more refined traffic analysis zones (TAZs) and networks in order to identify local circulation and projected related impacts. Local models are generally land use databased, using various land use categories from local general plans and square footages of commercial developments. One of their primary uses is to provide possible suggestions for general plan policy development and assessment of environmental impacts resulting from general plan implementation. The model outcomes are then used to inform decision-makers regarding future land use strategies, detailed environmental studies and transportation infrastructure design. For the last several years, travel models have become more important in providing insights for elected officials in addressing policy-driven questions such as alternative modes of transportation, land use-transportation connections, smart growth, and parking pricing, etc. As an example, the new Santa Barbara City Model currently under development aims to examine various land use policy alternatives to address land use and transportation interactions. Regional models and local models have a close relationship. A regional model such as the SBCAG model provides coverage not only the entire Santa Barbara County, but also its two neighbors, SLO and Ventura Counties. Geographically, the SBCAG model provides a macrolevel perspective with larger traffic analysis zones. Its countywide network incorporates roadway classifications from freeway to major collectors. Because of its regional coverage, the SBCAG model is able to provide detailed inter-county, inter-regional and inter-community travel information. The origin-destination matrices by region and future traffic forecasts on state and inter-regional routes are particularly important for decision makers from the county and local elected officials. Local models however have a finer grained level of geography within a city boundary, focusing on providing local circulation and traffic impact information within a city boundary. 3

4 Legislative Requirements for Consistency between Regional and Local Models The federal government, state transportation agencies, and MPOs have historically shared responsibilities for developing regional travel demand models. At the national level, the Clean Air Act, the National Environmental Policy Act (NEPA), and the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) require MPOs to have a robust travel forecasting process in place. The Federal Transit Administration (FTA) and Federal Highway Administration (FHWA) jointly conduct a certification of each transportation management area (TMA) every four years to ensure the adequacy of the transportation planning process. This certification process includes a review of the travel forecasting methods, which includes measures of travel demand modeling capability, funding, and peer review of travel forecasting methods and documentation. SBCAG had this review this past Spring. State law requires local models to be developed for consistency with regional models. The following is from the California Government Code Section 65089(c): California requires MPOs and urban counties to develop and maintain travel models in consultation with the regional agency, cities, and the county, to develop a uniform data base on traffic impacts for use in a countywide transportation computer model and shall approve transportation computer models of specific areas within the county that will be used by local jurisdictions to determine the quantitative impacts of development on the circulation system that are based on the countywide model and standardized modeling assumptions and conventions. The computer models shall be consistent with the modeling methodology adopted by the regional planning agency. The databases used in the models shall be consistent with the databases used by the regional planning agency. Where the regional agency has jurisdiction over two or more counties, the data bases used by the agency shall be consistent with the databases used by the regional agency. Congestion Management Program Requirements In addition to national and state regulations for model consistency, MPOs are required to develop and maintain regional travel models for use in the Congestion Management Program (CMP) for their responsible counties. As the Congestion Management Agency for Santa Barbara County, SBCAG has responsibilities to develop and maintain a regional travel model to coordinate transportation planning, funding and other activities in the CMP. When sub-regional models are developed, state legislation requires that the Congestion Management Agency to review transportation computer models of specific areas to ensure that potential issues on regional highways and arterials are being adequately addressed. Travel model review policies have been developed by SBCAG for the CMP includes a general review of assumptions, geography, input/output data, and study results. (See attachment - Appendix F. CMP, Biennial Update, November 2003). Within the CMP context, SBCAG and local jurisdictions in this county are already collaborating in the following areas: Addressing CMP legislative objectives CMP performance assessment and monitoring Regionally significant Intersection LOS analysis Land use and building permit submittal by locals Peer Review Process In the past, peer reviews for local models to assess their consistency with the SBCAG model were conducted on a voluntary basis - either as part of the model development process or at the request of SBCAG. However, when local models have not been submitted to SBCAG for review, recent experiences have resulted in SBCAG reviewing local travel model parameters when project-related environmental documents are issued, which, in many instances, is too late 4

