The framework of the Travel Demand Model (TDM) updated in 2014 is complete. Minor modifications may be done to the baseline model as staff works with the public and the Board of Supervisors to finalize the 20-Year projection out to year 2035. The TDM is not a static, unchanging, fixed planning tool. It must be maintained, updated and improved over time to remain useful and relevant. The County has begun work on several projects, including the major 5-Year update of the Capital Improvement Program (CIP), and the Traffic Impact Mitigation (TIM) Fee Program. The TDM may be updated as additional data is received during the course of these projects.
County staff has been coordinating with Caltrans and the Sacramento Area Council of Governments (SACOG) since 2012 as part of the process to update the County’s TDM. On February 3, 2014, SACOG provided a letter of concurrence based on ongoing dialog with County staff. County and Caltrans staff have worked to fine-tune the TDM to address any remaining questions. As a result of this close collaboration, the County received a letter from Caltrans on September 22, 2014 stating their concurrence with the TDM and finding that it “conforms to the state-of-practice in travel demand modeling; meets overall traffic assignment validation standards suggested by FHWA and Caltrans; and is an appropriate tool for the County’s long range planning purposes."
(See Supporting Documents for Caltrans and SACOG letters.)
A Travel Demand Model (sometimes referred to as a Traffic Demand Model) is a tool for analyzing the impacts of development on the transportation system. The County’s previous travel demand model (TDM) was based on a software platform with limited capability that is no longer supported. The new TDM was developed in the CUBE/Voyager platform, using 2010 Census data and updated socioeconomic data from several sources including information from the Sacramento Area Council of Governments (SACOG). The model has a forecast horizon year of 2035.
Upon completion of the TDM, several peer reviews were completed by Kittelson and Associates Inc., Caltrans, and SACOG. El Dorado County staff met several times with both SACOG and Caltrans during the development of the new TDM, and continue to meet with both agencies in the ongoing effort of keeping the model up-to-date.
The new TDM is an essential tool for implementing the General Plan goals and policies, updating the Zoning Ordinance, planning of new roadways for the Capital Improvement Program (CIP), and updating Traffic Impact Mitigation (TIM) Fees. The TDM will help guide the County through the next twenty-five years of land use planning. The new model will be not only be used by the County but also by private companies and public agencies such as Caltrans. The County intends to keep the model current, updating it as needed to incorporate new development.
The TDM Update included updating the traffic information with current traffic and population data through a 2010 base year. The TDM was part of the overall Land Use Policy Programmatic Update (LUPPU) process. The scope of work included updating the TDM using a new software platform, creating a new Traffic Analysis Zone map, and updating the road network. The TDM also included a new growth forecast to a 20-year horizon (though 2035) based on historical growth and distribution based on General Plan goals and policies.
Following is a chronological summary of key dates related to the development of the new TDM. For a comprehensive list of Items presented to the Board on the TDM, click on the Board of Supervisors Agenda Items tab.
December 19, 2011Draft Traffic Demand Model Needs Assessment presented to the Board. The assessment highlighted areas where the existing model could be improved. The final needs assessment was completed in January 2012.
January 24, 2012Board authorized the execution of a two-year contract with Kimley-Horn and Associates, Inc. to update the County’s existing TDM with current traffic and population data, and the revised land use forecast.
April 16 and May 1, 2012Board review and comment on the Traffic Model Update major assumptions to be used to establish Achievable Development, 2025 No-Project, and 2035 Project/No Project land use forecasts for use in updating the El Dorado County Travel Demand Model as described in Kimley-Horn & Associates, Inc.’s Technical Memorandum #10: Land Use Assumptions.
June 26 and July 24, 2012Board review and comment on the Roadway Network Map and Traffic Analysis Zone Map for use in updating the TDM.
June 27, 2012Traffic Analysis Zone Design: An Overview presentation – presented to the Engineering Subcommittee for the County’s Economic Development Advisory Committee (EDAC)/TIM Fee Working Group.
June 28, 2012Public workshop on the Travel Demand Modeling was held at 7:00 PM in the Planning Commission Hearing Room located at 2850 Fairlane Court, Building C, in Placerville. The workshop provided the public with an opportunity to learn what a Travel Demand Model is and how it is an essential tool to help determine the county’s future transportation infrastructure needs. The workshop was presented by county staff, as well as representatives from Kimley-Horn & Associates Inc., the county’s project consultant.
September 25, 2012Board provided staff with direction on roadway parameters to be analyzed with the Travel Demand Model.
March 5, 2013Board authorized Amendment I to the contract with Kimley-Horn and Associates, revising the scope of services to add Component 4 which includes Task 4.1 - Rural Area Land Use Forecast, Optional Task 4.2 - Land Use Forecast Revision and Model Analysis, Optional Task 4.3 - Meetings and Documentation, and Optional task 4.4 - Additional Presentations.
July 30, 2013Board workshop to begin the preparation of the 2014 Capital Improvement Program (CIP) and the Board’s preferred growth projection option for the CIP and TIM Fee Program updates. Growth projection used as part of the land use forecast for the TDM update.
October 22, 2013Board authorized Amendment II to the contract with Kimley-Horn & Associates, revising the scope of services to add two additional tasks under Component 2 - Environmental Impact Analysis for Targeted General Plan Amendment (TGPA) and Zoning Ordinance Update and adding one additional task under Component 4 - Rural Area Land Use and extending the term through July 31, 2014.
February 24, 2014Board directed staff to provide the Board with cost and timeline estimates for three growth forecast scenarios with the same baseline assumption as the starting point for initiating the Major 5-Year CIP and TIM Fee Program updates.
March 18, 2014Board authorized Amendment III to Agreement with Kimley-Horn and Associates, Inc., expanding the scope of work and extending the term to December 31, 2015.
April 8, 2014Board approved Scenario 3 growth forecast as the starting point for initiating the Major 5-Year CIP and TIM Fee Program updates. The growth forecast is used as part of the land use forecast for the TDM update.
Board of Supervisor Agenda Items
Please note: These agenda items may not reflect the most current information and are subject to change. For the latest information on agenda items related to this project, refer to the County online agenda calendar:
Travel Demand Model Assumptions, Methodology, and Reports
Other Related Documents
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