5 since the model has already been developed or updated. This could be problematic if there are significant differences between the regional and local models. Most recently, local model development opportunities such as the Lompoc City Model and the Santa Barbara City Model are a major step for locals to attain new modeling capabilities. This also presents an opportunity for a joint effort between SBCAG and local agencies to achieve model consistency within this county. In view of the federal and state legislation for model consistency requirements, staff believes that a formal process of inter-agency peer review process would lead to improved consistency between regional and local travel models. Consistency Issues between Regional and Local Models In view of the model consistency requirements and close relationships between regional and local models, the following section examines factors for which local models should strive to be consistent with the SBCAG model. They are: Geography and network External Traffic Regional Growth Forecast and Model Database Trip Rates Software Platforms and Capabilities Each factor is discussed below. Table 2 provides description of input and output interactions between the SBCAG regional Model and local models. Geography and network: Issue: The uniform geographical base for any travel demand model data is the traffic analysis zones (TAZs). TAZs are a set of homogeneous geographic zones which are delineated based on socioeconomic and land uses for purposes of transportation modeling. Regional models generally have larger but fewer TAZs for purposes of modeling the entire geographical region. Since 1991, the U.S. Census Bureau in cooperation with all MPOs, updated the geography for the entire nation into Census TAZs for consistency. This Census TAZ program was updated in 2001 and will be updated in the near future in preparation of the 2010 Census. Regional model TAZs also include sub-regional TAZs, but they are usually at a coarser level. Each TAZ in a sub-regional may include an area of several street blocks. Exhibit 1 shows a comparison between the Goleta Model and the SBCAG Model TAZs. The SBCAG model network was developed using the U.S. Topologically Integrated Geographic Encoding and Referencing database (TIGER/Line) and refined with roadway centerline aerial imageries. Local models are usually city or subarea models which have fine-grained TAZs within each city boundary domain. For example, local model TAZs in a downtown Central Business District (CBD) can be down to city street blocks. Furthermore, local models have finer networks which may extend to all local streets within a neighborhood in order to allow traffic and circulation patterns on sub-areas be analyzed. Recommendations: In general, local model TAZs should be subsets of the regional TAZs for consistency with Census data and the federal requirements. In Santa Barbara County, local model TAZs and networks are primarily based on the SBCAG model, for example, the Goleta and Santa Maria/Orcutt models. Staff is particularly appreciative of 5

6 the fact that the recent model development for the Cities of Santa Barbara and Lompoc actually requested the SBCAG model information for consistency. The SBCAG model TAZs are expected to be updated again in the near future (associated with the 2010 census), it is recommended that TAZs developed for local models would need to be reviewed by SBCAG for consistency with the SBCAG model on a timely basis. In addition, local model networks should also be reviewed for consistency with the regional network up to the collector level. Exhibit 1: Goleta Model TAZs vs. SBCAG Model TAZs External Traffic Issue: External trips are trips outside a model domain. Local model networks are part of the regional model network. Traffic at external stations of the city boundary, for example, at freeway and arterial entry and exit points of the local domain, must be consistent with the SBCAG regional model in order that travel forecasts are consistent with the regional model. External traffic feeding into local models from the SBCAG model would ensure the necessary consistency with local model output and traffic circulation within a subarea. Recommendation: Traffic forecasts at external stations for local models are recommended to employ regional model forecasts as part of their model input and validation. Regional Growth Forecast and Model Database: Issue: The socioeconomic data (population, housing, income, and employment) employed by regional models generally come from adopted regional growth forecasts. Local models generally employ land use data from their respective general plans. Local model land use databases are often unique and sometimes specifically tailored because their designations are often influenced by local policy decisions. These land use databases may not necessarily correlate with socioeconomic trends nor are they 6

7 consistent between adjacent jurisdictions. In addition, ongoing land use updates from general plans and periodic revisions of regional growth forecasts for regional models often present additional challenges in database consistency between regional and local models. Current database of the SBCAG Expanded Model was based on a revised version of the 2002RGF. In September 2007, the new 2007RGF was adopted with long range growth forecasts projected to the year In the next few months, staff will be updating the SBCAG model database based on the 2007RGF. Recommendations: It is recognized that a universal conversion table applicable for the entire county might be difficult to develop because of the varying land use categories and the different economic environments among various jurisdictions. One option is to develop a broad database conversion process whereby the similar land use databases employed by local models could yield as close as possible the control totals of the regional model. For example, residential land use categories would be converted to occupied dwelling units, and non-residential land uses would be converted to employment totals with ranges of values reflecting variations in occupancy rates and land use categories. This option would allow a two-way street comparison enhancing the aggregation of socioeconomic data for comparison. It is recommended that local models should incorporate a broad database conversion spreadsheet as part of the local model development process for review by SBCAG staff to ensure database consistency to the extent possible. Trip Rates Issue: Trip rates employed by local models primarily come two sources: 1/ The Institute of Transportation Engineers (ITE) Trip Generation Manual by land use categories, and 2/ local or other area traffic impact studies similar to the local situation. The trip rates from the latter often vary from city to city. For example, tourist destinations such as Solvang, Carpinteria, or Santa Barbara could have unique trip rates. Conversely, trip rates in the SBCAG model came from the Caltrans Household Survey for Santa Barbara County. These rates, by trip purpose, are then cross-classified by household size and income groups. These two approaches in trip generation between regional and local models could yield different model results simply because of the fundamental differences in socioeconomic and land use databases. Recommendations: The differences in trip rates employed between regional models and local model have always been and will continue to be an issue for model consistency. However, as part of the peer review process, local agencies are obligated to involve SBCAG as part of the model development process and to review documents and assumptions as part of the peer-review process. Software Platforms and Capabilities Issue: A number of travel model software platforms are available in the marketplace. Each software platform provides varying degrees of modeling capability and utility. Selection of a particular software platform and its suitability for use in regional and/or local models also vary, depending upon the expertise of model development consultant. Though there are no requirements in the selection of particular software for use by local agencies, different software platforms do add complexity in achieving model consistency between regional and local models. For example, data files transfer, re-formatting, and costs associated with resolving the data-base differences could become an issue. In addition, as traffic micro-simulation emerges from testing to application, the associated 7

8 data needs and complexity in modeling will intensify. As this occurs, uniform software and standardized protocols will become more important. Recommendations: Generally, consistency in using the same or common-base software platforms would generally minimize staff time and model development costs. Efforts should always be pursued to minimize using a wide variety of software platforms, particularly for model with the same county. For example, application of universal file transfer protocols such as GIS shape file format for graphics, excel spreadsheet or dbase formats for datasets would enhance efficiency in file sharing and minimize complications in file transfers. Software that provides uniformity and consistency would be preferred. SBCAG is particularly appreciative of the fact that the City of Lompoc, the City of Santa Barbara, and Caltrans D5 have elected to use TransCAD as their model platform, which fundamentally provided a common platform and efficiency to modeling capabilities and application. RECOMMENDATION TO FACILITATE COORDINATION BETWEEN LOCAL AND REGIONAL TRAVEL MODELS As part of the federal and state legislative requirements for model consistency, the review process allows each agency to review the other agencies travel model. It gives the regional agency the opportunity to review the validity of local models and their performance, particularly on regionally significant roadways. Conversely, local agencies would be able to streamline their modeling efforts to address their general plan land use issues while at the same time minimize development and maintenance costs. The current local model development opportunities of the Lompoc and Santa Barbara city models are a major step for locals to attain enhanced modeling capabilities to meet their needs. The peer review process would also provide a great opportunity to ensure long term model consistency between the SBCAG model and local models. It would also help the long term development and improvement of the SBCAG travel model. Staff is encouraged that local agencies remain open about how their models are being developed so that inconsistencies between the regional and local models can be minimized and decisions about transportation funding can be confidently made. It is important to recognize the common factors associated with model consistency between regional and local models. As local agencies are obligated to involve SBCAG for consistency review, staff believes that the time is now for a formal peer review process, involving SBCAG, local agencies, Caltrans, and the Consulting community, be created, perhaps a Countywide/SBCAG Model Users Group (SBCMUG) to further promote cooperation, facilitate collaboration, and streamline the model consistency efforts. As local models are likely to be more sensitive in addressing general plan policy related issues (capturing benefits of newly instituted mixed-use or smart growth strategies), successful local land use policy-driven strategies could in turn provide improvements on SBCAG model as well. This Users Group would likely just need to meet two or three times a year to review model updates, share new applications and technical developments. Attachments: Appendix F, CMP, Biennial Update, November 2003 \\Grp-SBCAG\mtgs\TTAC\2008 Mtgs\June\Draft TTAC Rpt on Model Consistency.doc 8

9 Table 1 - Travel Demand Models in Santa Barbara County Model Characteristics Travel Model Software Platform Model Type SBCAG SBCAG Travel Demand Model (Expanded Version) TransCAD 5.0 Traffix for CMP Intersection LOS analysis Socioeconomic Data-based Caltrans D5 SBCAG Travel Demand Model (Expanded Version) TransCAD 5.0 Other Traffic Operations software Same as SBCAG City of Santa Barbara Part of the Plan Santa Barbara City of Lompoc Lompoc Traffic Model (Part of City s GP Update) Santa Maria And Orcutt Area Santa Maria/Orcutt Traffic Model, 2004 City of Goleta Goleta Traffic Model, 2004 TransCAD 5.0 TransCAD 5.0 PTV/VISUM PTV/VISUM Traffix for intersection LOS analysis Land Use Data-based, but designed to be socioeconomic databased convertible Land Use Data-based Land Use Data-based Land Use Data-based Santa Ynez Valley SY Valley Traffic Model, 1992 TModel2/VISUM Land Use Data-based Capabilities Mode Choice Base & Forecast years Current Status Future Plans Daily and 3-time periods (AM, Midday, and PM) peak hour Logit model provides motorized and nonmotorized modes. Bike / Pedestrian forecasts are available, but not currently used due to the lack count data for calibration & validation 2000 Base Year 2030 Forecasts Ongoing use for countywide and corridor studies, including Caltrans CMIS, CSMP, and 101 HOV studies) Update to 2005 Base Year Continue to be used for CMIA, CSMP and other corridor studies. Same as SBCAG Same as SBCAG Same as SBCAG Same as SBCAG Daily and AM/PM peak hour Build on the SBCAG model, the city model may have mode choice capability similar to the SBCAG model Base Year Forecast year not determined. Initiated development in April 2008 as part of the PlanSB Daily and AM/PM peak hour Build on the SBCAG model with the same consultant as the SB city model, the Lompoc model may have mode choice capability similar to the SBCAG model Base Year Forecast year not determined. Initiated development as part of the City s GP Update Daily and AM/PM peak hour Transit modeling capability is available from VISUM but the mode choice step is not being used. Currently calibrated to 2008 Base Year Forecast year not determined Same as SBCAG In development In development In the process if calibrated to 2008 base year AM / PM peak hour Similar to the SM/Orcutt Model, transit modeling capability is available from VISUM but the mode choice step is not being used Base Year and 2030 GP Buildout Daily and AM/PM peak hour No Mode Choice 1992 Base Year 2015 Forecast Operational Operational Not used; Currently being converted to VISUM by PTV for coding and calibration Not yet determined Not available

10 Table 2: Model Consistency Check List (Input and Output Exchanges between Regional and Local Models) Jurisdiction Geography and network External Traffic Model Database SBCAG Regional Model (Input to Local Models) - Regional Census TAZs and updates - Census Data - Countywide and subarea network - External traffic and OD trip tables for local model input - Regional and intercity commute data and forecast of intercity transit ridership data - Socioeconomic data by market area / local jurisdiction provides control totals by jurisdiction o Population, Housing, Employment o Household Size and Income o Census and CTPP Journey-to-Work Data Local Models (Feedback to SBCAG Regional Model) - Disaggregation of regional TAZs into finer TAZs within local jurisdictional boundaries - Direct application of Census data down to localized block level - Gridded TAZs within CBD and sub-areas geography and localized networks consistent with regional TAZs to allow regional model validation - Micro level OD matrices allow subarea traffic circulation be visualized - Transit ridership supplement local model inadequacy. - Land use data from general plans review local land use policies - Equivalence conversion table validating with regional control totals and economic trends, i.e., employment and housing Traffic Counts - Cordon and screenline count volumes at or across city boundary - Countywide ADT and peak hour counts by jurisdiction - Direct count input to local models - Local counts available for input to regional model Trip Rates - Countywide trip rates - Local trip rates allows comparison of trip rates from various jurisdictions and consistency Model Output - Base year and forecast volumes by local jurisdiction - O/D Matrices provide inter-county and inter-regional travel - Regionally significant roadway volumes for local model calibration - Regional network assignment for local model input - Transit ridership forecast by local transit operator - Bike and Pedestrian output for use by local models - Local/subarea network assignment validates regional assignment, and subarea assignments validate regional model output - Regional O/D matrices consistency with local model - Transit ridership supplement local model deficiency due to the lack of mode choice model - Effectiveness of mixed use and smart growth strategies for possible regional model improvement - Local area volumes and intersection turning movements output at local level for regional model validation 10

11 APPENDIX F EVALUATION CRITERIA FOR REVIEWING TRAFFIC MODELS Part I. Review of model assumptions, geography, and input data Interested agencies should be given an opportunity early in the model development process to review the assumptions, geography, and input data used to develop transportation models. This will avoid the need to undertake costly and time consuming changes after the structure of the model has been developed. 1. Does the model address CMP legislative objectives? 2. Are external traffic estimates provided for: Through trips (and growth) and Inter-jurisdictional trips; and, are land use assumptions relating to inter-jurisdictional trips provided? 3. Are geographic boundaries (i.e. traffic zones) consistent with other regional studies? 4. Are land use analysis assumptions consistent with other regional studies? 5. Are standard traffic measurement techniques used in the methodology? Part II. Review of model output and study results After modeling scenarios or a draft report is prepared the study can be reviewed to assess how the above issues were addressed and other questions can be asked. 6. Are road improvements identified, (if needed) to mitigate traffic impacts? Is a schedule for necessary improvements provided? 7. Is an overview of modeling activities provided which describes the network and outlines trip generation, distribution, assignment, and calibration procedures? Prior to applying a transportation model to assess the impacts of development, jurisdictions should obtain review and approval of model assumptions, data, and geography as early as feasible. Documentation of the models should be submitted which addresses each of the questions posed above. Another review of the model will be necessary following publication of an actual report on the transportation study. This review will examine the factors addressed in Part I to verify their consistency and a review of factors in Part II to assess how these issues were addressed in the study. Formal approval of transportation models for use in analyzing impacts on the CMP system must be made by the CMA (SBCAG). SBCAG should be given a minimum of 15 working days to review and evaluate the information on the model using the above guidelines. SBCAG will provide a written response to the jurisdiction outlining any changes that are necessary for approval. F-1